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Gautam T, Kim E, Ng L, Choudhary V, Lima Amorim J, Loebel Roson M, Zhao R. Photooxidation-Initiated Aqueous-Phase Formation of Organic Peroxides: Delving into Formation Mechanisms. Environ Sci Technol 2024; 58:6564-6574. [PMID: 38578220 DOI: 10.1021/acs.est.3c01162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Formation of highly oxygenated molecules (HOMs) such as organic peroxides (ROOR, ROOH, and H2O2) is known to degrade food and organic matter. Gas-phase unimolecular autoxidation and bimolecular RO2 + HO2/RO2 reactions are prominently renowned mechanisms associated with the formation of peroxides. However, the reaction pathways and conditions favoring the generation of peroxides in the aqueous phase need to be evaluated. Here, we identified bulk aqueous-phase ROOHs in varying organic precursors, including a laboratory model compound and monoterpene oxidation products. Our results show that formation of ROOHs is suppressed at enhanced oxidant concentrations but exhibits complex trends at elevated precursor concentrations. Furthermore, we observed an exponential increase in the yield of ROOHs when UV light with longer wavelengths was used in the experiment, comparing UVA, UVB, and UVC. Water-soluble organic compounds represent a significant fraction of ambient cloud-water components (up to 500 μM). Thus, the reaction pathways facilitating the formation of HOMs (i.e., ROOHs) during the aqueous-phase oxidation of water-soluble species add to the climate and health burden of atmospheric particulate matter.
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Affiliation(s)
- Tania Gautam
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Erica Kim
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Lisa Ng
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Vikram Choudhary
- Air Pollution Exposure Laboratory, Division of Respiratory Medicine, Department of Medicine, Vancouver Coastal Health Research Institute, The University of British Columbia, Vancouver, British Columbia V5Z1W9, Canada
| | - Jessica Lima Amorim
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Max Loebel Roson
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Ran Zhao
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
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2
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Zhang Y, Zhao B, Liu L, Zhou J, Ma X, Wang N. Efficient Tin Perovskite Solar Cells via Suppressing Autoxidation in Inert Atmosphere. Small 2024; 20:e2306115. [PMID: 37775951 DOI: 10.1002/smll.202306115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/22/2023] [Indexed: 10/01/2023]
Abstract
The unsatisfactory power conversion efficiency (PCE) and long-term stability of tin perovskite solar cells (TPSCs) restrict its further development as alternatives to lead perovskite solar cells (LPSCs). Considerable research has focused on the negative impacts of O2 and H2 O, while discussions about degradation mechanism in an inert atmosphere remains insufficient. Herein, the light-induced autoxidation of tin perovskite in nitrogen atmosphere is revealed for the first time and the elastic lattice distortion is demonstrated as the crucial role of rapid degradation. The continuous injection of photons induces energy transfer from excited A-site cations to vibrating Sn-I framework, leading to the elastic deformation of perovskite lattice. Consequently, the over distorted Sn-I framework releases free iodine and further oxidizes Sn2+ in the form of molecular iodine. Through an appropriately designed light-dark cyclic test, a remarkable PCE of 14.41% is achieved based on (Cs0.025 (MA0.25 FA0.75 )0.975 ) 0.98 EDA0.01 SnI3 solar cells, which is the record of hybrid triple TPSCs so far. The findings unveil autoxidation as the crux of TPSCs' degradation in an inert atmosphere and suggest the possibility of reinforcing the tin perovskite lattice towards highly efficient and stable TPSCs.
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Affiliation(s)
- Yu Zhang
- College of Physics, Jilin University, Changchun, 130012, P. R. China
| | - Bin Zhao
- College of Physics, Jilin University, Changchun, 130012, P. R. China
| | - Lang Liu
- College of Physics, Jilin University, Changchun, 130012, P. R. China
| | - Jianheng Zhou
- College of Physics, Jilin University, Changchun, 130012, P. R. China
| | - Xue Ma
- College of Physics, Jilin University, Changchun, 130012, P. R. China
| | - Ning Wang
- College of Physics, Jilin University, Changchun, 130012, P. R. China
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3
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Schaich KM. Epoxides: an underestimated lipid oxidation product. Free Radic Res 2023:1-48. [PMID: 38124354 DOI: 10.1080/10715762.2023.2277142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 08/09/2023] [Indexed: 12/23/2023]
Abstract
Immense gains in understanding of mechanisms and effects of lipid oxidation have been achieved in the nearly 90 years over which lipid oxidation has been an active research focus. Even so, the substantial questions still being raised about lipid oxidation in this special issue show clearly that missing pieces remain and must be considered for full accounting of this important reaction in any system. In this context, epoxides are spotlighted as a critical overlooked product of lipid autoxidation - underestimated in analysis, underestimated in presence as a functionally active and competitive intermediate and product of lipid oxidation, and underestimated in potential contributions to impact of lipid oxidation on other molecules and cell functions. Logical reasons for ignoring or not finding epoxides are offered in historical development of lipid oxidation knowledge. Reactions generating lipid epoxides in autoxidation are reviewed, limitations in detecting and tracking epoxides are outlined to explain why epoxides may not be detected when they should be present, and justifications for increased research and analysis of epoxides are argued. The main goal is to provide a context for recognizing epoxides as critical products that must be accounted for in determining the state rather than extent of lipid oxidation and in tracking its consequences in oils, foods, personal care products, and tissues. A secondary goal is to stimulate new research using contemporary analyses to fill in the gaps of knowledge about epoxide formation, structure, and reactions in lipid autoxidation.
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Affiliation(s)
- Karen M Schaich
- Department of Food Science, Rutgers University, New Brunswick, NJ, USA
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4
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Horký F, Franz R, Bruhn C, Pietschnig R. A General Strategy for Increasing the Air Stability of Phosphines Including Primary Phosphines. Chemistry 2023; 29:e202302518. [PMID: 37650772 DOI: 10.1002/chem.202302518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/31/2023] [Accepted: 08/31/2023] [Indexed: 09/01/2023]
Abstract
A general approach for increasing the air-stability of various primary phosphines in the absence of kinetic stabilization is presented that contrasts with previous interpretations, which were limited to specific phosphines. This contribution shows the synthesis of a series of air-stable primary phosphines Fc(CH2 )n PH2 , where n=0,1,2,3; and Fc=ferrocenyl, and their corresponding isolable primary phosphine oxides. It was demonstrated that the ferrocene moiety exerts an antioxidant effect on the primary phosphine group, which is intermolecular, solvent dependent and increases with the electron density on the ferrocene moiety. Furthermore, we demonstrated that the presence of ferrocene in solution also inhibits the oxidation of other secondary and tertiary phosphines in air. Together our findings suggest that quenching of singlet oxygen is the actual reason for the antioxidant effect; this was experimentally confirmed by using other established singlet oxygen quenchers, thus demonstrating a key role of singlet oxygen in the aerobic oxidation of phosphines.
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Affiliation(s)
- Filip Horký
- Institute for Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
| | - Roman Franz
- Institute for Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
| | - Clemens Bruhn
- Institute for Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
| | - Rudolf Pietschnig
- Institute for Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
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5
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Zhou Z, Crilley LR, Ditto JC, VandenBoer TC, Abbatt JPD. Chemical Fate of Oils on Indoor Surfaces: Ozonolysis and Peroxidation. Environ Sci Technol 2023; 57:15546-15557. [PMID: 37647222 DOI: 10.1021/acs.est.3c04009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Unsaturated triglycerides found in food and skin oils are reactive in ambient air. However, the chemical fate of such compounds has not been well characterized in genuine indoor environments. Here, we monitored the aging of oil coatings on glass surfaces over a range of environmental conditions, using mass spectrometry, nuclear magnetic resonance (NMR), and electron paramagnetic resonance (EPR) techniques. Upon room air exposure (up to 17 ppb ozone), the characteristic ozonolysis products, secondary ozonides, were observed on surfaces near the cooking area of a commercial kitchen, along with condensed-phase aldehydes. In an office setting, ozonolysis is also the dominant degradation pathway for oil films exposed to air. However, for indoor enclosed spaces such as drawers, the depleted air flow makes lipid autoxidation more favorable after an induction period of a few days. Forming hydroperoxides as the major primary products, this radical-mediated peroxidation behavior is accelerated by indoor direct sunlight, but the initiation step in dark settings is still unclear. These results are in accord with radical measurements, indicating that indoor photooxidation facilitates radical formation on surfaces. Overall, many intermediate and end products observed are reactive oxygen species (ROS) that may induce oxidative stress in human bodies. Given that these species can be widely found on both food and household surfaces, their toxicological properties are worth further attention.
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Affiliation(s)
- Zilin Zhou
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Leigh R Crilley
- Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada
| | - Jenna C Ditto
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | | | - Jonathan P D Abbatt
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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Sadžak A, Eraković M, Šegota S. Kinetics of Flavonoid Degradation and Controlled Release from Functionalized Magnetic Nanoparticles. Mol Pharm 2023; 20:5148-5159. [PMID: 37651612 DOI: 10.1021/acs.molpharmaceut.3c00478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
Flavonoids are naturally occurring antioxidants that have been shown to protect cell membranes from oxidative stress and have a potential use in photodynamic cancer treatment. However, they degrade at physiological pH values, which is often neglected in drug release studies. Kinetic study of flavonoid oxidation can help to understand the mechanism of degradation and to correctly analyze flavonoid release data. Additionally, the incorporation of flavonoids into magnetic nanocarriers can be utilized to mitigate degradation and overcome their low solubility, while the release can be controlled using magnetic fields (MFs). An approach that combines alternating least squares (ALS) and multilinear regression to consider flavonoid autoxidation in release studies is presented. This approach can be used in general cases to account for the degradation of unstable drugs released from nanoparticles. The oxidation of quercetin, myricetin (MCE), and myricitrin (MCI) was studied in PBS buffer (pH = 7.4) using UV-vis spectrophotometry. ALS was used to determine the kinetic profiles and characteristic spectra, which were used to analyze UV-vis data of release from functionalized magnetic nanoparticles (MNPs). MNPs were selected for their unique magnetic properties, which can be exploited for both targeted drug delivery and control over the drug release. MNPs were prepared and characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, superconducting quantum interference device magnetometer, and electrophoretic mobility measurements. Autoxidation of all three flavonoids follows a two-step first-order kinetic model. MCE showed the fastest degradation, while the oxidation of MCI was the slowest. The flavonoids were successfully loaded into the prepared MNPs, and the drug release was described by the first-order and Korsmeyer-Peppas models. External MFs were utilized to control the release mechanism and the cumulative mass of the flavonoids released.
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Affiliation(s)
- Anja Sadžak
- Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička Cesta 54, Zagreb 10000, Croatia
| | - Mihael Eraković
- Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička Cesta 54, Zagreb 10000, Croatia
| | - Suzana Šegota
- Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička Cesta 54, Zagreb 10000, Croatia
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Kozuch B, Weber J, Buske J, Mäder K, Garidel P, Diederichs T. Comparative Stability Study of Polysorbate 20 and Polysorbate 80 Related to Oxidative Degradation. Pharmaceutics 2023; 15:2332. [PMID: 37765302 PMCID: PMC10537708 DOI: 10.3390/pharmaceutics15092332] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/01/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
The surfactants polysorbate 20 (PS20) and polysorbate 80 (PS80) are utilized to stabilize protein drugs. However, concerns have been raised regarding the degradation of PSs in biologics and the potential impact on product quality. Oxidation has been identified as a prevalent degradation mechanism under pharmaceutically relevant conditions. So far, a systematic stability comparison of both PSs under pharmaceutically relevant conditions has not been conducted and little is known about the dependence of oxidation on PS concentration. Here, we conducted a comparative stability study to investigate (i) the different oxidative degradation propensities between PS20 and PS80 and (ii) the impact of PS concentration on oxidative degradation. PS20 and PS80 in concentrations ranging from 0.1 mg⋅mL-1 to raw material were stored at 5, 25, and 40 °C for 48 weeks in acetate buffer pH 5.5 and water, respectively. We observed a temperature-dependent oxidative degradation of the PSs with strong (40 °C), moderate (25 °C), and weak/no degradation (5 °C). Especially at elevated temperatures such as 40 °C, fast oxidative PS degradation processes were detected. In this case study, a stronger degradation and earlier onset of oxidation was observed for PS80 in comparison to PS20, detected via the fluorescence micelle assay. Additionally, degradation was found to be strongly dependent on PS concentration, with significantly less oxidative processes at higher PS concentrations. Iron impurities, oxygen in the vial headspaces, and the pH values of the formulations were identified as the main contributing factors to accelerate PS oxidation.
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Affiliation(s)
- Benedykt Kozuch
- PDB-TIP, Innovation Unit, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Straße 65, 88397 Biberach an der Riss, Germany
| | - Johanna Weber
- Institute of Pharmacy, Faculty of Biosciences, Martin-Luther-University Halle-Wittenberg, Wolfgang-Langenbeck-Strasse 4, 06120 Halle, Germany
| | - Julia Buske
- PDB-TIP, Innovation Unit, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Straße 65, 88397 Biberach an der Riss, Germany
| | - Karsten Mäder
- Institute of Pharmacy, Faculty of Biosciences, Martin-Luther-University Halle-Wittenberg, Wolfgang-Langenbeck-Strasse 4, 06120 Halle, Germany
| | - Patrick Garidel
- PDB-TIP, Innovation Unit, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Straße 65, 88397 Biberach an der Riss, Germany
| | - Tim Diederichs
- PDB-TIP, Innovation Unit, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Straße 65, 88397 Biberach an der Riss, Germany
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Abstract
Lipid peroxidation (LP) is the most important type of oxidative-radical damage in biological systems, owing to its interplay with ferroptosis and to its role in secondary damage to other biomolecules, such as proteins. The chemistry of LP and its biological consequences are reviewed with focus on the kinetics of the various processes, which helps understand the mechanisms and efficacy of antioxidant strategies. The main types of antioxidants are discussed in terms of structure-activity rationalization, with focus on mechanism and kinetics, as well as on their potential role in modulating ferroptosis. Phenols, pyri(mi)dinols, antioxidants based on heavy chalcogens (Se and Te), diarylamines, ascorbate and others are addressed, along with the latest unconventional antioxidant strategies based on the double-sided role of the superoxide/hydroperoxyl radical system.
