Rapid isolation, reliable characterization, and water solubility improvement of polymethoxyflavones from cold-pressed mandarin essential oil

Comprehensive Chemical Characterization of Chia (Salvia hispanica L.) Seed Oil with a Focus on Minor Lipid Components

A comprehensive chemical characterization of different lipid components, namely fatty acid composition after derivatization in fatty acid methyl esters (FAMEs), triacylglycerols (TAGs), phospholipids (PLs), free fatty acids (FFAs), sterols, carotenoids, tocopherols, and polyphenols in Chia seed oil, obtained by Soxhlet extraction, was reported. Reversed phase liquid chromatography (RP-LC) coupled to UV and mass spectrometry (MS) detectors was employed for carotenoids, polyphenols, and TAGs determination; normal phase-LC in combination with fluorescence detector (FLD) was used for tocopherols analysis; PL and FFA fractions were investigated after a rapid solid phase extraction followed by RP-LC-MS and NanoLC coupled to electron ionization (EI) MS, respectively. Furthermore, gas chromatography (GC)-flame ionization (FID) and MS detectors were used for FAMEs and sterols analysis. Results demonstrated a significant content of bioactive compounds, such as the antioxidant tocopherols (22.88 µg mL^-1), and a very high content of essential fatty acids (81.39%), namely α-linolenic (62.16%) and linoleic (19.23%) acids. In addition, for the best of authors knowledge, FFA profile, as well as some carotenoid classes has been elucidated for the first time. The importance of free fatty acids in vegetable matrices is related to the fact that they can be readily involved in metabolic processes or biosynthetic pathways of the plant itself. For a fast and reliable determination of this chemical class, a very innovative and sensitive NanoLC-EI-MS analytical determination was applied.

Therapeutic effectiveness of sinensetin against cancer and other human complications: A review of biological potential and pharmacological activities

BACKGROUND

Plant and their active phytoproducts have been used in modern medicine and playing an important role in the health sectors since a very early age. Human beings need a considerable amount of these plant-based phytochemicals for their health. The flavonoidal class phytochemical is an important class of natural products in modern healthcare because of their different pharmacological activities and health benefits. Flavonoidal class phytochemicals have been used to treat diabetes and related secondary complications in humans. Flavonoids have anti-apoptotic, anti-hyperlipidemic, anti-inflammatory, and anti-oxidant potential in the health sectors. Sinensetin, also called 3',4',5,6,7-pentametoksiflavon is a colorless compound with a molecular weight 372.37g/mol and is found to be present in the Orthosiphon stamineus.

METHODS

In the present investigation, we aim to collect scientific information on sinensetin and analyze it for its biological potential and therapeutic benefits against various types of disorders and complications. Medicinal importance and pharmacological activities data have been collected and analyzed in the present work for sinensetin through literature data analysis of different research works. Google Science Direct, PubMed, Scopus, and Google Scholar were mainly searched to collect the scientific information in the present work. The present work analyzed sinensetin's biological potential, pharmacological activities, and analytical aspects.

RESULTS

Literature data analysis of different scientific research works revealed the biological potential of phytochemicals in medicine, including flavonoids. Sinensetin has anti-tumor, anti-inflammatory, anti-oxidant, anti-diabetic, and antibacterial activities through their testing in different in vitro and in vivo models. Sinensetin has physiological functions, including anti-oxidant, anti-inflammation, and anti-cancer potential in medicine. Scientific data analysis signified the biological importance of sinensetin against tumors, gastric cancer, colorectal cancer, breast cancer, diabetes, influenza H1N1 infection, obesity, inflammation, colitis, brain disorders, and microbial infections. Further biological potential of sinensetin on enzymes and angiogenesis has been analyzed in the present work. Sinensetin was isolated through different analytical and extraction techniques, including chromatographic techniques.

CONCLUSION

Literature data analysis signified sinensetin's biological potential and pharmacological activities in medicine.

