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Attia MS, Radwan MF, Ibrahim TS, Ibrahim TM. Development of Carvedilol-Loaded Albumin-Based Nanoparticles with Factorial Design to Optimize In Vitro and In Vivo Performance. Pharmaceutics 2023; 15:pharmaceutics15051425. [PMID: 37242667 DOI: 10.3390/pharmaceutics15051425] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/21/2023] [Accepted: 05/02/2023] [Indexed: 05/28/2023] Open
Abstract
Carvedilol, an anti-hypertensive medication commonly prescribed by healthcare providers, falls under the BCS class II category due to its low-solubility and high-permeability characteristics, resulting in limited dissolution and low absorption when taken orally. Herein, carvedilol was entrapped into bovine serum albumin (BSA)-based nanoparticles using the desolvation method to obtain a controlled release profile. Carvedilol-BSA nanoparticles were prepared and optimized using 32 factorial design. The nanoparticles were characterized for their particle size (Y1), entrapment efficiency (Y2), and time to release 50% of carvedilol (Y3). The optimized formulation was assessed for its in vitro and in vivo performance by solid-state, microscopical, and pharmacokinetic evaluations. The factorial design showed that an increment of BSA concentration demonstrated a significant positive effect on Y1 and Y2 responses with a negative effect on Y3 response. Meanwhile, the carvedilol percentage in BSA nanoparticles represented its obvious positive impact on both Y1 and Y3 responses, along with a negative impact on Y2 response. The optimized nanoformulation entailed BSA at a concentration of 0.5%, whereas the carvedilol percentage was 6%. The DSC thermograms indicated the amorphization of carvedilol inside the nanoparticles, which confirmed its entrapment into the BSA structure. The plasma concentrations of carvedilol released were observable from optimized nanoparticles up to 72 h subsequent to their injection into rats, revealing their longer in vivo circulation time compared to pure carvedilol suspension. This study offers new insight into the significance of BSA-based nanoparticles in sustaining the release of carvedilol and presents a potential value-added in the remediation of hypertension.
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Affiliation(s)
- Mohamed S Attia
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
| | - Mohamed F Radwan
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Tarek S Ibrahim
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Tarek M Ibrahim
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
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2
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Physicochemical Study of Albumin Nanoparticles with Chlorambucil. Processes (Basel) 2022. [DOI: 10.3390/pr10061170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Currently, nanotechnology is considered a promising strategy to enhance drug solubility and other physicochemical properties. Albumin is a biopolymer that can be used in drug delivery systems due to its biodegradability and biocompatibility. The aim of this study was to prepare and characterize albumin nanoparticles with chlorambucil as a controlled drug delivery system. Different concentrations of chlorambucil were incubated with bovine serum albumin (BSA) in order to prepare nanoparticles using the desolvation method. As a result, nanoparticles in sizes ranging from 199.6 to 382.6 nm exhibiting high encapsulation efficiency of chlorambucil were obtained. A spectroscopic study revealed concentration-dependent changes in secondary structure of the albumin chain and in the hydrophobicity of chlorambucil. Based on the results obtained, it was concluded that the investigated structures may be used in the development of a drug delivery system.
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3
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Sezigen S, Esim O, Sarper M, Savaser A. In vitro evaluation of two different types of obidoxime-loaded nanoparticles for cytotoxicity and blood-brain barrier transport. Toxicol Lett 2020; 330:53-58. [PMID: 32380126 DOI: 10.1016/j.toxlet.2020.03.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 03/16/2020] [Accepted: 03/23/2020] [Indexed: 10/24/2022]
Abstract
Nerve agents (NA) are chemical warfare munitions and their exposure causes a progressive inhibition of acetylcholinesterase (AChE). This inhibition causes NA-induced brain damage in central nervous system (CNS). Oximes reactivate AChE in both the peripheral nervous system and the CNS. Transport of the oxime across the blood-brain barrier (BBB) in the existed therapeutic concentrations at the brain parenchyma determines the effectiveness of antidote therapy on respiratory depression and NA-induced brain damage. However, oximes could not cross the BBB in therapeutic concentrations. The aim of this study was to load AChE reactivator obidoxime chloride to PLGA and PEG-b-PLGA nanoparticles and to improve the BBB transport of the molecule. Brain microvascular endothelial cells were used as the BBB model. 79.3 ± 4.2% of obidoxime was released from PLGA nanoparticles and 88.2 ± 4.4% of obidoxime was released from PEG-b-PLGA nanoparticles within 24 h. It was found that PEG-b-PLGA nanoparticles were ideal drug carrier because of its low tissue toxicity, few side effects, and controllable drug release profile. Transport efficiency of obidoxime across the BBB is a major challenge in the prevention of the CNS, the effectiveness of NA poisoning and new strategies like using obidoxime-loaded PEG-b-PLGA nanoparticles could overcome this challenge for the management of NA-induced brain damage.