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Affiliation(s)
- Luca Valgimigli
- Department of Chemistry "G. Ciamician", University of Bologna, Via Piero Gobetti 85, 40129 Bologna, Italy
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Volkov V, Lobanov A, Voronkov M, Baygildiev T, Misin V, Tsivileva O. Kinetics and Mechanism of Epinephrine Autoxidation in the Presence of Plant Superoxide Inhibitors: A New Look at the Methodology of Using a Model System in Biological and Chemical Research. Antioxidants (Basel) 2023; 12:1530. [PMID: 37627525 PMCID: PMC10451219 DOI: 10.3390/antiox12081530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/18/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
Superoxide is the primary active oxygen form produced in living organisms. Because of superoxide anion radical formation during epinephrine oxidation in alkaline medium, this system is offered in some works for antioxidant activity analysis, however, without enough physicochemical justification. Therefore, the task of developing reliable methods for analyzing the superoxide inhibition activity of various objects is very urgent. In this work, a kinetic model of epinephrine autoxidation in an alkaline medium in the presence of antioxidants of plant origin is proposed. The participation of chain reactions with long oxidation chains in this process is revealed. The limiting stage of the process is a one-electron reduction of oxygen by the anionic forms of the phenolic hydroxyls of epinephrine. The appearance of the absorption maximum at a wavelength of 347 nm during epinephrine autoxidation is associated with adrenolutin formation, which is confirmed by HPLC/UV/MS. No adduct formation between phenolic antioxidants and epinephrine oxidation products was found. The complex U-shaped character of epinephrine autoxidation rate dependence on the content of antioxidants in the reaction system was shown. The study of the kinetics of epinephrine autoxidation in the presence of an individual phenolic plant superoxide inhibitor, chlorogenic acid, was carried out for the first time. The inhibitory effect of yarrow, chamomile, and bur beggar-ticks plant extracts in the adrenaline system was examined.
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Affiliation(s)
- Vladimir Volkov
- Laboratory of Chemistry of Antioxidants, N.M. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygin Street, Moscow 119334, Russia; (M.V.); (V.M.)
| | - Anton Lobanov
- Department of Dynamics of Chemical and Biological Processes, N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 4 Kosygin Street, Moscow 119991, Russia;
| | - Mikhail Voronkov
- Laboratory of Chemistry of Antioxidants, N.M. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygin Street, Moscow 119334, Russia; (M.V.); (V.M.)
| | - Timur Baygildiev
- Department of Chemistry, Lomonosov Moscow State University, 1-3 Leninskie Gory, Moscow 119991, Russia;
- Amsterdam Institute for Life and Environment (A-LIFE), Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Vyacheslav Misin
- Laboratory of Chemistry of Antioxidants, N.M. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygin Street, Moscow 119334, Russia; (M.V.); (V.M.)
| | - Olga Tsivileva
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Saratov Scientific Centre of the Russian Academy of Sciences (IBPPM RAS), 13 Prospekt Entuziastov, Saratov 410049, Russia
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Schöneich C. Primary Processes of Free Radical Formation in Pharmaceutical Formulations of Therapeutic Proteins. Biomolecules 2023; 13:1142. [PMID: 37509177 PMCID: PMC10376966 DOI: 10.3390/biom13071142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Oxidation represents a major pathway for the chemical degradation of pharmaceutical formulations. Few specific details are available on the mechanisms that trigger oxidation reactions in these formulations, specifically with respect to the formation of free radicals. Hence, these mechanisms must be formulated based on information on impurities and stress factors resulting from manufacturing, transportation and storage. In more detail, this article focusses on autoxidation, metal-catalyzed oxidation, photo-degradation and radicals generated from cavitation as a result of mechanical stress. Emphasis is placed on probable rather than theoretically possible pathways.
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Affiliation(s)
- Christian Schöneich
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, KS 66047, USA
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Setshedi IB, Lemmerer A, Smith MG. Co-crystallization of N'-benzyl-idene-pyridine-4-carbohydrazide and benzoic acid via autoxidation of benzaldehyde. Acta Crystallogr E Crystallogr Commun 2023; 79:682-685. [PMID: 37601390 PMCID: PMC10439410 DOI: 10.1107/s2056989023005698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/28/2023] [Indexed: 08/22/2023]
Abstract
The 1:1 co-crystal N'-[(2-methyl-phen-yl)methyl-idene]pyridine-4-carbohydrazide-benzoic acid (1/1), C13H11N3O·C7H6O2, formed unexpectedly after autoxidation of benzaldehyde during the slow evaporation process of a solution of isoniazid in benzaldehyde. The original intent of the synthesis was to modify isoniazid with benzaldehyde and crystallize the product in order to improve efficacy against Mycobacteria species, but benzoic acid formed spontaneously and co-crystallized with the intended product, N'-benzyl-idene-pyridine-4-carbohydrazide.
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Affiliation(s)
- Itumeleng B. Setshedi
- University of South Africa, Department of Life Science, Unisa Science Campus, 28 Pioneer Avenue, Florida, Roodepoort, Gauteng, South Africa
| | - Andreas Lemmerer
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, Gauteng, South Africa
| | - Mark G. Smith
- University of South Africa, Chemistry Department, Unisa Science Campus, 28 Pioneer Avenue, Florida, Roodepoort, Gauteng, South Africa
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Liu Q, Lei M, Zhao W, Li X, Zeng X, Bai W. Formation of Lipid-Derived Flavors in Dry-Cured Mackerel ( Scomberomorus niphonius) via Simulation of Autoxidation and Lipoxygenase-Induced Fatty Acid Oxidation. Foods 2023; 12:2504. [PMID: 37444242 DOI: 10.3390/foods12132504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 06/14/2023] [Accepted: 06/17/2023] [Indexed: 07/15/2023] Open
Abstract
In this study, lipoxygenase (LOX) extracted from dry-cured mackerel was purified, resulting in a 4.1-fold purification factor with a specific activity of 493.60 U/min·g. LOX enzymatic properties were assessed, referring to its optimal storage time (1-2 days), temperature (30 °C), and pH value (7.0). The autoxidation and LOX-induced oxidation of palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:2n9c), linoleic acid (C18:2n6c), arachidonic acid (C20:4), EPA (C20:5), and DHA (C22:6n3) were simulated to explore the main metabolic pathways of key flavors in dry-cured mackerel. The results showed that the highest LOX activity was observed when arachidonic acid was used as a substrate. Aldehydes obtained from LOX-treated C18:1n9c and C18:2n6c oxidation, which are important precursors of flavors, were the most abundant. The key flavors in dry-cured mackerel were found in the oxidative products of C16:0, C18:0, C18:1n9c, C18:2n6c, and C20:4. Heptanaldehyde could be produced from autoxidation or LOX-induced oxidation of C18:0 and C18:1n9c, while nonal could be produced from C18:1n9c and C18:2n6c oxidation. Metabolic pathway analysis revealed that C18:1n9c, C18:2n6c, EPA, and DHA made great contributions to the overall flavor of dry-cured mackerel. This study may provide a relevant theoretical basis for the scientific control of the overall taste and flavor of dry-cured mackerel and further standardize its production.
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Affiliation(s)
- Qiaoyu Liu
- College of Light Industry and Food Sciences, Academy of Contemporary Agricultural Engineering Innovations, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
- Guangdong Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
- Key Laboratory of Green Processing and Intelligent Manufacturing of Lingnan Specialty Food, Ministry of Agriculture, Guangzhou 510225, China
| | - Menglin Lei
- College of Light Industry and Food Sciences, Academy of Contemporary Agricultural Engineering Innovations, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
- Guangdong Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
- Key Laboratory of Green Processing and Intelligent Manufacturing of Lingnan Specialty Food, Ministry of Agriculture, Guangzhou 510225, China
| | - Wenhong Zhao
- College of Light Industry and Food Sciences, Academy of Contemporary Agricultural Engineering Innovations, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
- Guangdong Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
- Key Laboratory of Green Processing and Intelligent Manufacturing of Lingnan Specialty Food, Ministry of Agriculture, Guangzhou 510225, China
| | - Xiangluan Li
- College of Light Industry and Food Sciences, Academy of Contemporary Agricultural Engineering Innovations, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
- Guangdong Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
- Key Laboratory of Green Processing and Intelligent Manufacturing of Lingnan Specialty Food, Ministry of Agriculture, Guangzhou 510225, China
| | - Xiaofang Zeng
- College of Light Industry and Food Sciences, Academy of Contemporary Agricultural Engineering Innovations, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
- Guangdong Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
- Key Laboratory of Green Processing and Intelligent Manufacturing of Lingnan Specialty Food, Ministry of Agriculture, Guangzhou 510225, China
| | - Weidong Bai
- College of Light Industry and Food Sciences, Academy of Contemporary Agricultural Engineering Innovations, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
- Guangdong Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
- Key Laboratory of Green Processing and Intelligent Manufacturing of Lingnan Specialty Food, Ministry of Agriculture, Guangzhou 510225, China
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Tsikas D. GC-MS Studies on Nitric Oxide Autoxidation and S-Nitrosothiol Hydrolysis to Nitrite in pH-Neutral Aqueous Buffers: Definite Results Using 15N and 18O Isotopes. Molecules 2023; 28:molecules28114281. [PMID: 37298756 DOI: 10.3390/molecules28114281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/19/2023] [Accepted: 05/20/2023] [Indexed: 06/12/2023] Open
Abstract
Nitrite (O=N-O-, NO2-) and nitrate (O=N(O)-O-, NO3-) are ubiquitous in nature. In aerated aqueous solutions, nitrite is considered the major autoxidation product of nitric oxide (●NO). ●NO is an environmental gas but is also endogenously produced from the amino acid L-arginine by the catalytic action of ●NO synthases. It is considered that the autoxidation of ●NO in aqueous solutions and in O2-containing gas phase proceeds via different neutral (e.g., O=N-O-N=O) and radical (e.g., ONOO●) intermediates. In aqueous buffers, endogenous S-nitrosothiols (thionitrites, RSNO) from thiols (RSH) such as L-cysteine (i.e., S-nitroso-L-cysteine, CysSNO) and cysteine-containing peptides such as glutathione (GSH) (i.e., S-nitrosoglutathione, GSNO) may be formed during the autoxidation of ●NO in the presence of thiols and dioxygen (e.g., GSH + O=N-O-N=O → GSNO + O=N-O- + H+; pKaHONO, 3.24). The reaction products of thionitrites in aerated aqueous solutions may be different from those of ●NO. This work describes in vitro GC-MS studies on the reactions of unlabeled (14NO2-) and labeled nitrite (15NO2-) and RSNO (RS15NO, RS15N18O) performed in pH-neutral aqueous buffers of phosphate or tris(hydroxyethylamine) prepared in unlabeled (H216O) or labeled H2O (H218O). Unlabeled and stable-isotope-labeled nitrite and nitrate species were measured by gas chromatography-mass spectrometry (GC-MS) after derivatization with pentafluorobenzyl bromide and negative-ion chemical ionization. The study provides strong indication for the formation of O=N-O-N=O as an intermediate of ●NO autoxidation in pH-neutral aqueous buffers. In high molar excess, HgCl2 accelerates and increases RSNO hydrolysis to nitrite, thereby incorporating 18O from H218O into the SNO group. In aqueous buffers prepared in H218O, synthetic peroxynitrite (ONOO-) decomposes to nitrite without 18O incorporation, indicating water-independent decomposition of peroxynitrite to nitrite. Use of RS15NO and H218O in combination with GC-MS allows generation of definite results and elucidation of reaction mechanisms of oxidation of ●NO and hydrolysis of RSNO.
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Affiliation(s)
- Dimitrios Tsikas
- Core Unit Proteomics, Institute of Toxicology, Hannover Medical School, 30625 Hannover, Germany
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14
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Schubert S, Geier J, Brans R, Heratizadeh A, Kränke B, Schnuch A, Bauer A, Dickel H, Buhl T, Vieluf D, Wagner N, Worm M. Patch testing hydroperoxides of limonene and linalool in consecutive patients-Results of the IVDK 2018-2020. Contact Dermatitis 2023. [PMID: 37177844 DOI: 10.1111/cod.14332] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 04/21/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023]
Abstract
BACKGROUND Hydroperoxides of limonene (Lim-OOHs) and linalool (Lin-OOHs) are potent contact sensitizers. OBJECTIVES To investigate the prevalence of positive patch test (PT) reactions to Lim-OOHs and Lin-OOHs in consecutive patients, their demographic factors and concomitant reactions. METHODS Between 7/2018 and 12/2020, Lim-OOHs 0.3% pet. and Lin-OOHs 1% pet. were patch tested in 5511 consecutive patients. We assessed PT reactivity and analysed data from patients with either positive or negative PTs to Lim-OOHs and Lin-OOHs. RESULTS Positive PT results to Lim-OOHs (n = 170, 3.1%) and Lin-OOHs (n = 483, 8.8%) were frequent. Most of the positive reactions were weak (LimOOHs n = 134/LinOOHs n = 429), and even more frequently, doubtful (n = 252/n = 578) or irritant reactions (n = 81/n = 178) were documented. PT reactivity to Lim-OOHs and Lin-OOHs was increased in patients with irritant reactions to sodium lauryl sulphate (SLS). The proportion of leg dermatitis and concomitant positive reactions to fragrances and essential oils was increased in patients with reactivity to these hydroperoxides. CONCLUSION The observed reaction pattern suggests that both test preparations display an irritant potential with an increased risk of false positive reactions. Preparations should be chemically monitored in order to reduce irritancy. Mindful interpretation of PT results and aimed patch testing of lower concentrations is recommended.