The history of electron ionization in LC-MS, from the early days to modern technologies: A review

This review article traces the history of the use of liquid chromatography coupled with mass spectrometry (LC-MS) using electron ionization (EI) from the first attempts up to the present day. At the time of the first efforts to couple LC to MS, 70 eV EI was the most common ionization technique, typically used in gas chromatography-mass spectrometry (GC-MS) and providing highly reproducible mass spectra that could be collated in libraries. Therefore, it was obvious to transport this dominant approach to the early LC-MS coupling attempts. The use of LC coupled to EI-MS is challenging mainly due to restrictions related to high-vacuum and high-temperature conditions required for the operation of EI and the need to remove the eluent carrying the analyte before entering the ion source. The authors will take readers through a journey of about 50 years, showing how through the succession of different attempts it has been possible to successfully couple LC with EI-MS, which in principle appear to be incompatible.

Dietary Intake of Coumarins and Furocoumarins through Citrus Beverages: A Detailed Estimation by a HPLC-MS/MS Method Combined with the Linear Retention Index System

Official regulations concerning the maximum number of substances in food are introduced as a consequence of possible adverse effects, after oral administration. In this regard, analytical methods are necessary in order to determine specific targets. Among oxygen heterocyclic compounds (OHCs, that are furocoumarins, coumarins and polymethoxyflavones), only coumarin is subject to restriction by the Regulation (EC) No 1334/2008 of the European Parliament. Furocoumarins are known for their phototoxicity and other side effects due to their dietary intake; however, an official limit about the maximum content of these compounds in food is still missing. The lack of information about the real amount of these compounds in food is responsible for the conflicting opinions about the introduction of an official limit. The HPLC-MS/MS method here proposed, in combination with the linear retention index system, represents an innovative analytical strategy for the characterization of OHCs in citrus beverages. Several types of drinks were analysed in order to quantify 35 OHCs in total. This method is suitable for the quality control of OHCs in food and the obtained results may be considered as informative data useful for the regulatory authorities in the emission of new opinions and for a potential new regulation in this field.

Linear retention index approach applied to liquid chromatography coupled to triple quadrupole mass spectrometry to determine oxygen heterocyclic compounds at trace level in finished cosmetics

In the European Union, cosmetic products are regulated by the Cosmetics Regulation (EC) No. 1223/2009. The Analytical Working Group of the International Fragrance Association (IFRA) suggested that a new sensitive analytical method is needed to determine psoralens in finished cosmetic products. This research provides an HPLC-MS/MS method for the quality control of 20 furocoumarins, 8 coumarins and 7 polymethoxyflavones in cosmetics. Thanks to the high sensitivity of the tandem mass spectrometry detection in Multiple Reaction Monitoring mode, psoralens contained in trace have been quantified in different products. The Limits of Quantifications were in the range 0.3-74 μg L^-1. A reliable identification was achieved combining the Linear Retention Index (LRI) system with the MS and MS/MS libraries. In particular, the attribution was based on the spectra similarity filtered by the LRI parameter. The robustness and reproducibility of the LRI approach was demonstrated by the comparison of the HPLC-MS/MS results here reported with those obtained in our previous study, by using an HPLC-PDA system. This method could be taken into account for quality control of furocoumarins in cosmetics, and by the main associations, such as IFRA, for the purpose of issuing new opinions.

Nanoencapsulation of Plant Volatile Organic Compounds to Improve Their Biological Activities

Plant volatile organic compounds (volatiles) are secondary plant metabolites that play crucial roles in the reproduction, defence, and interactions with other vegetation. They have been shown to exhibit a broad range of biological properties and have been investigated for antimicrobial and anticancer activities. In addition, they are thought be more environmentally friendly than many other synthetic chemicals 1. Despite these facts, their applications in the medical, food, and agricultural fields are considerably restricted due to their volatilities, instabilities, and aqueous insolubilities. Nanoparticle encapsulation of plant volatile organic compounds is regarded as one of the best strategies that could lead to the enhancement of the bioavailability and biological activity of the volatile compounds by overcoming their physical limitations and promoting their controlled release and cellular absorption. In this review, we will discuss the biosynthesis and analysis of plant volatile organic compounds, their biological activities, and limitations. Furthermore, different types of nanoparticle platforms used to encapsulate the volatiles and the biological efficacies of nanoencapsulated volatile organic compounds will be covered.