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Affiliation(s)
- Sermet Sezigen
- University of Health Sciences, Department of Medical CBRN Defense, 06010, Ankara, Turkey.
| | - Ozgur Esim
- University of Health Sciences, Gulhane Faculty of Pharmacy, Department of Pharmaceutical Technology, 06010, Ankara, Turkey
| | - Meral Sarper
- University of Health Sciences, Gulhane Institute of Health Sciences, 06010, Ankara, Turkey
| | - Ayhan Savaser
- University of Health Sciences, Gulhane Faculty of Pharmacy, Department of Pharmaceutical Technology, 06010, Ankara, Turkey
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4
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Heuer-Jungemann A, Feliu N, Bakaimi I, Hamaly M, Alkilany A, Chakraborty I, Masood A, Casula MF, Kostopoulou A, Oh E, Susumu K, Stewart MH, Medintz IL, Stratakis E, Parak WJ, Kanaras AG. The Role of Ligands in the Chemical Synthesis and Applications of Inorganic Nanoparticles. Chem Rev 2019; 119:4819-4880. [PMID: 30920815 DOI: 10.1021/acs.chemrev.8b00733] [Citation(s) in RCA: 533] [Impact Index Per Article: 88.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The design of nanoparticles is critical for their efficient use in many applications ranging from biomedicine to sensing and energy. While shape and size are responsible for the properties of the inorganic nanoparticle core, the choice of ligands is of utmost importance for the colloidal stability and function of the nanoparticles. Moreover, the selection of ligands employed in nanoparticle synthesis can determine their final size and shape. Ligands added after nanoparticle synthesis infer both new properties as well as provide enhanced colloidal stability. In this article, we provide a comprehensive review on the role of the ligands with respect to the nanoparticle morphology, stability, and function. We analyze the interaction of nanoparticle surface and ligands with different chemical groups, the types of bonding, the final dispersibility of ligand-coated nanoparticles in complex media, their reactivity, and their performance in biomedicine, photodetectors, photovoltaic devices, light-emitting devices, sensors, memory devices, thermoelectric applications, and catalysis.
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Affiliation(s)
- Amelie Heuer-Jungemann
- School of Physics and Astronomy, Faculty of Engineering and Physical Sciences , University of Southampton , Southampton SO17 1BJ , U.K
| | - Neus Feliu
- Department of Laboratory Medicine (LABMED) , Karolinska Institutet , Stockholm 171 77 , Sweden.,Fachbereich Physik, CHyN , Universität Hamburg , 22607 Hamburg , Germany
| | - Ioanna Bakaimi
- School of Chemistry, Faculty of Engineering and Physical Sciences , University of Southampton , Southampton SO171BJ , U.K
| | - Majd Hamaly
- King Hussein Cancer Center , P. O. Box 1269, Al-Jubeiha, Amman 11941 , Jordan
| | - Alaaldin Alkilany
- Department of Pharmaceutics & Pharmaceutical Technology, School of Pharmacy , The University of Jordan , Amman 11942 , Jordan.,Fachbereich Physik, CHyN , Universität Hamburg , 22607 Hamburg , Germany
| | | | - Atif Masood
- Fachbereich Physik , Philipps Universität Marburg , 30357 Marburg , Germany
| | - Maria F Casula
- INSTM and Department of Chemical and Geological Sciences , University of Cagliari , 09042 Monserrato , Cagliari , Italy.,Department of Mechanical, Chemical and Materials Engineering , University of Cagliari , Via Marengo 2 , 09123 Cagliari , Italy
| | - Athanasia Kostopoulou
- Institute of Electronic Structure and Laser , Foundation for Research and Technology-Hellas , Heraklion , 71110 Crete , Greece
| | - Eunkeu Oh
- KeyW Corporation , Hanover , Maryland 21076 , United States.,Optical Sciences Division, Code 5600 , U.S. Naval Research Laboratory , Washington , D.C. 20375 , United States
| | - Kimihiro Susumu
- KeyW Corporation , Hanover , Maryland 21076 , United States.,Optical Sciences Division, Code 5600 , U.S. Naval Research Laboratory , Washington , D.C. 20375 , United States
| | - Michael H Stewart
- Optical Sciences Division, Code 5600 , U.S. Naval Research Laboratory , Washington , D.C. 20375 , United States
| | - Igor L Medintz
- Center for Bio/Molecular Science and Engineering, Code 6900 , U.S. Naval Research Laboratory , Washington , D.C. 20375 , United States
| | - Emmanuel Stratakis