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Affiliation(s)
- Steffen Schubert
- Information Network of Departments of Dermatology (IVDK), Institute at the University Medical Centre Göttingen, Göttingen, Germany
| | - Johannes Geier
- Information Network of Departments of Dermatology (IVDK), Institute at the University Medical Centre Göttingen, Göttingen, Germany
| | - Richard Brans
- Institute for Interdisciplinary Dermatologic Prevention and Rehabilitation (iDerm) at the University of Osnabrück, Osnabrück, Germany
- Department of Dermatology, Environmental Medicine, and Health Theory, University of Osnabrück, Osnabrück, Germany
| | - Annice Heratizadeh
- Department of Dermatology and Allergy, Division of Immunodermatology and Allergy Research, Hannover Medical School, Hannover, Germany
| | - Birger Kränke
- Department of Dermatology and Venerology, Medical University of Graz, Graz, Austria
| | - Axel Schnuch
- Information Network of Departments of Dermatology (IVDK), Institute at the University Medical Centre Göttingen, Göttingen, Germany
| | - Andrea Bauer
- Department of Dermatology, University Allergy Center, University Hospital Carl Gustav Carus, Technical University Dresden, Dresden, Germany
| | - Heinrich Dickel
- Department of Dermatology, Venereology and Allergology, St. Josef Hospital, University Medical Center, Ruhr University Bochum, Bochum, Germany
| | - Timo Buhl
- Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, Göttingen, Germany
| | - Dieter Vieluf
- Department of Allergology, Photodermatology and Occupational Dermatology, Dermatologikum Hamburg, Hamburg, Germany
| | - Nicola Wagner
- Department of Dermatology, Erlangen University Hospital, Friedrich-Alexander-University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Margitta Worm
- Division of Allergy and Immunology, Department of Dermatology, Venereology and Allergy, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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15
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Koch E, Löwen A, Nikolay S, Willenberg I, Schebb NH. Trans-Hydroxy, Trans-Epoxy, and Erythro-dihydroxy Fatty Acids Increase during Deep-Frying. J Agric Food Chem 2023; 71:7508-7513. [PMID: 37141304 DOI: 10.1021/acs.jafc.3c00964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Deep-frying of food is a common cooking technique causing thermal oxidation of fatty acids (FA). Here, we investigated for the first time the formation of hydroxy-, epoxy- and dihydroxy-FA derived from oleic, linoleic (LA), and α-linolenic acid (ALA) during frying. Potato chips were fried in high-oleic sunflower oil for 4 × 5 cycles on 2 days, and the oil was comprehensively analyzed by liquid chromatography-tandem mass spectrometry. During frying, the E,Z-9- and E,Z-13-hydroperoxy-LA and -ALA concentrations decrease while their corresponding hydroxy-FA remain constant. The concentrations of both E,E-9-/13-hydroperoxy-LA and E,E-9-/13-hydroxy-LA increase with the frying cycles, which is also found for the concentration of trans-epoxy-FA. The increase in trans-epoxy-FA is more pronounced than that of the corresponding cis-epoxy-FA, exceeding their concentrations on the second day of frying. This selective change in the cis-/trans-epoxy-FA ratio is also observed for their hydrolysis products: concentrations of erythro-dihydroxy-FA, derived from trans-epoxy-FA, increase during frying stronger than threo-dihydroxy-FA derived from cis-epoxy-FA. Based on these data, we suggest that the ratio of E,E-/E,Z-hydroxy-FA, in combination with the cis-/trans-epoxy-FA ratio, as well as the threo-/erythro-dihydroxy-FA ratio are promising new parameters to evaluate the heating of edible oils and to characterize the status of frying oils.
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Affiliation(s)
- Elisabeth Koch
- Chair of Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Gaussstrasse 20, 42119 Wuppertal, Germany
| | - Ariane Löwen
- Chair of Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Gaussstrasse 20, 42119 Wuppertal, Germany
| | - Sharline Nikolay
- Department of Safety and Quality of Cereals, Max Rubner-Institut (MRI)─Federal Research Institute of Nutrition and Food, Schützenberg 12, 32756 Detmold, Germany
| | - Ina Willenberg
- Department of Safety and Quality of Cereals, Max Rubner-Institut (MRI)─Federal Research Institute of Nutrition and Food, Schützenberg 12, 32756 Detmold, Germany
| | - Nils Helge Schebb
- Chair of Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Gaussstrasse 20, 42119 Wuppertal, Germany
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16
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Hu Z, Di Q, Liu B, Li Y, He Y, Zhu Q, Xu Q, Dagaut P, Hansen N, Sarathy SM, Xing L, Truhlar DG, Wang Z. Elucidating the photodissociation fingerprint and quantifying the determination of organic hydroperoxides in gas-phase autoxidation. Proc Natl Acad Sci U S A 2023; 120:e2220131120. [PMID: 36848575 PMCID: PMC10013783 DOI: 10.1073/pnas.2220131120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 01/12/2023] [Indexed: 03/01/2023] Open
Abstract
Hydroperoxides are formed in the atmospheric oxidation of volatile organic compounds, in the combustion autoxidation of fuel, in the cold environment of the interstellar medium, and also in some catalytic reactions. They play crucial roles in the formation and aging of secondary organic aerosols and in fuel autoignition. However, the concentration of organic hydroperoxides is seldom measured, and typical estimates have large uncertainties. In this work, we developed a mild and environmental-friendly method for the synthesis of alkyl hydroperoxides (ROOH) with various structures, and we systematically measured the absolute photoionization cross-sections (PICSs) of the ROOHs using synchrotron vacuum ultraviolet-photoionization mass spectrometry (SVUV-PIMS). A chemical titration method was combined with an SVUV-PIMS measurement to obtain the PICS of 4-hydroperoxy-2-pentanone, a typical molecule for combustion and atmospheric autoxidation ketohydroperoxides (KHPs). We found that organic hydroperoxide cations are largely dissociated by loss of OOH. This fingerprint was used for the identification and accurate quantification of the organic peroxides, and it can therefore be used to improve models for autoxidation chemistry. The synthesis method and photoionization dataset for organic hydroperoxides are useful for studying the chemistry of hydroperoxides and the reaction kinetics of the hydroperoxy radicals and for developing and evaluating kinetic models for the atmospheric autoxidation and combustion autoxidation of the organic compounds.
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Affiliation(s)
- Zhihong Hu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui230029, P. R. China
| | - Qimei Di
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui230029, P. R. China
| | - Bingzhi Liu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui230029, P. R. China
| | - Yanbo Li
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui230029, P. R. China
| | - Yunrui He
- Energy and Power Engineering Institute, Henan University of Science and Technology, Luoyang, Henan471003, China
| | - Qingbo Zhu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui230029, P. R. China
| | - Qiang Xu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui230029, P. R. China
| | - Philippe Dagaut
- CNRS, Institut National des Sciences de l’Ingénierie et des Systèmes, Institut de Combustion, Aérothermique, Réactivité et Environnement, Orléans45071, cedex 2, France
| | - Nils Hansen
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA94551
| | - S. Mani Sarathy
- King Abdullah University of Science and Technology, Clean Combustion Research Center, Thuwal23955-6900, Saudi Arabia
| | - Lili Xing
- Energy and Power Engineering Institute, Henan University of Science and Technology, Luoyang, Henan471003, China
| | - Donald G. Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN55455-0431
| | - Zhandong Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui230029, P. R. China
- State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui230026, P. R. China
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17
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Iyer J, Brunsteiner M, Ray A, Davis A, Saraf I, Paudel A. Theoretical and Experimental Investigation of Autoxidation Propensity of Selected Drugs in Solution State. Mol Pharm 2023; 20:1768-1778. [PMID: 36757102 DOI: 10.1021/acs.molpharmaceut.2c00967] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The C-H bond dissociation energy (BDE) of drug molecules is often used to estimate their relative propensities to undergo autoxidation. BDE calculations based on electronic structures provide a convenient means to estimate the risk for a given compound to degrade via autoxidation. This study aimed to verify the utility of calculated C-H BDEs of a range of drug molecules in predicting their autoxidation propensities, in the solution state. For the autoxidation study, 2,2'-azobis (2-methylpropionitrile) was employed as the solution state stressor, and the experimental reaction rate constants were determined employing ultraperformance liquid chromatographic (UPLC) methods. Reaction rates in the solution state were compared to the calculated C-H BDE values of the respective compounds. The results indicated a poor correlation for compounds in the solution state, and their relative stabilities could not be explained with C-H BDE. On the other hand, a favorable relationship was observed between the relative extent of ionization and the autoxidation rates of the selected compounds. In the solution state, factors such as the type and extent of drug ionization, degree and type of solvation have been shown to contribute to differences in reactivity. By applying the computational method involving the effect of H-atom abstraction and potential ionization sites in the molecule, the calculated C-H BDE should relate better to the experimental autoxidation rates.
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Affiliation(s)
- Jayant Iyer
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz 8010, Austria
| | | | - Andrew Ray
- Dew Modalities Product Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Adrian Davis
- Pfizer Worldwide Research and Development, Sandwich, Kent CT13 9NJ, United Kingdom
| | - Isha Saraf
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz 8010, Austria
| | - Amrit Paudel
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz 8010, Austria.,Graz University of Technology, Institute of Process and Particle Engineering, Graz 8010, Austria
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18
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Abstract
Mechanoactivation has attracted considerable attention in the pharmaceutical sciences due to its ability to generate amorphous materials and solid-state synthetic products without the use of solvent. Although some studies have reported drug degradation during milling, no studies have systematically investigated the use of mechanoactivation in predicting drug degradation in the solid state. Thus, this work explores the autoxidation of drugs in the solid state by comilling amorphous mifepristone (MFP):polyvinylpyrrolidone vinyl acetate (PVPVA) and amorphous olanzapine (OLA):PVPVA. MFP was amorphized by ball milling and OLA by quench cooling techniques. Subsequently, comilling the amorphous drugs in the presence of a 10-fold weight ratio of PVPVA (the excipient containing reactive free radicals) was performed at several milling frequencies to identify the kinetics of mechano-autoxidation over milling durations. Overall, milling led to the degradation of up to 5% drug in the solid state. The autoxidation mechanism was confirmed by performing a stress study in the solution at 50 °C for 5 h, by using a 10 mM azo-bis(isobutyronitrile) (AIBN) as a stressing agent. By deconvoluting the effect of milling frequency and the energy on the extent and kinetics of milling-induced autoxidation of amorphous drugs, it was possible to fit an extended Arrhenius model that allowed extrapolation of mechanoactivated degradation rates (Km) to zero milling frequencies. Further, the autoxidation rates of drugs stored at high temperatures were observed to follow an Arrhenius behavior. A good degree of agreement was observed between the model predictions obtained by mechanoactivation (Km) to the reaction rates observed under accelerated temperatures. Additionally, the impact of adding an antioxidant (e.g., butylated hydroxytoluene) to the mixture during comilling was also examined. This study can be helpful in evaluating the stability of amorphous solids stored in accelerated (non-hermetic) conditions, in screening solid-state autoxidation propensity of drugs, and for the rational selection of antioxidants.
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Affiliation(s)
- Jayant Iyer
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz 8010, Austria
| | - Matilde Barbosa
- iMed.ULisboa, Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, Lisboa P-1649-003, Portugal
| | - Isha Saraf
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz 8010, Austria
| | - João F Pinto
- iMed.ULisboa, Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, Lisboa P-1649-003, Portugal
| | - Amrit Paudel
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz 8010, Austria.,Graz University of Technology, Institute of Process and Particle Engineering, Graz 8010, Austria
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19
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Kuksis A, Pruzanski W. Hydrolysis of polyhydroxy polyunsaturated fatty acid-glycerophosphocholines by Group IIA, V, and X secretory phospholipases A 2. Lipids 2023; 58:3-17. [PMID: 36114729 DOI: 10.1002/lipd.12359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/30/2022] [Accepted: 08/30/2022] [Indexed: 02/04/2023]
Abstract
It is widely accepted that unesterified polyunsaturated ω-6 and ω-3 fatty acids (PUFA) are converted through various lipoxygenases, cyclooxygenases, and cytochrome P450 enzymes to a range of oxygenated derivatives (oxylipins), among which the polyhydroxides of unesterified PUFA have recently been recognized as cell signaling molecules with anti-inflammatory and pro-resolving properties, known as specialized pro-resolving mediators (SPMs). This study investigates the mono-, di-, and trihydroxy 16:0/PUFA-GPCs, and the corresponding 16:0/SPM-GPC, in plasma lipoproteins. We describe the isolation and identification of mono-, di-, and trihydroxy AA, EPA, and DHA-GPC in plasma LDL, HDL, HDL3, and acute phase HDL using normal phase LC/ESI-MS, as previously reported. The lipoproteins contained variable amounts of the polyhydroxy-PUFA-GPC (0-10 nmol/mg protein), likely the product of lipid peroxidation and the action of various lipoxygenases and cytochrome P450 enzymes on both free fatty acids and the parent GPCs. Polyhydroxy-PUFA-GPC was hydrolyzed to variable extent (20%-80%) by the different secretory phospholipases A2 (sPLA2 s), with Group IIA sPLA2 showing the lowest and Group X sPLA2 the highest activity. Surprisingly, the trihydroxy-16:0/PUFA-GPC of APHDL was largely absent, while large amounts of unidentified material had migrated in the free fatty acid elution area. The free fatty acid mass spectra were consistent with that anticipated for branched chain polyhydroxy fatty acids. There was general agreement between the masses determined by LC/ESI-MS for the polyhydroxy PUFA-GPC and the masses calculated for the GPC equivalents of resolvins, protectins, and maresins using the fatty acid structures reported in the literature.