The influence of injection volume on efficiency of microbore liquid chromatography columns for gradient and isocratic elution

The injection volume and the associated column volume overload is one of the most common issues in miniaturized chromatography. The injection volume should not exceed 10% of the effective column volume. A further reduction of the injection volume leads to an increase in chromatographic efficiency. However, the signal intensity must be above a certain threshold to generate a chromatographic peak that can be detected. Therefore, the injection volume has to be optimized to reach the ideal balance between chromatographic efficiency and sensitivity. This study examined the general influence of the injection volume for both isocratic and gradient elution, depending on the retention factor and peak standard deviation. For this purpose, substances of different polarity were selected to represent a broad elution spectrum. Besides the model analyte naphthalene, these were mainly pharmaceuticals. For all measurements a microbore column with an ID of 300 µm and packed with 1.9 μm fully porous particles was used. For isocratic elution, the injection volume was varied between 4 and 16% of the effective column volume. The retention factors were adjusted between 2 and 10. For gradient elution, the injection volume was varied between 4 and 160% of the effective column volume. The observed effects were further investigated using the gradient kinetic plot theory. In isocratic elution, a loss in plate height up to 50% was observed for components that elute near the void time. A significant reduction of the chromatographic efficiency was noticed up to a retention factor of 4. In gradient elution, a reduction in peak capacity could only be observed if the injection volume exceeded 40% of the effective column volume. For some substances, only a slight loss in peak capacity was noticed even with a volume overload of 160%.

The retention index approach in liquid chromatography: An historical review and recent advances

Historically, retention parameters were reliably used as identification criterion in chromatographic analytical systems. However, pure analytical standards are necessary to determine the retention behaviour of a given compound. In recent decades, mass spectrometer (MS) became the detector of choice to obtain structural information on unknown peaks, thanks to the elucidation of fragments, often arisen from the loss of specific functional groups. The cost and the level of experience of the operators is surely higher compared to the use of retention data. Therefore, the aim of the present review is to describe the efforts in the introduction of the Linear Retention Index (LRI) in routine, interlaboratory applicable identification procedures. The requirements and the main challenges will be discussed, even compared to gas chromatography methods, in which LRI is stably used for identification purposes, usually in combination with MS spectral libraries. The higher number of LC-amenable molecules and the wide range of LC mobile phase compositions make the building of universal LRI database a very challenging task. The limitations encountered in the past decades are reported, together with new proposals in order to overcome such issues.

Analysis of impurities in pharmaceuticals by LC-MS with cold electron ionization

Pharmaceuticals require careful and precise determination of their impurities that might harm the user upon consumption. Although today, the most common technique for impurities identification is liquid chromatography-mass spectrometry (LC-MS/MS), it has several downsides due to the nature of the ionization method. Also, the analyses in many cases are targeted thus despite being present, some of the compounds will not be revealed. In this paper, we propose and show a new method for untargeted analysis and identification of impurities in active pharmaceutical ingredients (APIs). The instrument used for these analyses is a novel electron ionization (EI) LC-MS with supersonic molecular beams (SMB). The EI-LC-MS-SMB was implemented for analyses of several drug samples spiked with an impurity. The instrument provides EI mass spectra with enhanced molecular ions, named Cold EI, which increases the identification probabilities when the compound is identified with the aid of an EI library like National Institute of Standards and Technology (NIST). We analyzed ibuprofen and its impurities, and both the API and the expected impurity were identified with names and structures by the NIST library. Moreover, other unexpected impurities were found and identified proving the ability of the EI-LC-MS-SMB system for truly untargeted analysis. The results show a broad dynamic range of four orders of magnitude at the same run with a signal-to-noise ratio of over 10 000 for the API and almost uniform response.