- Institute of Electronic Structure and Laser , Foundation for Research and Technology-Hellas , Heraklion , 71110 Crete , Greece
| | - Wolfgang J Parak
- Fachbereich Physik, CHyN , Universität Hamburg , 22607 Hamburg , Germany
| | - Antonios G Kanaras
- School of Physics and Astronomy, Faculty of Engineering and Physical Sciences , University of Southampton , Southampton SO17 1BJ , U.K
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5
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Zyuzin MV, Yan Y, Hartmann R, Gause KT, Nazarenus M, Cui J, Caruso F, Parak WJ. Role of the Protein Corona Derived from Human Plasma in Cellular Interactions between Nanoporous Human Serum Albumin Particles and Endothelial Cells. Bioconjug Chem 2017. [PMID: 28644614 DOI: 10.1021/acs.bioconjchem.7b00231] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The presence of a protein corona on various synthetic nanomaterials has been shown to strongly influence how they interact with cells. However, it is unclear if the protein corona also exists on protein particles, and if so, its role in particle-cell interactions. In this study, pure human serum albumin (HSA) particles were fabricated via mesoporous silica particle templating. Our data reveal that various serum proteins adsorbed on the particles, when exposed to human blood plasma, forming a corona. In human umbilical vein endothelial cells (HUVECs), the corona was shown to decrease particle binding to the cell membrane, increase the residence time of particles in early endosomes, and reduce the amount of internalized particles within the first hours of exposure to particles. These findings reveal important information regarding the mechanisms used by vascular endothelial cells to internalize protein-based particulate materials exposed to blood plasma. The ability to control the cellular recognition of these organic particles is expected to aid the advancement of HSA-based materials for intravenous drug delivery.
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Affiliation(s)
- Mikhail V Zyuzin
- Fachbereich Physik, Philipps-Universität Marburg , 35037 Marburg, Germany
| | - Yan Yan
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne , Parkville, Victoria 3010, Australia.,Centre for BioNano Interactions, School of Chemistry, University College Dublin , Belfield, Dublin 4, Ireland
| | - Raimo Hartmann
- Fachbereich Physik, Philipps-Universität Marburg , 35037 Marburg, Germany
| | - Katelyn T Gause
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne , Parkville, Victoria 3010, Australia
| | - Moritz Nazarenus
- Fachbereich Physik, Philipps-Universität Marburg , 35037 Marburg, Germany
| | - Jiwei Cui
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne , Parkville, Victoria 3010, Australia.,Key Laboratory of Colloid and Interface Chemistry of Ministry of Education, and the School of Chemistry and Chemical Engineering, Shandong University , Jinan, Shandong 250100, China
| | - Frank Caruso
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne , Parkville, Victoria 3010, Australia
| | - Wolfgang J Parak
- Fachbereich Physik, Philipps-Universität Marburg , 35037 Marburg, Germany
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6
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Xu P, Wang R, Wang X, Ouyang J. Recent advancements in erythrocytes, platelets, and albumin as delivery systems. Onco Targets Ther 2016; 9:2873-84. [PMID: 27274282 PMCID: PMC4876107 DOI: 10.2147/ott.s104691] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In the past few years, nanomaterial-based drug delivery systems have been applied to enhance the efficacy of therapeutics and to alleviate negative effects through the controlled delivery of targeting and releasing agents. However, few drug carriers can achieve high targeting efficacy, even when targeting modalities and surface markers are introduced. Immunological problems have also limited their wide applications. Biological drug delivery systems, such as erythrocytes, platelets, and albumin, have been extensively investigated because of their unique properties. In this review, erythrocytes, platelets, and albumin are described as efficient drug delivery systems. Their properties, applications, advantages, and limitations in disease treatment are explained. This review confirms that these systems can be used to facilitate a specific, biocompatible, and smart drug delivery.