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Affiliation(s)
- Arnis Kuksis
- Department of Biochemistry, University of Toronto, Toronto, Canada
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20
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Yoshitake J, Shibata T, Chikazawa M, Uchida K. Autoxidation of ascorbate mediates lysine N-pyrrolation. Free Radic Res 2022; 56:749-759. [PMID: 36725333 DOI: 10.1080/10715762.2023.2174865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Protein N-pyrrolation, which converts lysine residues to Nε-pyrrole-l-lysine (pyrK), is a naturally occurring covalent modification. The pyrrolated proteins have a unique property of binding to DNA-staining agents, such as SYBR Green I (SG), and anti-DNA antibodies, suggesting a physiologically relevant modification that gives rise to DNA mimic protein. These properties of pyrrolated protein are suggested to be associated with innate and autoimmune responses. Short-chain aldehydes derived from lipid peroxidation are thought to be involved in the formation of pyrK. We now report that similar lysine N-pyrrolation also occurs during the metal-catalyzed oxidation of proteins with ascorbate. When human serum albumin (HSA) was incubated with Fe2+/ascorbate in the presence and absence of docosahexaenoic acid, the protein was converted to SG-binding proteins even without the polyunsaturated fatty acid. The formation of SG-binding proteins by Fe2+/ascorbate was accompanied by the formation of pyrK, which was also detected in ascorbate-treated hemoglobin. Moreover, the metal-catalyzed oxidation of ascorbate produced the pyrrolation factors, glycolaldehyde and glyoxal. These results and the observations that sera from autoimmune-prone MRL-lpr mice recognized modified proteins with Fe2+/ascorbate and with glycolaldehyde/glyoxal suggest that the autoxidation of ascorbate, as well as lipid peroxidation, can be a source of autoantigenic N-pyrrolated proteins. Our findings revealed a possible function of ascorbate as an endogenous source of pyrrolated proteins and suggested that the pyrK residues generated in proteins may play a role in the innate and autoimmune responses associated with the oxidative metabolism of ascorbate.
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Affiliation(s)
- Jun Yoshitake
- Institute of Nano-Life-Systems, Institutes of Innovation for Future Society, Nagoya University, Nagoya, Japan
| | - Takahiro Shibata
- Institute of Nano-Life-Systems, Institutes of Innovation for Future Society, Nagoya University, Nagoya, Japan.,Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Miho Chikazawa
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Koji Uchida
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.,Japan Agency for Medical Research and Development, CREST, Tokyo, Japan
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21
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Koch E, Wiebel M, Löwen A, Willenberg I, Schebb NH. Characterization of the Oxylipin Pattern and Other Fatty Acid Oxidation Products in Freshly Pressed and Stored Plant Oils. J Agric Food Chem 2022; 70:12935-12945. [PMID: 36173729 DOI: 10.1021/acs.jafc.2c04987] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Enzymatic and nonenzymatic oxidation of linoleic (LA) and α-linolenic acid (ALA) during pressing and storage of plant oils leads to a variety of oxylipins. We pressed oils from flaxseeds, rapeseeds, and sunflower seeds and analyzed the oxylipin pattern in freshly pressed oils. 9-/13-Hydro(pero)xy-LA/-ALA occurred in high concentration resulting probably from lipoxygenase-catalyzed reactions as well as autoxidation and photooxidation. However, in flaxseed and rapeseed oil, the highest concentrations were found for the terminal epoxy-ALA (15(16)-EpODE) and the hardly known 15-hydroxy-LA (15-HODE, 80 mg/100 g in flaxseed oil). Oils were stored for 6 months and the peroxide value (PV) as well as oxylipin and secondary volatile aldehyde concentrations were determined. While lipid peroxidation in flaxseed oil was surprisingly low, the oxylipin concentration and PV massively increased in rapeseed oil dependent on oxygen availability. Oxylipin concentrations correlated well with the PV, while secondary volatile aldehydes did not reflect the changes of oxylipins and PVs. The comprehensive analysis of hydroxy-, epoxy-, and dihydroxy-LA/-ALA reveals new and unique insights into the composition of plant oils and ongoing oxidation processes.
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Affiliation(s)
- Elisabeth Koch
- Chair of Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Gaussstrasse 20, 42119 Wuppertal, Germany
| | - Michelle Wiebel
- Chair of Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Gaussstrasse 20, 42119 Wuppertal, Germany
| | - Ariane Löwen
- Chair of Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Gaussstrasse 20, 42119 Wuppertal, Germany
| | - Ina Willenberg
- Department of Safety and Quality of Cereals, Max Rubner-Institut (MRI) - Federal Research Institute of Nutrition and Food, Schützenberg 12, 32756 Detmold, Germany
| | - Nils Helge Schebb
- Chair of Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Gaussstrasse 20, 42119 Wuppertal, Germany
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22
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Christensen S, Groth L, Leiva-Eriksson N, Nyblom M, Bülow L. Oxidative Implications of Substituting a Conserved Cysteine Residue in Sugar Beet Phytoglobin BvPgb 1.2. Antioxidants (Basel) 2022; 11:1615. [PMID: 36009334 DOI: 10.3390/antiox11081615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/09/2022] [Accepted: 08/17/2022] [Indexed: 11/17/2022] Open
Abstract
Phytoglobins (Pgbs) are plant-originating heme proteins of the globin superfamily with varying degrees of hexacoordination. Pgbs have a conserved cysteine residue, the role of which is poorly understood. In this paper, we investigated the functional and structural role of cysteine in BvPgb1.2, a Class 1 Pgb from sugar beet (Beta vulgaris), by constructing an alanine-substituted mutant (Cys86Ala). The substitution had little impact on structure, dimerization, and heme loss as determined by X-ray crystallography, size-exclusion chromatography, and an apomyoglobin-based heme-loss assay, respectively. The substitution significantly affected other important biochemical properties. The autoxidation rate increased 16.7- and 14.4-fold for the mutant versus the native protein at 25 °C and 37 °C, respectively. Thermal stability similarly increased for the mutant by ~2.5 °C as measured by nano-differential scanning fluorimetry. Monitoring peroxidase activity over 7 days showed a 60% activity decrease in the native protein, from 33.7 to 20.2 U/mg protein. When comparing the two proteins, the mutant displayed a remarkable enzymatic stability as activity remained relatively constant throughout, albeit at a lower level, ~12 U/mg protein. This suggests that cysteine plays an important role in BvPgb1.2 function and stability, despite having seemingly little effect on its tertiary and quaternary structure.
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23
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Chen Z, Liu P, Wang W, Cao X, Liu YX, Zhang YH, Ge M. Rapid Sulfate Formation via Uncatalyzed Autoxidation of Sulfur Dioxide in Aerosol Microdroplets. Environ Sci Technol 2022; 56:7637-7646. [PMID: 35638231 DOI: 10.1021/acs.est.2c00112] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Severe winter haze events in Beijing and North China Plain are characterized by rapid production of sulfate aerosols with unresolved mechanisms. Oxidation of SO2 by O2 in the absence of metal catalysts (uncatalyzed autoxidation) represents the most ubiquitous SO2 conversion pathway in the atmosphere. However, this reaction has long been regarded as too slow to be atmospherically meaningful. This traditional view was based on the kinetic studies conducted in bulk dilute solutions that mimic cloudwater but deviate from urban aerosols. Here, we directly measure the sulfate formation rate via uncatalyzed SO2 autoxidation in single (NH4)2SO4 microdroplets, by using an aerosol optical tweezer coupled with a cavity-enhanced Raman spectroscopy technique. We find that the aqueous reaction of uncatalyzed SO2 autoxidation is accelerated by two orders of magnitude at the high ionic strength (∼36 molal) conditions in the supersaturated aerosol water. Furthermore, at acidic conditions (pH 3.5-4.5), uncatalyzed autoxidation predominately occurs on droplet surface, with a reaction rate unconstrained by SO2 solubility. With these rate enhancements, we estimate that the uncatalyzed SO2 autoxidation in aerosols can produce sulfate at a rate up to 0.20 μg m-3 hr-1, under the winter air pollution condition in Beijing.
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Affiliation(s)
- Zhe Chen
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Pai Liu
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | | | - Xue Cao
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yu-Xin Liu
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yun-Hong Zhang
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Maofa Ge
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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24
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Scurti S, Caretti D, Mollica F, Di Antonio E, Amorati R. Chain-Breaking Antioxidant and Peroxyl Radical Trapping Activity of Phenol-Coated Magnetic Iron Oxide Nanoparticles. Antioxidants (Basel) 2022; 11:antiox11061163. [PMID: 35740061 PMCID: PMC9219998 DOI: 10.3390/antiox11061163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 11/18/2022] Open
Abstract
Superparamagnetic iron oxide nanoparticles (SPION) are important materials for biomedical applications, and phenol capping is a common procedure to passivate their surface. As phenol capped SPION have been reported to behave as antioxidants, herein, we investigate the mechanism underlying this activity by studying the reaction with alkyl peroxyl (ROO•) radicals. SPION were prepared by coprecipitation of Fe(II) and Fe(III), using phenolic antioxidants (gallic acid, Trolox and nordihydroguaiaretic acid) as post-synthesis capping agents and by different purification procedures. The reactivity of ROO• was investigated by inhibited autoxidation studies, using styrene as an oxidizable substrate (solvent MeCN, 30 °C) and azo-bis(isobutyronitrile) as a radical initiator. While unprotected, bare SPION behaved as prooxidant, accelerating the O2 consumption of styrene autoxidation, phenol capping provided a variable antioxidant effect that was dependent upon the purification degree of the material. Thoroughly washed SPION, containing from 7% to 14% (w/w) of phenols, had a low reactivity toward peroxyl radicals, while SPION with a higher phenol content (46% to 55%) showed a strong radical trapping activity. Our results indicate that the antioxidant activity of phenol-capped SPION can be caused by its release in a solution of weakly bound phenols, and that purification plays a major role in determining the properties of these materials.
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Affiliation(s)
- Stefano Scurti
- Department of Industrial Chemistry “Toso Montanari”, University of Bologna, UdR INSTM of Bologna, Viale Risorgimento 4, 40136 Bologna, Italy; (S.S.); (D.C.)
| | - Daniele Caretti
- Department of Industrial Chemistry “Toso Montanari”, University of Bologna, UdR INSTM of Bologna, Viale Risorgimento 4, 40136 Bologna, Italy; (S.S.); (D.C.)
| | - Fabio Mollica
- Department of Chemistry “G. Ciamician”, University of Bologna, Via San Giacomo 11, 40126 Bologna, Italy; (F.M.); (E.D.A.)
| | - Erika Di Antonio
- Department of Chemistry “G. Ciamician”, University of Bologna, Via San Giacomo 11, 40126 Bologna, Italy; (F.M.); (E.D.A.)
| | - Riccardo Amorati
- Department of Chemistry “G. Ciamician”, University of Bologna, Via San Giacomo 11, 40126 Bologna, Italy; (F.M.); (E.D.A.)
- Correspondence:
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25
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Valent I, Bednárová L, Schreiber I, Bujdák J, Valachová K, Šoltés L. Reaction of N-Acetylcysteine with Cu(2+): Appearance of Intermediates with High Free Radical Scavenging Activity: Implications for Anti-/Pro-Oxidant Properties of Thiols. Int J Mol Sci 2022; 23. [PMID: 35682881 DOI: 10.3390/ijms23116199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 05/27/2022] [Accepted: 05/30/2022] [Indexed: 11/16/2022] Open
Abstract
We studied the kinetics of the reaction of N-acetyl-l-cysteine (NAC or RSH) with cupric ions at an equimolar ratio of the reactants in aqueous acid solution (pH 1.4−2) using UV/Vis absorption and circular dichroism (CD) spectroscopies. Cu2+ showed a strong catalytic effect on the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) radical (ABTSr) consumption and autoxidation of NAC. Difference spectra revealed the formation of intermediates with absorption maxima at 233 and 302 nm (ε302/Cu > 8 × 103 M−1 cm−1) and two positive Cotton effects centered at 284 and 302 nm. These intermediates accumulate during the first, O2-independent, phase of the NAC autoxidation. The autocatalytic production of another chiral intermediate, characterized by two positive Cotton effects at 280 and 333 nm and an intense negative one at 305 nm, was observed in the second reaction phase. The intermediates are rapidly oxidized by added ABTSr; otherwise, they are stable for hours in the reaction solution, undergoing a slow pH- and O2-dependent photosensitive decay. The kinetic and spectral data are consistent with proposed structures of the intermediates as disulfide-bridged dicopper(I) complexes of types cis-/trans-CuI2(RS)2(RSSR) and CuI2(RSSR)2. The electronic transitions observed in the UV/Vis and CD spectra are tentatively attributed to Cu(I) → disulfide charge transfer with an interaction of the transition dipole moments (exciton coupling). The catalytic activity of the intermediates as potential O2 activators via Cu(II) peroxo-complexes is discussed. A mechanism for autocatalytic oxidation of Cu(I)−thiolates promoted by a growing electronically coupled −[CuI2(RSSR)]n− polymer is suggested. The obtained results are in line with other reported observations regarding copper-catalyzed autoxidation of thiols and provide new insight into these complicated, not yet fully understood systems. The proposed hypotheses point to the importance of the Cu(I)−disulfide interaction, which may have a profound impact on biological systems.
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26
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Rontani JF. Use of Gas Chromatography-Mass Spectrometry Techniques (GC-MS, GC-MS/MS and GC-QTOF) for the Characterization of Photooxidation and Autoxidation Products of Lipids of Autotrophic Organisms in Environmental Samples. Molecules 2022; 27:molecules27051629. [PMID: 35268730 PMCID: PMC8911584 DOI: 10.3390/molecules27051629] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/04/2022] [Accepted: 02/27/2022] [Indexed: 01/21/2023]
Abstract
This paper reviews applications of gas chromatography-mass spectrometry techniques for the characterization of photooxidation and autoxidation products of lipids of senescent phototrophic organisms. Particular attention is given to: (i) the selection of oxidation products that are sufficiently stable under environmental conditions and specific to each lipid class and degradation route; (ii) the description of electron ionization mass fragmentation of trimethylsilyl derivatives of these compounds; and (iii) the use of specific fragment ions for monitoring the oxidation of the main unsaturated lipid components of phototrophs. The techniques best geared for this task were gas chromatography-quadrupole-time of flight to monitor fragment ions with very high resolution and accuracy, and gas chromatography-tandem mass spectrometry to monitor very selective transitions in multiple reaction monitoring mode. The extent of the degradation processes can only be estimated if the oxidation products are unaffected by fast secondary oxidation reactions, as it is notably the case of ∆5-sterols, monounsaturated fatty acids, chlorophyll phytyl side-chain, and di- and triterpenoids. In contrast, the primary degradation products of highly branched isoprenoid alkenes possessing more than one trisubstituted double bond, alkenones, carotenoids and polyunsaturated fatty acids, appear to be too unstable with respect to secondary oxidation or other reactions to serve for quantification in environmental samples.