Electron Ionization Mass Spectrometry for Both Liquid and Gas Chromatography in One System without the Need for Hardware Adjustments

A new instrument that bridges the gap between gas chromatography (GC) and liquid chromatography (LC) mass spectrometry (MS) was developed. In this instrument GC-MS and electron ionization LC-MS were combined in one MS system with method based mode changing. The LC pneumatic spray formation interface to MS was mounted on top of an otherwise unused GC detector slot and was connected with a flow restriction capillary to the MS through the GC oven and into the MS transfer line, parallel to the GC capillary column. The LC output mobile phase flow is directed into a spray formation and vaporization chamber. The pneumatic spray results in fine spray droplets that are thermally vaporized at a pressure equal to or greater than ambient. A portion of the vaporized mixture is directed into the heated flow restriction capillary that connects the spray formation and vaporization chamber into the electron ionization (EI) ion source, while most of the vaporized spray is released to the atmosphere. The combined GC-MS and LC-MS system can work either with standard EI or with cold EI via interfacing the flow restriction capillary into a supersonic nozzle forming a supersonic molecular beam of a vibrationally cold sample compound. We found that EI-LC-MS with cold EI has many benefits when compared with standard EI. The EI-LC-MS interface can also serve for flow injection analysis. The performance of the combined system is demonstrated in the analysis of a few sample mixtures by both GC-MS and LC-MS analysis, sequentially without hardware adjustments.

Combining linear retention index and electron ionization mass spectrometry for a reliable identification in nano liquid chromatography

The present research is focused on the object to improve identification capability in liquid chromatography (LC), by creating a system as similar as possible to gas chromatography (GC), where the combination/complementarity of Linear Retention Index (LRI) and Electron Ionization Mass Spectrometry (EI-MS) data makes the identification process easy, automatic and reliable. Conversely, in LC the untargeted characterization of real-world samples is still a challenge, due to the not repeatable and poorly informative nature of typical atmospheric pressure ionization mass spectrometry, normally hyphenated to LC. In the last decades the miniaturization of LC instrumentation together with the considerable progresses in MS vacuum pump capability has made the LC-EI-MS hyphenation more feasible. In the present work, a prototypal nanoLC-EI-MS system was used for the determination of typically LC-amenable compunds, such as coumarins, furocoumarins and polymethoxyflavones in citrus essential oils. All the compounds provided high quality EI-MS spectra, evaluated by the comparison with thousands of spectra present in commercial EI-MS libraries. Spectral similarities major than 80% were achieved. Furthermore, an LRI system, based on the use of an alkyl aryl ketone homologue reference series, was proposed as additional filter to achieve a univocal identification. Then, a novel dual-filter LRI/EI-MS library was built and resulted very helpful in the case of isomeric compounds characterized by identical EI-MS spectrum, but different retention behaviour. The very low inter-day variability attained for each LRI value, together with the satisfactory chromatographic resolution of the developed method, led to a 100% reliability of the identification process based on LRI.

Free fatty acid profiling of marine sentinels by nanoLC-EI-MS for the assessment of environmental pollution effects

The present work aims to elucidate the free fatty acid (FFA) profile of the mussel Mytilus galloprovincialis caged in an anthropogenically impacted area and in a reference site through an innovative and validated analytical approach for the assessment of biological alterations induced by marine pollution. The FFA pattern is involved in the regulation of different cellular pathways and differs with respect to metabolic stimuli. To this purpose, the lipid fraction of mussels coming from both sampling areas was extracted and the FFA fractions were isolated and purified by a solid phase extraction; then, nano-scale liquid chromatography coupled to electron ionization mass spectrometry (nanoLC-EI-MS) was employed for the characterization of the two samples. A total of 19 and 17 FFAs were reliably identified in the mussels coming from the reference and polluted site, respectively. Significant qualitative and quantitative differences found in saturated, monounsaturated and polyunsaturated species may be exploited as typical pollution biomarkers (e.g. alteration of the fatty acid biosynthetic system and lipotoxicity) and explain adverse and compromising effects (e.g. oxidative stress and inflammatory processes) related to environmental pollution.