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Affiliation(s)
- Peipei Xu
- Department of Hematology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
| | - Ruju Wang
- Department of Hematology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China; Medical School, Southeast University, Nanjing, People's Republic of China
| | - Xiaohui Wang
- Department of Hematology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
| | - Jian Ouyang
- Department of Hematology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
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7
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Akbal Ö, Erdal E, Vural T, Kavaz D, Denkbaş EB. Comparison of protein- and polysaccharide-based nanoparticles for cancer therapy: synthesis, characterization, drug release, and interaction with a breast cancer cell line. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2016; 45:193-203. [DOI: 10.3109/21691401.2016.1170694] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Öznur Akbal
- Biology Department, Polatlı Art and Science Faculty, Gazi University, Ankara, Turkey
- Nanotechnology & Nanomedicine Division Hacettepe University, Ankara, Turkey
| | - Ebru Erdal
- Nanotechnology & Nanomedicine Division Hacettepe University, Ankara, Turkey
- Biology Department, Aksaray University, Aksaray, Turkey
| | - Tayfun Vural
- Chemistry Department, Biochemistry Division, Hacettepe University, Ankara, Turkey
| | - Doğa Kavaz
- Bioengineering Department, Cyprus International University, Haspolat, Nicosia, Northern Cyprus, Turkey
| | - Emir Baki Denkbaş
- Chemistry Department, Biochemistry Division, Hacettepe University, Ankara, Turkey
- Hacettepe University Advanced Technologies Application and Research Center, HUNITEK, Ankara, Turkey
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8
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Kalász H, Nurulain SM, Veress G, Antus S, Darvas F, Adeghate E, Adem A, Hashemi F, Tekes K. Mini review on blood-brain barrier penetration of pyridinium aldoximes. J Appl Toxicol 2014; 35:116-23. [PMID: 25291712 DOI: 10.1002/jat.3048] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/14/2014] [Accepted: 06/16/2014] [Indexed: 01/27/2023]
Abstract
This paper reviews the blood-brain barrier (BBB) penetration of newly developed pyridinium aldoximes. Pyridinium aldoximes are highly charged hydrophilic compounds used in the treatment of subjects exposed to organophosphonates because they are effective as acetylcholinesterase reactivators. Pyridinium aldoximes have antidotal effects against poisoning with cholinesterase inhibitors, a frequent problem affecting people working with organophosphate-based insecticides and pesticides. Toxic organophosphonate products such as sarin and tabun can be used by terrorists as chemical warfare agents. This poses a severe challenge to all innocent and peace-loving people worldwide. This review gives a brief summary of BBB transporters and description of the current in vitro and in vivo methods for the characterization of BBB penetration of established and novel pyridinium aldoximes. The authors provide a putative mechanism of penetration, outline some future ways of formulation and discuss the possible advantages and disadvantages of increasing BBB penetration.
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Affiliation(s)
- H Kalász
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089, Budapest, Nagyvárad tér 4, Hungary; Department of Pharmacology and Therapeutics, CMHS, United Arab Emirates University, Al Ain, P.O.Box 17666, United Arab Emirates
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9
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Peralta DV, He J, Wheeler DA, Zhang JZ, Tarr MA. Encapsulating gold nanomaterials into size-controlled human serum albumin nanoparticles for cancer therapy platforms. J Microencapsul 2014; 31:824-31. [DOI: 10.3109/02652048.2014.940012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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10
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Elzoghby AO, Samy WM, Elgindy NA. Albumin-based nanoparticles as potential controlled release drug delivery systems. J Control Release 2011; 157:168-82. [PMID: 21839127 DOI: 10.1016/j.jconrel.2011.07.031] [Citation(s) in RCA: 995] [Impact Index Per Article: 71.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 07/20/2011] [Indexed: 10/17/2022]
Abstract
Albumin, a versatile protein carrier for drug delivery, has been shown to be nontoxic, non-immunogenic, biocompatible and biodegradable. Therefore, it is ideal material to fabricate nanoparticles for drug delivery. Albumin nanoparticles have gained considerable attention owing to their high binding capacity of various drugs and being well tolerated without any serious side-effects. The current review embodies an in-depth discussion of albumin nanoparticles with respect to types, formulation aspects, major outcomes of in vitro and in vivo investigations as well as site-specific drug targeting using various ligands modifying the surface of albumin nanoparticles with special insights to the field of oncology. Specialized nanotechnological techniques like desolvation, emulsification, thermal gelation and recently nano-spray drying, nab-technology and self-assembly that have been investigated for fabrication of albumin nanoparticles, are also discussed. Nanocomplexes of albumin with other components in the area of drug delivery are also included in this review.