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Affiliation(s)
- Jean-François Rontani
- Mediterranean Institute of Oceanography (MIO), Aix Marseille University, Université de Toulon, CNRS, IRD, UM 110, 13288 Marseille, France
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27
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D’Ambro EL, Hyttinen N, Møller KH, Iyer S, Otkjær RV, Bell DM, Liu J, Lopez-Hilfiker FD, Schobesberger S, Shilling JE, Zelenyuk A, Kjaergaard HG, Thornton JA, Kurtén T. Pathways to Highly Oxidized Products in the Δ3-Carene + OH System. Environ Sci Technol 2022; 56:2213-2224. [PMID: 35119266 PMCID: PMC8956127 DOI: 10.1021/acs.est.1c06949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Oxidation of the monoterpene Δ3-carene (C10H16) is a potentially important and understudied source of atmospheric secondary organic aerosol (SOA). We present chamber-based measurements of speciated gas and particle phases during photochemical oxidation of Δ3-carene. We find evidence of highly oxidized organic molecules (HOMs) in the gas phase and relatively low-volatility SOA dominated by C7-C10 species. We then use computational methods to develop the first stages of a Δ3-carene photochemical oxidation mechanism and explain some of our measured compositions. We find that alkoxy bond scission of the cyclohexyl ring likely leads to efficient HOM formation, in line with previous studies. We also find a surprising role for the abstraction of primary hydrogens from methyl groups, which has been calculated to be rapid in the α-pinene system, and suggest more research is required to determine if this is more general to other systems and a feature of autoxidation. This work develops a more comprehensive view of Δ3-carene photochemical oxidation products via measurements and lays out a suggested mechanism of oxidation via computationally derived rate coefficients.
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Affiliation(s)
- Emma L. D’Ambro
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
- Department
of Chemistry, University of Helsinki, Helsinki FI-00014, Finland
| | - Noora Hyttinen
- Department
of Chemistry, University of Helsinki, Helsinki FI-00014, Finland
- Institute
for Atmospheric and Earth System Research (INAR), University of Helsinki, Helsinki FI-00014, Finland
| | - Kristian H. Møller
- Department
of Chemistry, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Siddharth Iyer
- Department
of Chemistry, University of Helsinki, Helsinki FI-00014, Finland
- Institute
for Atmospheric and Earth System Research (INAR), University of Helsinki, Helsinki FI-00014, Finland
| | - Rasmus V. Otkjær
- Department
of Chemistry, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - David M. Bell
- Atmospheric
Sciences and Global Change Division, Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | - Jiumeng Liu
- Atmospheric
Sciences and Global Change Division, Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | - Felipe D. Lopez-Hilfiker
- Department
of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, United States
| | - Siegfried Schobesberger
- Department
of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, United States
| | - John E. Shilling
- Atmospheric
Sciences and Global Change Division, Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | - Alla Zelenyuk
- Atmospheric
Sciences and Global Change Division, Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | | | - Joel A. Thornton
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
- Department
of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, United States
| | - Theo Kurtén
- Department
of Chemistry, University of Helsinki, Helsinki FI-00014, Finland
- Institute
for Atmospheric and Earth System Research (INAR), University of Helsinki, Helsinki FI-00014, Finland
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28
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Saraf I, Roskar R, Modhave D, Brunsteiner M, Karn A, Neshchadin D, Gescheidt G, Paudel A. Forced Solid-State Oxidation Studies of Nifedipine-PVP Amorphous Solid Dispersion. Mol Pharm 2022; 19:568-583. [PMID: 35060741 DOI: 10.1021/acs.molpharmaceut.1c00678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the present study, the oxidative degradation behavior of nifedipine (NIF) in amorphous solid dispersions (ASDs) prepared with poly(vinyl pyrrolidone) (PVP) with a short (K30) and a long (K90) chain length was investigated. The ASDs were prepared via dry ball-milling and analyzed using Fourier transform infrared (IR) spectroscopy, X-ray scattering, and differential scanning calorimetry. The ASDs were exposed to accelerated thermal-oxidative conditions using a pressurized oxygen headspace (120 °C for 1 day) and high temperatures at atmospheric pressure (60-120 °C for a period of 42 days). Additionally, solution-state oxidative degradation studies showed that pure NIF degrades to a greater extent than in the presence of PVP. Electronic structure calculations were performed to understand the impact of drug-polymer intermolecular interactions on the autoxidation of drugs. While no drug degradation was observed in freshly prepared ASD samples, alkyl free radicals were detected via electron paramagnetic resonance (EPR) spectroscopy. The free radicals were found to be consumed to a greater extent by PVP K30- than PVP K90-based ASDs upon exposure to high oxygen pressures. This was consistent with the greater solid-state oxidative degradation of NIF observed in ASDs with PVP K30 than with PVP K90. As no drug recrystallization occurred during this study period, the lower glass-transition temperature and presumed greater molecular mobility of PVP K30 and its ASD as compared to the PVP K90 system appear to contribute to the greater drug degradation in PVP-K30-based ASDs. The extent and the rate of oxidative degradation were higher in the case of PVP-K30-based ASD as compared to that in PVP-K90-based ASD, and the overall degradation increased with an increase in temperature. IR spectral analysis of drug-polymer interactions supports the electronic calculations of the oxidation process. We infer that, apart from the initial free radical content, the difference in the extent of drug-polymer intermolecular interactions in ASDs and amorphous stabilization during the forced oxidation experiments contribute to the observed differences in the autoxidative reactivity of the drug in ASDs with different PVP chain lengths. Overall, the chemical degradation of NIF in ASDs with two PVP chain lengths obtained from accelerated solid-state oxidation studies was in qualitative agreement with that obtained from long-term (3 years) storage under ambient conditions. The study highlights the ability of accelerated processes to determine the oxidative degradation behavior of polymeric ASDs and suggests that the polymer chain length could factor into chemical as well as physical stability considerations.
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Affiliation(s)
- Isha Saraf
- Research Center Pharmaceutical Engineering (RCPE) GmbH, Inffeldgasse 13, 8010 Graz, Austria
| | - Robert Roskar
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, 1000 Ljubljana, Slovenia
| | - Dattatray Modhave
- Research Center Pharmaceutical Engineering (RCPE) GmbH, Inffeldgasse 13, 8010 Graz, Austria
| | - Michael Brunsteiner
- Research Center Pharmaceutical Engineering (RCPE) GmbH, Inffeldgasse 13, 8010 Graz, Austria
| | - Anjali Karn
- Research Center Pharmaceutical Engineering (RCPE) GmbH, Inffeldgasse 13, 8010 Graz, Austria.,Institute for Process and Particle Engineering, Graz University of Technology, Inffeldgasse 13, 8010 Graz, Austria
| | - Dmytro Neshchadin
- Graz University of Technology, Institute of Physical and Theoretical Chemistry, Stremayrgasse 9, 8010 Graz, Austria
| | - Georg Gescheidt
- Graz University of Technology, Institute of Physical and Theoretical Chemistry, Stremayrgasse 9, 8010 Graz, Austria
| | - Amrit Paudel
- Research Center Pharmaceutical Engineering (RCPE) GmbH, Inffeldgasse 13, 8010 Graz, Austria.,Institute for Process and Particle Engineering, Graz University of Technology, Inffeldgasse 13, 8010 Graz, Austria
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29
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Kuksis A, Pruzanski W. Destruction of polyunsaturated alkyl/acyl and alkenyl/acyl glycerophosphocholine of plasma lipoproteins during incubation with group V and X secretory phospholipase A 2 s. Lipids 2021; 57:91-104. [PMID: 34904243 DOI: 10.1002/lipd.12333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 11/08/2022]
Abstract
Plasma lipoproteins are carriers of various glycerophospholipids including diacyl, alkenyl/acyl, and alkyl/acyl glycerophosphocholines (GPCs), which become distributed among cells and tissues during metabolism. For metabolic function, these phospholipids require hydrolysis by phospholipases, but the responsible enzymes have not been identified. We had previously shown that after complete digestion of lipoprotein diacyl- and oxo-diacyl-GPCs, degradation of residual alkyl/acyl and alkenyl/acyl GPCs continues, despite the fact that ether lipids are resistant to hydrolysis by Ca2+ -activated secretory PLA2 s and require the presence of the Ca2+ -independent PLA2 . In the course of further investigation, we came across a report by Khaselev and Murphy in which the autoxidative degradation of plasmalogens in the presence of 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) proceeded beyond the formation of dihydroperoxides, hydroxides and epoxides, and led to an attack on the enyl bond of the plasmalogen, resulting in formation of 1-OH/2-20:4-GPC and 1-formyl/2-20:4-GPC. Our preliminary investigation indicated that lipoprotein 16:0p/20:4ω6-GPC yielded the same autoxidation products as those reported for synthetic 16:0p/20:4ω6-GPC in the presence of AAPH. Such autoxidative degradation of lipoprotein plasmalogens had not been previously reported with or without AAPH. Subsequent study led to the conclusion that this reaction was not limited to arachidonates, but extended to other polyunsaturated eicosanoids, docosanoids, and tetracosanoids, as well as oligounsaturated octadecanoids. These observations led to a hypothesis that the autoxidative cleavage of the lipoprotein plasmalogens proceeded under the influence of apo-protein-derived free radicals as intermediates of oxidative processes.
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Affiliation(s)
- Arnis Kuksis
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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30
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Singh A, Mittal A, Benjakul S. Undesirable discoloration in edible fish muscle: Impact of indigenous pigments, chemical reactions, processing, and its prevention. Compr Rev Food Sci Food Saf 2021; 21:580-603. [PMID: 34859577 DOI: 10.1111/1541-4337.12866] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 10/06/2021] [Accepted: 10/17/2021] [Indexed: 12/17/2022]
Abstract
Fish is rich in proteins and lipids, especially those containing polyunsaturated fatty acids, which made them vulnerable to chemical or microbial changes associated with quality loss. Meat color is one of vital criteria indicating the freshness, quality, and acceptability of the meat. Color of meat is governed by the presence of various pigments such as hemoglobin, myoglobin (Mb), and so on. Mb, particularly oxy-form, is responsible for the bright red color of fish muscle, especially tuna, and dark fleshed fish, while astaxanthin (AXT) directly determines the color of salmonids muscle. Microbial spoilage and chemical changes such as oxidation of lipid/proteins result in the autoxidation of Mb or fading of AXT, leading to undesirable color with lower acceptability. The discoloration has been affected by chemical composition, post-harvesting handling or storage, processing, cooking, and so on . To tackle discoloration of fish meat, vacuum or modified atmospheric packaging, low- or ultralow-temperature storage, uses of artificial and natural additives have been employed. This review article provides information regarding the factors affecting color and other quality aspects of fish muscle. Moreover, promising methodologies used to control discoloration are also focused.
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Affiliation(s)
- Avtar Singh
- International Center of Excellence in Seafood Science and Innovation, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Ajay Mittal
- International Center of Excellence in Seafood Science and Innovation, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Soottawat Benjakul
- International Center of Excellence in Seafood Science and Innovation, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla, Thailand
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31
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Zhou X, Iqbal A, Li J, Liu C, Murtaza A, Xu X, Pan S, Hu W. Changes in Browning Degree and Reducibility of Polyphenols during Autoxidation and Enzymatic Oxidation. Antioxidants (Basel) 2021; 10:1809. [PMID: 34829680 PMCID: PMC8615057 DOI: 10.3390/antiox10111809] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/06/2021] [Accepted: 11/09/2021] [Indexed: 12/21/2022] Open
Abstract
In the present study, the browning degree and reducing power of browning products of catechin (CT), epicatechin (EC), caffeic acid (CA), and chlorogenic acid (CGA) in autoxidation and enzymatic oxidation were investigated. Influencing factors were considered, such as pH, substrate species and composition, and eugenol. Results show that polyphenols' autoxidation was intensified in an alkaline environment, but the reducing power was not improved. Products of enzymatic oxidation at a neutral pH have higher reducing power than autoxidation. In enzymatic oxidation, the browning degree of mixed substrates was higher than that of a single polyphenol. The reducing power of flavonoid mixed solution (CT and EC) was higher than those of phenolic acids' (CA and CGA) in autoxidation and enzymatic oxidation. Eugenol activity studies have shown that eugenol could increase autoxidation browning but inhibit enzymatic browning. Activity test and molecular docking results show that eugenol could inhibit tyrosinase.
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Affiliation(s)
- Xuan Zhou
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (A.I.); (J.L.); (C.L.); (A.M.); (X.X.); (S.P.)
- Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Ministry of Education, Wuhan 430070, China
| | - Aamir Iqbal
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (A.I.); (J.L.); (C.L.); (A.M.); (X.X.); (S.P.)
- Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Ministry of Education, Wuhan 430070, China
- College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Jiaxing Li
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (A.I.); (J.L.); (C.L.); (A.M.); (X.X.); (S.P.)
- Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Ministry of Education, Wuhan 430070, China
| | - Chang Liu
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (A.I.); (J.L.); (C.L.); (A.M.); (X.X.); (S.P.)
- Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Ministry of Education, Wuhan 430070, China
| | - Ayesha Murtaza
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (A.I.); (J.L.); (C.L.); (A.M.); (X.X.); (S.P.)
- Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Ministry of Education, Wuhan 430070, China
| | - Xiaoyun Xu
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (A.I.); (J.L.); (C.L.); (A.M.); (X.X.); (S.P.)
- Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Ministry of Education, Wuhan 430070, China
| | - Siyi Pan
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (A.I.); (J.L.); (C.L.); (A.M.); (X.X.); (S.P.)
- Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Ministry of Education, Wuhan 430070, China
| | - Wanfeng Hu
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (A.I.); (J.L.); (C.L.); (A.M.); (X.X.); (S.P.)
- Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Ministry of Education, Wuhan 430070, China
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32
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Baschieri A, Amorati R. Methods to Determine Chain-Breaking Antioxidant Activity of Nanomaterials beyond DPPH •. A Review. Antioxidants (Basel) 2021; 10:1551. [PMID: 34679687 PMCID: PMC8533328 DOI: 10.3390/antiox10101551] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 12/15/2022] Open
Abstract
This review highlights the progress made in recent years in understanding the mechanism of action of nanomaterials with antioxidant activity and in the chemical methods used to evaluate their activity. Nanomaterials represent one of the most recent frontiers in the research for improved antioxidants, but further development is hampered by a poor characterization of the ''antioxidant activity'' property and by using oversimplified chemical methods. Inhibited autoxidation experiments provide valuable information about the interaction with the most important radicals involved in the lipid oxidation, namely alkylperoxyl and hydroperoxyl radicals, and demonstrate unambiguously the ability to stop the oxidation of organic materials. It is proposed that autoxidation methods should always complement (and possibly replace) the use of assays based on the quenching of stable radicals (such as DPPH• and ABTS•+). The mechanisms leading to the inhibition of the autoxidation (sacrificial and catalytic radical trapping antioxidant activity) are described in the context of nanoantioxidants. Guidelines for the selection of the appropriate testing conditions and of meaningful kinetic analysis are also given.
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Affiliation(s)
- Andrea Baschieri
- Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche (ISOF-CNR), Via P. Gobetti 101, 40129 Bologna, Italy;
| | - Riccardo Amorati
- Department of Chemistry “G. Ciamician”, University of Bologna, Via S. Giacomo 11, 40126 Bologna, Italy
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Metzler-Zebeli BU. The Role of Dietary and Microbial Fatty Acids in the Control of Inflammation in Neonatal Piglets. Animals (Basel) 2021; 11:ani11102781. [PMID: 34679802 PMCID: PMC8532928 DOI: 10.3390/ani11102781] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 09/20/2021] [Accepted: 09/20/2021] [Indexed: 11/22/2022] Open
Abstract
Simple Summary The maturation of the gut is a specific and very dynamic process in new-born piglets. Consequently, piglet’s gut is very susceptible to disturbances, especially in stressful periods of life, such as weaning, when the gut lining often becomes inflamed and leaky. Dietary fatty acids (FA) do not only serve as source of energy and essential FA, but they are important precursors for bioactive lipid mediators, which modulate inflammatory signalling in the body. The current review summarizes results on dietary sources of FA for piglets, the signalling cascades, bioactivities, the necessity to consider the autoxidation potential of polyunsaturated FA and the area of microbially produced long-chain FA. That said, porcine milk is high in fat, whereby the milk FA composition partly depends on the dietary FA composition of the sow. Therefore, manipulation of the sow diet is an efficient tool to increase the piglet’s intake of specific FA, e.g., n-3 polyunsaturated FA which show anti-inflammatory activity and may support intestinal integrity and functioning in the growing animal. Abstract Excessive inflammation and a reduced gut mucosal barrier are major causes for gut dysfunction in piglets. The fatty acid (FA) composition of the membrane lipids is crucial for mediating inflammatory signalling and is largely determined by their dietary intake. Porcine colostrum and milk are the major sources of fat in neonatal piglets. Both are rich in fat, demonstrating the dependence of the young metabolism from fat and providing the young organism with the optimum profile of lipids for growth and development. The manipulation of sow’s dietary polyunsaturated FA (PUFA) intake has been shown to be an efficient strategy to increase the transfer of specific FAs to the piglet for incorporation in enteric tissues and cell membranes. n-3 PUFAs, especially seems to be beneficial for the immune response and gut epithelial barrier function, supporting the piglet’s enteric defences in situations of increased stress such as weaning. Little is known about microbial lipid mediators and their role in gut barrier function and inhibition of inflammation in neonatal piglets. The present review summarizes the current knowledge of lipid nutrition in new-born piglets, comparing the FA ingestion from milk and plant-based lipid sources and touching the areas of host lipid signalling, inflammatory signalling and microbially derived FAs.
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Affiliation(s)
- Barbara U Metzler-Zebeli
- Unit Nutritional Physiology, Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria
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Sakalauskas A, Ziaunys M, Snieckute R, Smirnovas V. Autoxidation Enhances Anti-Amyloid Potential of Flavone Derivatives. Antioxidants (Basel) 2021; 10:antiox10091428. [PMID: 34573060 PMCID: PMC8465893 DOI: 10.3390/antiox10091428] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/31/2021] [Accepted: 09/01/2021] [Indexed: 02/07/2023] Open
Abstract
The increasing prevalence of amyloid-related disorders, such as Alzheimer's or Parkinson's disease, raises the need for effective anti-amyloid drugs. It has been shown on numerous occasions that flavones, a group of naturally occurring anti-oxidants, can impact the aggregation process of several amyloidogenic proteins and peptides, including amyloid-beta. Due to flavone autoxidation at neutral pH, it is uncertain if the effective inhibitor is the initial molecule or a product of this reaction, as many anti-amyloid assays attempt to mimic physiological conditions. In this work, we examine the aggregation-inhibiting properties of flavones before and after they are oxidized. The oxidation of flavones was monitored by measuring the UV-vis absorbance spectrum change over time. The protein aggregation kinetics were followed by measuring the amyloidophilic dye thioflavin-T (ThT) fluorescence intensity change. Atomic force microscopy was employed to image the aggregates formed with the most prominent inhibitors. We demonstrate that flavones, which undergo autoxidation, have a far greater potency at inhibiting the aggregation of both the disease-related amyloid-beta, as well as a model amyloidogenic protein-insulin. Oxidized 6,2',3'-trihydroxyflavone was the most potent inhibitor affecting both insulin (7-fold inhibition) and amyloid-beta (2-fold inhibition). We also show that this tendency to autoxidize is related to the positions of the flavone hydroxyl groups.
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Ren D, Kim M, Wang SA, Liu HW. Identification of a Pyrrole Intermediate Which Undergoes C-Glycosidation and Autoxidation to Yield the Final Product in Showdomycin Biosynthesis. Angew Chem Int Ed Engl 2021; 60:17148-17154. [PMID: 34048627 DOI: 10.1002/anie.202105667] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Indexed: 02/04/2023]
Abstract
Showdomycin is a C-nucleoside bearing an electrophilic maleimide base. Herein, the biosynthetic pathway of showdomycin is presented. The initial stages of the pathway involve non-ribosomal peptide synthetase (NRPS) mediated assembly of a 2-amino-1H-pyrrole-5-carboxylic acid intermediate. This intermediate is prone to air oxidation whereupon it undergoes oxidative decarboxylation to yield an imine of maleimide, which in turn yields the maleimide upon acidification. It is also shown that this pyrrole intermediate serves as the substrate for the C-glycosidase SdmA in the pathway. After coupling with ribose 5-phosphate, the resulting C-nucleoside undergoes a similar sequence of oxidation, decarboxylation and deamination to afford showdomcyin after exposure to air. These results suggest that showdomycin could be an artifact due to aerobic isolation; however, the autoxidation may also serve to convert an otherwise inert product of the biosynthetic pathway to an electrophilic C-nucleotide thereby endowing showdomycin with its observed bioactivities.
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Affiliation(s)
- Daan Ren
- Department of Chemistry, Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX, 78712, USA
| | - Minje Kim
- Department of Chemistry, Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX, 78712, USA
| | - Shao-An Wang
- Department of Chemistry, Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX, 78712, USA
| | - Hung-Wen Liu
- Department of Chemistry, Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX, 78712, USA
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Yuasa HJ, Stocker R. Methylene blue and ascorbate interfere with the accurate determination of the kinetic properties of IDO2. FEBS J 2021; 288:4892-4904. [PMID: 33686747 DOI: 10.1111/febs.15806] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 02/16/2021] [Accepted: 03/08/2021] [Indexed: 11/30/2022]
Abstract
Indoleamine 2,3-dioxygenases (IDOs) catalyze the oxidative cleavage of L-tryptophan (Trp) to N-formylkynurenine. Two IDOs, IDO1 and IDO2, are present in vertebrates. IDO1 is a high-affinity Trp-degrading enzyme involved in several physiological processes. By comparison, IDO2 generally has been reported to have low affinity (high Km -value) for Trp, and the enzyme's in vivo function remains unclear. Using IDOs from different species, we show that compared with ferrous-oxy (Fe2+ -O2 ) IDO1, Fe2+ -O2 IDO2 is substantially more stable and engages in multiple turnovers of the reaction in the absence of a reductant. Without reductant, Fe2+ -O2 IDO2 showed Km -values in the range of 80-356 μM, that is, values substantially lower than reported previously and close to the physiological concentrations of Trp. Methylene blue and ascorbate (Asc), used commonly as the reducing system for IDO activity determination, significantly affected the enzymatic activity of IDO2: In combination, the two reductants increased the apparent Km - and kcat -values 8- to 117-fold and 2-fold, respectively. Asc alone both activated and inhibited IDO2 by acting as a source of electrons and as a weak competitive inhibitor, respectively. In addition, ferric (Fe3+ ) IDO1 and IDO2 exhibited weak dioxygenase activity, similar to tryptophan 2,3-dioxygenase. Our results shed new light in the enzymatic activity of IDO2, and they support the view that this isoform of IDO also participates in the metabolism of Trp in vivo.
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Affiliation(s)
- Hajime J Yuasa
- Laboratory of Biochemistry, Department of Chemistry and Biotechnology, Faculty of Science and Technology, National University Corporation Kochi University, Japan
| | - Roland Stocker
- Arterial Inflammation and Redox Biology Group, Heart Research Institute, Newtown, NSW, Australia
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Huang ZH, Peng SW, Hsieh SL, Kirankumar R, Huang PF, Chang TM, Dwivedi AK, Chen NF, Wu HM, Hsieh S. Polydopamine Ultrathin Film Growth on Mica via In-Situ Polymerization of Dopamine with Applications for Silver-Based Antimicrobial Coatings. Materials (Basel) 2021; 14:ma14030671. [PMID: 33535625 PMCID: PMC7867202 DOI: 10.3390/ma14030671] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/26/2021] [Accepted: 01/28/2021] [Indexed: 01/06/2023]
Abstract
The development of polydopamine (PDA) coatings with a nanometer-scale thickness on surfaces is highly desirable for exploiting the novel features arising from the specific structure on the molecular level. Exploring the mechanisms of thin-film growth is helpful for attaining desirable control over the useful properties of materials. We present a systematic study demonstrating the growth of a PDA thin film on the surface of mica in consecutive short deposition time intervals. Film growth at each deposition time was monitored through instrumental techniques such as atomic force microscopy (AFM), water contact angle (WCA) analysis, and X-ray photoelectron spectroscopy (XPS). Film growth was initiated by adsorption of the PDA molecules on mica, with subsequent island-like aggregation, and finally, a complete molecular level PDA film was formed on the surface due to further molecular adsorption. A duration of 60−300 s was sufficient for complete formation of the PDA layer within the thickness range of 0.5−1.1 nm. An outstanding feature of PDA ultrathin films is their ability to act as a molecular adhesive, providing a foundation for constructing functional surfaces. We also explored antimicrobial applications by incorporating Ag nanoparticles into a PDA film. The Ag NPs/PDA film was formed on a surgical blade and then characterized and confirmed by SEM-EDS and XPS. The modified film inhibited bacterial growth by up to 42% on the blade after cutting through a pork meat sample.
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Affiliation(s)
- Zheng-Hao Huang
- Department of Rheumatology Immunology, Kaohsiung Armed Forced General Hospital, 2 Zhongzheng 1st Rd., Kaohsiung 80284, Taiwan; (Z.-H.H.); (P.-F.H.)
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan;
| | - Shi-Wei Peng
- Department of Chemistry, National Sun Yat-Sen University, 70 Lien-Hai Rd., Kaohsiung 80424, Taiwan; (S.-W.P.); (R.K.); (A.K.D.)
| | - Shu-Ling Hsieh
- Department of Seafood Science, National Kaohsiung University of Science and Technology, 142 Haijhuan Rd., Kaohsiung 81157, Taiwan;
| | - Rajendranath Kirankumar
- Department of Chemistry, National Sun Yat-Sen University, 70 Lien-Hai Rd., Kaohsiung 80424, Taiwan; (S.-W.P.); (R.K.); (A.K.D.)
| | - Po-Feng Huang
- Department of Rheumatology Immunology, Kaohsiung Armed Forced General Hospital, 2 Zhongzheng 1st Rd., Kaohsiung 80284, Taiwan; (Z.-H.H.); (P.-F.H.)
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan;
| | - Tsao-Ming Chang
- Division of Neurosurgery, Department of Surgery, Kaohsiung Armed Forces General Hospital, 2 Zhongzheng 1st Rd., Kaohsiung 80284, Taiwan;
| | - Atul Kumar Dwivedi
- Department of Chemistry, National Sun Yat-Sen University, 70 Lien-Hai Rd., Kaohsiung 80424, Taiwan; (S.-W.P.); (R.K.); (A.K.D.)
| | - Nan-Fu Chen
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan;
- Division of Neurosurgery, Department of Surgery, Kaohsiung Armed Forces General Hospital, 2 Zhongzheng 1st Rd., Kaohsiung 80284, Taiwan;
| | - Hao-Ming Wu
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Armed Forces General Hospital, 2 Zhongzheng 1st Rd., Kaohsiung 80284, Taiwan;
| | - Shuchen Hsieh
- Department of Chemistry, National Sun Yat-Sen University, 70 Lien-Hai Rd., Kaohsiung 80424, Taiwan; (S.-W.P.); (R.K.); (A.K.D.)