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Affiliation(s)
- Ahmed O Elzoghby
- Department of Industrial Pharmacy, Faculty of Pharmacy, Alexandria University, El-Khartoum Square, Azarita, Alexandria 21521, Egypt.
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11
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Wacker M, Zensi A, Kufleitner J, Ruff A, Schütz J, Stockburger T, Marstaller T, Vogel V. A toolbox for the upscaling of ethanolic human serum albumin (HSA) desolvation. Int J Pharm 2011; 414:225-32. [DOI: 10.1016/j.ijpharm.2011.04.046] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 04/08/2011] [Accepted: 04/16/2011] [Indexed: 10/18/2022]
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12
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Delmas D, Lin HY. Role of membrane dynamics processes and exogenous molecules in cellular resveratrol uptake: consequences in bioavailability and activities. Mol Nutr Food Res 2011; 55:1142-53. [PMID: 21648069 DOI: 10.1002/mnfr.201100065] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 03/16/2011] [Accepted: 03/25/2011] [Indexed: 12/16/2022]
Abstract
In the fields of nutrition prevention and therapy treatment, numerous studies have reported interesting properties of trans-resveratrol (RSV), a natural polyphenol against pathologies such as vascular diseases, cancers, viral infections and neurodegenerative processes. These beneficial effects are supported by more studies showing the pleiotropic actions of RSV. Nevertheless, a crucial question concerning these effects is how the polyphenol, when applied to an organism, gains access to its targets. In this review, we focus on the biochemical and biological parameters involved in RSV transport, particularly the role of the phospholipid bilayer in RSV uptake (passive diffusion, carrier-mediated transport) and of exogenous molecules modulating RSV transport and effects. The dynamic processes of the plasma membrane reveal the importance of the role of lipid composition in the fluidity, the lipid rafts in RSV endocytosis and the ATP-binding cassette transporters in RSV efflux. Specific membrane receptors such as integrin αvβ3 contribute to RSV uptake and to activate signalling pathways involved in apoptosis. We discuss the role of intracellular receptors (i.e. aryl-hydrocarbon and estrogen receptors). In addition, circulating molecules (i.e. albumin, haemoglobin, fatty acids, lipoproteins) play a role as RSV carriers. Finally, we developed a hypothesis concerning the relation between RSV uptake and its biological activities.
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Sit RK, Radić Z, Gerardi V, Zhang L, Garcia E, Katalinić M, Amitai G, Kovarik Z, Fokin VV, Sharpless KB, Taylor P. New structural scaffolds for centrally acting oxime reactivators of phosphylated cholinesterases. J Biol Chem 2011; 286:19422-30. [PMID: 21464125 DOI: 10.1074/jbc.m111.230656] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We describe here the synthesis and activity of a new series of oxime reactivators of cholinesterases (ChEs) that contain tertiary amine or imidazole protonatable functional groups. Equilibration between the neutral and protonated species at physiological pH enables the reactivators to cross the blood-brain barrier and distribute in the CNS aqueous space as dictated by interstitial and cellular pH values. Our structure-activity analysis of 134 novel compounds considers primarily imidazole aldoximes and N-substituted 2-hydroxyiminoacetamides. Reactivation capacities of novel oximes are rank ordered by their relative reactivation rate constants at 0.67 mm compared with 2-pyridinealdoxime methiodide for reactivation of four organophosphate (sarin, cyclosarin, VX, and paraoxon) conjugates of human acetylcholinesterase (hAChE). Rank order of the rates differs for reactivation of human butyrylcholinesterase (hBChE) conjugates. The 10 best reactivating oximes, predominantly hydroxyimino acetamide derivatives (for hAChE) and imidazole-containing aldoximes (for hBChE) also exhibited reasonable activity in the reactivation of tabun conjugates. Reactivation kinetics of the lead hydroxyimino acetamide reactivator of hAChE, when analyzed in terms of apparent affinity (1/K(ox)) and maximum reactivation rate (k(2)), is superior to the reference uncharged reactivators monoisonitrosoacetone and 2,3-butanedione monoxime and shows potential for further refinement. The disparate pH dependences for reactivation of ChE and the general base-catalyzed oximolysis of acetylthiocholine reveal that distinct reactivator ionization states are involved in the reactivation of ChE conjugates and in conferring nucleophilic reactivity of the oxime group.
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Affiliation(s)
- Rakesh K Sit
- Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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