- School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, 100 Shih-Chuan 1st Rd., Kaohsiung 80708, Taiwan
- Regenerative Medicine and Cell Therapy Research Center, Kaohsiung Medical University, 100 Shih-Chuan 1st Rd., Kaohsiung 80708, Taiwan
- Correspondence:
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Hwang IM, Park B, Yang JS, Ha JH. Distinguishing between long-term-stored and fresh chili pepper powder through fingerprinting of volatiles by headspace capillary-gas chromatography-ion mobility spectrometry. J Food Sci 2020; 85:4359-4366. [PMID: 33216385 DOI: 10.1111/1750-3841.15538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 10/24/2020] [Accepted: 11/05/2020] [Indexed: 11/30/2022]
Abstract
Long-term storage of chili pepper powder results in physicochemical and microbiological changes that decrease its commercial value; these changes occur owing to fungal growth and production of off-flavor compounds. Herein, long-term-stored chili pepper powder (LSCPP) and fresh chili pepper powder (FCPP) were analyzed using internal transcribed spacer sequencing and volatile organic compound fingerprinting by headspace capillary-gas chromatography-ion mobility spectrometry. Fungal analysis detected only Xeromyces bisporus with high accuracy in all the analyzed LSCPP samples. However, the proliferation of X. bisporus on nonspecific spots complicated the distinguishing process between the two groups based solely on fungal analysis. Therefore, nine compounds (three ketones, one alcohol, two aldehydes, one ester, one furan, and one sulfur compound) obtained by autoxidation and fungal metabolism were selected as potential markers for distinguishing LSCPP and FCPP. These above-mentioned substances, which were confirmed as off-flavor species owing to "stale" odor, emitted lipid fragrance and were used to successfully distinguish LSCPP from FCPP using principal component analysis and linear discriminant analysis. PRACTICAL APPLICATION: According to the research results, it was possible to discriminate between long-term stored and fresh chili pepper powders using nine VOC markers for quality control in industry. In addition, the fungus generated from long-term storage of chili pepper powder was Xeromyces bisporus, which was confirmed to be safe for intake because it does not form secondary toxic metabolites.
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Affiliation(s)
- In Min Hwang
- Hygienic Safety and Analysis Center, World Institute of Kimchi, 86, Kimchi-ro, Nam-gu, Gwangju, 61755, Republic of Korea
| | - Boyeon Park
- Hygienic Safety and Analysis Center, World Institute of Kimchi, 86, Kimchi-ro, Nam-gu, Gwangju, 61755, Republic of Korea
| | - Ji-Su Yang
- Hygienic Safety and Analysis Center, World Institute of Kimchi, 86, Kimchi-ro, Nam-gu, Gwangju, 61755, Republic of Korea
| | - Ji-Hyoung Ha
- Hygienic Safety and Analysis Center, World Institute of Kimchi, 86, Kimchi-ro, Nam-gu, Gwangju, 61755, Republic of Korea
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Moussa H, Quezada E, Viña D, Riadi H, Gil-Longo J. Redox-Active Phenolic Compounds Mediate the Cytotoxic and Antioxidant Effects of Carpodesmia tamariscifolia (=Cystoseira tamariscifolia). Chem Biodivers 2020; 17:e2000121. [PMID: 32374938 DOI: 10.1002/cbdv.202000121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/06/2020] [Indexed: 12/22/2022]
Abstract
Carpodesmia tamariscifolia is a brown alga rich in (poly)phenols with important cytotoxic and antioxidant effects. However, the relationship between its chemical composition and its effects is unknown. The aim of this study is to identify the potential compounds and mechanisms responsible for its main effects. The alga was extracted consecutively with hexane, dichloromethane and methanol and further fractionated using Sephadex LH-20 and silica gel columns when appropriate. The fractions were subjected to thin-layer chromatography and liquid chromatography-mass spectrometry analysis and evaluated for their total phenolic content (Folin-Ciocalteu assay), radical scavenging activity (DPPH assay), cytotoxic activity (MTT assay on the SH-SY5Y cell line), and ability to generate H2 O2 (Amplex Red assay). Chromatographic and phenolic analyses of the fractions indicate that abundant redox-active phenols are present in all the fractions and that a high amount of prenylated hydroquinone derivatives is present in the apolar ones. In the hexane and dichloromethane fractions, the cytotoxic and antioxidant activities are closely related to their phenolic content, whereas in the methanol fractions, the cytotoxicity is negatively related to the phenolic content and the antioxidant activity is positively related to it. In the same tests, hydroquinone behaves as both strong cytotoxic and antioxidant agent. H2 O2 assay shows that C. tamariscifolia fractions and hydroquinone can autoxidize and generate H2 O2 . Our results suggest that redox-active phenols produce the pharmacological effects described for C. tamariscifolia and that the hydroquinone moiety of prenylated hydroquinone derivatives is responsible for both cytotoxic (through a pro-oxidant mechanism secondary to its autoxidation) and antioxidant effects of the apolar fractions.
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Affiliation(s)
- Hanaa Moussa
- Departamento de Farmacología, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782, Santiago de Compostela, Spain.,Present adress, Applied Phycology-Mycology Group (PMA), Applied Botany Laboratory, Department of Biology, Faculty of Sciences, Abdelmalek Essaâdi University, 93030, Tétouan, Morocco
| | - Elías Quezada
- Departamento de Química Orgánica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782, Santiago de Compostela, Spain
| | - Dolores Viña
- Farmacología de las Enfermedades Crónicas, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS), Universidad de Santiago de Compostela, 15782, Santiago de Compostela, Spain
| | - Hassane Riadi
- Applied Phycology-Mycology Group (PMA), Applied Botany Laboratory, Department of Biology, Faculty of Sciences, Abdelmalek Essaâdi University, 93030, Tétouan, Morocco
| | - José Gil-Longo
- Departamento de Farmacología, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782, Santiago de Compostela, Spain
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Antonio EN, Wicking C, Filip S, Ryan MP, Heutz S. Role of Iron Speciation in Oxidation and Deposition at the Hexadecane-Iron Interface. ACS Appl Mater Interfaces 2020; 12:19140-19152. [PMID: 32255329 DOI: 10.1021/acsami.9b22983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Interactions between iron surfaces and hydrocarbons are the basis for a wide range of materials synthesis processes and novel applications, including sensing. However, in diesel engines these interactions can lead to deposit formation that reduces performance, lowers efficiency, and increases emissions. Here, we present a global study to understand deposition at iron-hexadecane interfaces. We use a combination of spectroscopy, microscopy, and mass spectrometry to investigate surface reactions, bulk chemistry, and deposition processes. A dynamic equilibrium between the oxidation products, both at the surface and in solution, determines the deposition at the surface. Considering the solution and the surface in parallel, we find that the iron speciation affects the morphology, composition, and quantity of the deposit at the surface, as well as the oxidation of hexadecane. Fe(II) and Fe(III) both promote the decomposition of peroxides-intermediates in the oxidation of hexadecane-but through noncatalytic and catalytic mechanisms, respectively. In contrast, Fe(0) is proposed to initiate hexadecane autoxidation during its oxidation to Fe(III). We find that in all cases, the surfaces exclusively contain Fe(III) following heat treatment with hexadecane. Upon subsequent exposure at room temperature, Fe(III) species are found to promote oxidation; this finding is particularly concerning for hybrid vehicles where longer time periods are expected between engine operation. Our work provides a foundation for the development of strategies that disrupt the role of iron in the degradation of hexadecane to ultimately reduce oxidation and deposition in diesel engines.
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Affiliation(s)
- Emma N Antonio
- Department of Materials, Imperial College London, SW7 2AZ London, U.K
- London Centre for Nanotechnology, Imperial College London, SW7 2AZ London, U.K
| | - Christianne Wicking
- BP Formulated Products Technology Centre, Whitchurch Hill, Pangbourne, Reading RG8 7QR, U.K
| | - Sorin Filip
- BP Formulated Products Technology Centre, Whitchurch Hill, Pangbourne, Reading RG8 7QR, U.K
| | - Mary P Ryan
- Department of Materials, Imperial College London, SW7 2AZ London, U.K
- London Centre for Nanotechnology, Imperial College London, SW7 2AZ London, U.K
| | - Sandrine Heutz
- Department of Materials, Imperial College London, SW7 2AZ London, U.K
- London Centre for Nanotechnology, Imperial College London, SW7 2AZ London, U.K
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Veres PR, Neuman JA, Bertram TH, Assaf E, Wolfe GM, Williamson CJ, Weinzierl B, Tilmes S, Thompson CR, Thames AB, Schroder JC, Saiz-Lopez A, Rollins AW, Roberts JM, Price D, Peischl J, Nault BA, Møller KH, Miller DO, Meinardi S, Li Q, Lamarque JF, Kupc A, Kjaergaard HG, Kinnison D, Jimenez JL, Jernigan CM, Hornbrook RS, Hills A, Dollner M, Day DA, Cuevas CA, Campuzano-Jost P, Burkholder J, Bui TP, Brune WH, Brown SS, Brock CA, Bourgeois I, Blake DR, Apel EC, Ryerson TB. Global airborne sampling reveals a previously unobserved dimethyl sulfide oxidation mechanism in the marine atmosphere. Proc Natl Acad Sci U S A 2020; 117:4505-10. [PMID: 32071211 DOI: 10.1073/pnas.1919344117] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dimethyl sulfide (DMS), emitted from the oceans, is the most abundant biological source of sulfur to the marine atmosphere. Atmospheric DMS is oxidized to condensable products that form secondary aerosols that affect Earth's radiative balance by scattering solar radiation and serving as cloud condensation nuclei. We report the atmospheric discovery of a previously unquantified DMS oxidation product, hydroperoxymethyl thioformate (HPMTF, HOOCH2SCHO), identified through global-scale airborne observations that demonstrate it to be a major reservoir of marine sulfur. Observationally constrained model results show that more than 30% of oceanic DMS emitted to the atmosphere forms HPMTF. Coincident particle measurements suggest a strong link between HPMTF concentration and new particle formation and growth. Analyses of these observations show that HPMTF chemistry must be included in atmospheric models to improve representation of key linkages between the biogeochemistry of the ocean, marine aerosol formation and growth, and their combined effects on climate.
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Abstract
Autoxidation is an autocatalytic free-radical chain reaction responsible for the oxidative destruction of organic molecules in biological cells, foods, plastics, petrochemicals, fuels, and the environment. In cellular membranes, lipid autoxidation (peroxidation) is linked with oxidative stress, age-related diseases, and cancers. The established mechanism of autoxidation proceeds via H-atom abstraction through a cyclic network of peroxy-hydroperoxide-mediated free-radical chain reactions. For a series of model unsaturated lipids, we present evidence for an autoxidation mechanism, initiated by hydroxyl radical (OH) addition to C=C bonds and propagated by chain reactions involving Criegee intermediates (CIs). This mechanism leads to unexpectedly rapid autoxidation even in the presence of water, implying that as reactive intermediates, CI could play a much more prominent role in chemistries beyond the atmosphere.
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Lin Y, Koppenol WP, Knol D, Vermeer MA, Hiemstra H, Friedrichs S, Lütjohann D, Trautwein EA. Serum Concentration of Plant Sterol Oxidation Products (POP) Compared to Cholesterol Oxidation Products (COP) after Intake of Oxidized Plant Sterols: A Randomised, Placebo-Controlled, Double-Blind Dose‒Response Pilot Study. Nutrients 2019; 11:E2319. [PMID: 31575059 DOI: 10.3390/nu11102319] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 12/14/2022] Open
Abstract
Plant sterols (PS) are oxidized to PS oxidation products (POP). This study quantified the change in serum POP compared to cholesterol oxidation products (COP) after the intake of increasing POP doses. This was a double-blind, randomized, placebo-controlled, dose‒response pilot study with healthy individuals in four groups (15 per group). The control group received products with no added PS or POP and treatment groups received daily 20–25 g margarine with added PS (mean 3 g/d) and two cookies (~28 g) for six weeks. Cookies delivered 8.7 (low-dose), 15.2 (medium-dose), or 37.2 (high-dose) mg/d POP. Fasting serum POP and COP were measured at the baseline, days 14, 28, and 42 in all participants and days 7, 21, and 35 in a subset. Sixty individuals completed the study; 52 were included in per protocol analysis. Serum POP increased with increasing POP intake and plateaued at dose >15 mg/d. Stabilized POP concentrations were (mean ± SD) 38.9 ± 6.9, 91.0 ± 27.9, 144.4 ± 37.9 and 203.0 ± 63.7 nmol/L, for control, low-, medium-, and high-dose POP groups, respectively. For all groups, the serum COP ranged from 213 to 262 nmol/L and the average POP/COP ratio was <1. Serum POP concentrations increased non-linearly, reaching stabilized concentrations in <7 days, and remained below COP concentrations after the intake of increasing POP doses.
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Nozière B, Vereecken L. Direct Observation of Aliphatic Peroxy Radical Autoxidation and Water Effects: An Experimental and Theoretical Study. Angew Chem Int Ed Engl 2019; 58:13976-13982. [PMID: 31361086 DOI: 10.1002/anie.201907981] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Indexed: 11/08/2022]
Abstract
The autoxidation of organic peroxy radicals (RO2 ) into hydroperoxy-alkyl radicals (QOOH), then hydroperoxy-peroxy radicals (HOOQO2 ) is now considered to be important in the Earth's atmosphere. To avoid mechanistic uncertainties these reactions are best studied by monitoring the radicals. But for the volatile and aliphatic RO2 radicals playing key roles in the atmosphere this has long been an instrumental challenge. This work reports the first study of the autoxidation of aliphatic RO2 radicals and is based on monitoring RO2 and HOOQO2 radicals. The rate coefficients, kiso (s-1 ), were determined both experimentally and theoretically using MC-TST kinetic theory based on CCSD(T)//M06-2X quantum chemical methodologies. The results were in excellent agreement and confirmed that the first H-migration is strongly rate-limiting in the oxidation of non-oxygenated volatile organic compounds (VOCs). At higher relative humidity (2-30 %) water complexes were evidenced for HOOQO2 radicals, which could be an important fate for HOO-substituted RO2 radicals in the atmosphere.
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Affiliation(s)
- Barbara Nozière
- IRCELYON, CNRS, Université Claude Bernard Lyon 1, 2 avenue Albert Einstein, 69626, Villeurbanne, France
| | - Luc Vereecken
- Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
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Baschieri A, Pizzol R, Guo Y, Amorati R, Valgimigli L. Calibration of Squalene, p-Cymene, and Sunflower Oil as Standard Oxidizable Substrates for Quantitative Antioxidant Testing. J Agric Food Chem 2019; 67:6902-6910. [PMID: 31132263 DOI: 10.1021/acs.jafc.9b01400] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The autoxidation kinetics of stripped sunflower oil (SSO), squalene (SQ), and p-cymene ( p-C) initiated by 2,2'-azobis(isobutyronitrile) at 303 K were investigated under controlled conditions by differential oximetry in order to build reference model systems that are representative of the natural variability of oxidizable materials, for quantitative antioxidant testing. Rate constants for oxidative chain propagation ( kp) and chain termination (2 kt) and the oxidizability ( kp/√2 kt) were measured using 2,6-di- tert-butyl-4-methoxyphenol, 2,2,5,7,8-pentamethyl-6-chromanol, BHT, and 4-methoxyphenol as reference antioxidants. Measured values of kp (M-1 s-1)/2 kt (M-1 s-1)/oxidizability (M-1/2 s-1/2) at 303 K in chlorobenzene were 66.9/3.45 × 106/3.6 × 10-2, 68.0/7.40 × 106/2.5 × 10-2, and 0.83/2.87 × 106/4.9 × 10-4, respectively, for SSO, SQ, and p-C. Quercetin, magnolol, caffeic acid phenethyl ester, and 2,4,6-trimethylphenol were investigated to validate calibrations. The distinctive usefulness of the three substrates in testing antioxidants is discussed.
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Affiliation(s)
- Andrea Baschieri
- Department of Chemistry "G. Ciamician" , University of Bologna , Via S. Giacomo 11 , 40126 Bologna , Italy
| | - Romeo Pizzol
- Department of Chemistry "G. Ciamician" , University of Bologna , Via S. Giacomo 11 , 40126 Bologna , Italy
| | - Yafang Guo
- Department of Chemistry "G. Ciamician" , University of Bologna , Via S. Giacomo 11 , 40126 Bologna , Italy
| | - Riccardo Amorati
- Department of Chemistry "G. Ciamician" , University of Bologna , Via S. Giacomo 11 , 40126 Bologna , Italy
| | - Luca Valgimigli
- Department of Chemistry "G. Ciamician" , University of Bologna , Via S. Giacomo 11 , 40126 Bologna , Italy
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García-Quiles L, Valdés A, Fernández Cuello Á, Jiménez A, Garrigós MDC, Castell P. Reducing off-Flavour in Commercially Available Polyhydroxyalkanoate Materials by Autooxidation through Compounding with Organoclays. Polymers (Basel) 2019; 11:E945. [PMID: 31159321 DOI: 10.3390/polym11060945] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/28/2019] [Accepted: 05/29/2019] [Indexed: 12/03/2022] Open
Abstract
Polyhydroxyalkanoates (PHAs) are nowadays considered competent candidates to replace traditional plastics in several market sectors. However, commercial PHA materials exhibit unsatisfactory smells that can negatively affect the quality of the final product. The cause of this typical rancid odour is attributed to oxidized cell membrane glycolipids, coming from Gram-negative production strains, which remain frequently attached to PHAs granules after the extraction stage. The aim of this research is the development of customised PHA bio-nano-composites for industrial applications containing organomodified nanoclays with high adsorbance properties able to capture volatile compounds responsible for the displeasing fragrance. To this end, a methodology for the detection and identification of the key volatiles released due to oxidative degradation of PHAs has been established using a headspace solid-phase microextraction technique. We report the development of nine bio-nano-composite materials based on three types of commercial PHA matrices loaded with three species of nanoclays which represent a different polar behaviour. It has been demonstrated that although the reached outcoming effect depends on the volatile nature, natural sepiolite might result in the most versatile candidate for any the PHA matrices selected.
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Abstract
The reaction profiles for the uni- and bimolecular decomposition of benzyl hydroperoxide have been studied in the context of initiation reactions for the (aut)oxidation of hydrocarbons. The unimolecular dissociation of benzyl hydroperoxide was found to proceed through the formation of a hydrogen-bonded radical-pair minimum located +181 kJ mol-1 above the hydroperoxide substrate and around 15 kJ mol-1 below the separated radical products. The reaction of toluene with benzyl hydroperoxide proceeds such that O-O bond homolysis is coupled with a C-H bond abstraction event in a single kinetic step. The enthalpic barrier of this molecule-induced radical formation (MIRF) process is significantly lower than that of the unimolecular O-O bond cleavage. The same type of reaction is also possible in the self-reaction between two benzyl hydroperoxide molecules forming benzyloxyl and hydroxyl radical pairs along with benzaldehyde and water as co-products. In the product complexes formed in these MIRF reactions, both radicals connect to a centrally placed water molecule through hydrogen-bonding interactions.
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Affiliation(s)
- Lakshmanan Sandhiya
- Department Chemie, Ludwig-Maximilians-Universität München, 81377, München, Germany
| | - Hendrik Zipse
- Department Chemie, Ludwig-Maximilians-Universität München, 81377, München, Germany
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48
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Pye HOT, D'Ambro EL, Lee BH, Schobesberger S, Takeuchi M, Zhao Y, Lopez-Hilfiker F, Liu J, Shilling JE, Xing J, Mathur R, Middlebrook AM, Liao J, Welti A, Graus M, Warneke C, de Gouw JA, Holloway JS, Ryerson TB, Pollack IB, Thornton JA. Anthropogenic enhancements to production of highly oxygenated molecules from autoxidation. Proc Natl Acad Sci U S A 2019; 116:6641-6646. [PMID: 30886090 PMCID: PMC6452672 DOI: 10.1073/pnas.1810774116] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Atmospheric oxidation of natural and anthropogenic volatile organic compounds (VOCs) leads to secondary organic aerosol (SOA), which constitutes a major and often dominant component of atmospheric fine particulate matter (PM2.5). Recent work demonstrates that rapid autoxidation of organic peroxy radicals (RO2) formed during VOC oxidation results in highly oxygenated organic molecules (HOM) that efficiently form SOA. As NOx emissions decrease, the chemical regime of the atmosphere changes to one in which RO2 autoxidation becomes increasingly important, potentially increasing PM2.5, while oxidant availability driving RO2 formation rates simultaneously declines, possibly slowing regional PM2.5 formation. Using a suite of in situ aircraft observations and laboratory studies of HOM, together with a detailed molecular mechanism, we show that although autoxidation in an archetypal biogenic VOC system becomes more competitive as NOx decreases, absolute HOM production rates decrease due to oxidant reductions, leading to an overall positive coupling between anthropogenic NOx and localized biogenic SOA from autoxidation. This effect is observed in the Atlanta, Georgia, urban plume where HOM is enhanced in the presence of elevated NO, and predictions for Guangzhou, China, where increasing HOM-RO2 production coincides with increases in NO from 1990 to 2010. These results suggest added benefits to PM2.5 abatement strategies come with NOx emission reductions and have implications for aerosol-climate interactions due to changes in global SOA resulting from NOx interactions since the preindustrial era.
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Affiliation(s)
- Havala O T Pye
- National Exposure Research Laboratory, Environmental Protection Agency, Research Triangle Park, NC 27711;
- Department of Atmospheric Science, University of Washington, Seattle, WA 98195
| | - Emma L D'Ambro
- Department of Atmospheric Science, University of Washington, Seattle, WA 98195
- Department of Chemistry, University of Washington, Seattle, WA 98195
| | - Ben H Lee
- Department of Atmospheric Science, University of Washington, Seattle, WA 98195
| | - Siegfried Schobesberger
- Department of Atmospheric Science, University of Washington, Seattle, WA 98195
- Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland
| | - Masayuki Takeuchi
- National Exposure Research Laboratory, Environmental Protection Agency, Research Triangle Park, NC 27711
| | - Yue Zhao
- Department of Atmospheric Science, University of Washington, Seattle, WA 98195
| | | | - Jiumeng Liu
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA 99352
| | - John E Shilling
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Jia Xing
- National Exposure Research Laboratory, Environmental Protection Agency, Research Triangle Park, NC 27711
| | - Rohit Mathur
- National Exposure Research Laboratory, Environmental Protection Agency, Research Triangle Park, NC 27711
| | - Ann M Middlebrook
- Chemical Sciences Division, National Oceanic and Atmospheric Administration Earth System Research Laboratory, Boulder, CO 80305
| | - Jin Liao
- Chemical Sciences Division, National Oceanic and Atmospheric Administration Earth System Research Laboratory, Boulder, CO 80305
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309
| | - André Welti
- Chemical Sciences Division, National Oceanic and Atmospheric Administration Earth System Research Laboratory, Boulder, CO 80305
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309
| | - Martin Graus
- Chemical Sciences Division, National Oceanic and Atmospheric Administration Earth System Research Laboratory, Boulder, CO 80305
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309
| | - Carsten Warneke
- Chemical Sciences Division, National Oceanic and Atmospheric Administration Earth System Research Laboratory, Boulder, CO 80305
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309
| | - Joost A de Gouw
- Chemical Sciences Division, National Oceanic and Atmospheric Administration Earth System Research Laboratory, Boulder, CO 80305
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309
| | - John S Holloway
- Chemical Sciences Division, National Oceanic and Atmospheric Administration Earth System Research Laboratory, Boulder, CO 80305
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309
| | - Thomas B Ryerson
- Chemical Sciences Division, National Oceanic and Atmospheric Administration Earth System Research Laboratory, Boulder, CO 80305
| | - Ilana B Pollack
- Chemical Sciences Division, National Oceanic and Atmospheric Administration Earth System Research Laboratory, Boulder, CO 80305
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309
| | - Joel A Thornton
- Department of Atmospheric Science, University of Washington, Seattle, WA 98195;
- Department of Chemistry, University of Washington, Seattle, WA 98195
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Rissanen MP. NO 2 Suppression of Autoxidation-Inhibition of Gas-Phase Highly Oxidized Dimer Product Formation. ACS Earth Space Chem 2018; 2:1211-1219. [PMID: 30488044 PMCID: PMC6251564 DOI: 10.1021/acsearthspacechem.8b00123] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/10/2018] [Accepted: 10/12/2018] [Indexed: 06/09/2023]
Abstract
Atmospheric autoxidation of volatile organic compounds (VOC) leads to prompt formation of highly oxidized multifunctional compounds (HOM) that have been found crucial in forming ambient secondary organic aerosol (SOA). As a radical chain reaction mediated by oxidized peroxy (RO2) and alkoxy (RO) radical intermediates, the formation pathways can be intercepted by suitable reaction partners, preventing the production of the highest oxidized reaction products, and thus the formation of the most condensable material. Commonly, NO is expected to have a detrimental effect on RO2 chemistry, and thus on autoxidation, whereas the influence of NO2 is mostly neglected. Here it is shown by dedicated flow tube experiments, how high concentration of NO2 suppresses cyclohexene ozonolysis initiated autoxidation chain reaction. Importantly, the addition of NO2 ceases covalently bound dimer production, indicating their production involving acylperoxy radical (RC(O)OO•) intermediates. In related experiments NO was also shown to strongly suppress the highly oxidized product formation, but due to possibility for chain propagating reactions (as with RO2 and HO2 too), the suppression is not as absolute as with NO2. Furthermore, it is shown how NO x reactions with oxidized peroxy radicals lead into indistinguishable product compositions, complicating mass spectral assignments in any RO2 + NO x system. The present work was conducted with atmospheric pressure chemical ionization mass spectrometry (CIMS) as the detection method for the highly oxidized end-products and peroxy radical intermediates, under ambient conditions and at short few second reaction times. Specifically, the insight was gained by addition of a large amount of NO2 (and NO) to the oxidation system, upon which acylperoxy radicals reacted in RC(O)O2 + NO2 → RC(O)O2NO2 reaction to form peroxyacylnitrates, consequently shutting down the oxidation sequence.
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Affiliation(s)
- Matti P. Rissanen
- Institute for Atmospheric
and Earth System Research (INAR), University
of Helsinki, Helsinki, Finland
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50
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Zhao Y, Thornton JA, Pye HOT. Quantitative constraints on autoxidation and dimer formation from direct probing of monoterpene-derived peroxy radical chemistry. Proc Natl Acad Sci U S A 2018; 115:12142-7. [PMID: 30413618 DOI: 10.1073/pnas.1812147115] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Organic peroxy radicals (RO2) are key intermediates in the atmospheric degradation of organic matter and fuel combustion, but to date, few direct studies of specific RO2 in complex reaction systems exist, leading to large gaps in our understanding of their fate. We show, using direct, speciated measurements of a suite of RO2 and gas-phase dimers from O3-initiated oxidation of α-pinene, that ∼150 gaseous dimers (C16-20H24-34O4-13) are primarily formed through RO2 cross-reactions, with a typical rate constant of 0.75-2 × 10-12 cm3 molecule-1 s-1 and a lower-limit dimer formation branching ratio of 4%. These findings imply a gaseous dimer yield that varies strongly with nitric oxide (NO) concentrations, of at least 0.2-2.5% by mole (0.5-6.6% by mass) for conditions typical of forested regions with low to moderate anthropogenic influence (i.e., ≤50-parts per trillion NO). Given their very low volatility, the gaseous C16-20 dimers provide a potentially important organic medium for initial particle formation, and alone can explain 5-60% of α-pinene secondary organic aerosol mass yields measured at atmospherically relevant particle mass loadings. The responses of RO2, dimers, and highly oxygenated multifunctional compounds (HOM) to reacted α-pinene concentration and NO imply that an average ∼20% of primary α-pinene RO2 from OH reaction and 10% from ozonolysis autoxidize at 3-10 s-1 and ≥1 s-1, respectively, confirming both oxidation pathways produce HOM efficiently, even at higher NO concentrations typical of urban areas. Thus, gas-phase dimer formation and RO2 autoxidation are ubiquitous sources of low-volatility organic compounds capable of driving atmospheric particle formation and growth.
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