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The isolation of a compound from a natural source involves many organic and mostly toxic solvents for extraction and purification. Natural deep eutectic solvents have been shown to be efficient options for the extraction of natural products. They have the advantage of being composed of abundantly available common primary metabolites, being nontoxic and environmentally safe solvents. The aim of this study was to develop a natural deep eutectic solvent-based extraction method for galanthamine, an important therapeutic agent for the treatment of Alzheimerʼs disease. This alkaloid can be produced by synthesis or by extraction from Narcissus bulbs. To develop an efficient extraction method, a number of different natural deep eutectic solvents was first tested for their solubilization capacity of galanthamine bromide salt. Promising results were obtained for ionic liquids, as well as some amphoteric and acidic natural deep eutectic solvents. In a two-cycle extraction process, the best solvents were tested for the extraction of galanthamine from bulbs. The ionic liquids produced poor yields, and the best results were obtained with some acid and sugar mixtures, among which malic acid-sucrose-water (1 : 1 : 5) proved to be the best, showing similar yields to that of the exhaustive Soxhlet extraction with methanol. Furthermore, the natural deep eutectic solvent was more selective for galanthamine.

Natural products have been the most important source for drug development throughout the human history. Over time, the formulation of drugs has evolved from crude drugs to refined chemicals. In modern drug discovery, conventional natural products lead-finding usually uses a top-down approach, namely bio-guided fractionation. In this approach, the crude extracts are separated by chromatography and resulting fractions are tested for activity. Subsequently, active fractions are further refined until a single active compound is obtained. However, this is a painstakingly slow and expensive process. Among the alternatives that have been developed to improve this situation, metabolomics has proved to yield interesting results having been applied successfully to drug discovery in the last two decades. The metabolomics-based approach in lead-finding comprises two steps: (1) in-depth chemical profiling of target samples, e.g. plant extracts, and bioactivity assessment, (2) correlation of the chemical and biological data by chemometrics. In the first step of this approach, the target samples are chemically profiled in an untargeted manner to detect as many compounds as possible. So far, NMR spectroscopy, LC-MS, GC-MS, and MS/MS spectrometry are the most common profiling tools. The profile data are correlated with the biological activity with the help of various chemometric methods such as multivariate data analysis. This in-silico analysis has a high potential to replace or complement conventional on-silica bioassay-guided fractionation as it will greatly reduce the number of bioassays, and thus time and costs. Moreover, it may reveal synergistic mechanisms, when present, something for which the classical top-down approach is clearly not suited. This chapter aims to give an overview of successful approaches based on the application of chemical profiling with chemometrics in natural products drug discovery.

According to textual research of books from ancient times till now, there are three main preparation methods of "fried licorice", including frying licorice without excipients (F), frying licorice after dipping with water (W), and frying licorice with honey (H). However, with the development over many successive generations, honey frying has gradually become the main processing form of licorice, whereas the fried licorice is nowadays rarely used.The objectives of this study were to clarify the differences of the three forms of "fried licorice" in chemical composition and pharmacological activities, and to screen quality markers for differently processed licorice. It is expected to provide a scientific basis for the rational choice of "fried licorice" as medicine.Non-target metabolomic analysis based on UHPLC-QE-Orbitrap-MS was conducted to compare the chemical differences between the differently processed licorice material. Pharmacodynamically, the differences in immunomodulatory activity (including intestinal flora experiment), anti-inflammatory activity, and hepatoprotective activity of the differently processed licorice were evaluated. Furthermore, multivariate statistical analysis was performed to screen potential quality markers of honey-fried licorice. The serum concentration of selected markers was determined by UHPLC-QqQ-MS.Metabolomic analysis showed no difference in the chemical composition of F and W, whereas the chemical composition of H was significantly different from that of F and R. The immunomodulatory activity, anti-acute inflammatory effect, and hepatoprotective effect of licorice were significantly improved after frying with honey; No significant differences were observed between F and H in term of immunomodulatory activity and anti-acute inflammatory effect, whereas, H is better than F in terms of liver-protective activity. The intestinal flora experiment confirmed that H does have immunomodulatory activity, while F may induce an increased abundance of certain pathogenic bacteria in the intestine. Multivariate statistical analysis suggests that the content of liquiritin (2), liquiritigenin (3), isoliquiritin (5), isoliquiritigenin (6) and glycyrrhizic acid (7) plusing glycyrrhetinic acid (8) in H group is closely correlated with its improved effects.This study provides a scientific rational for the selection of "fried licorice" processing methods. In addition, it provides a scientific basis for the selection of quality markers of differently processed licorice.

Based on the hypothesis that the variation of the metabolomes of latex is a response to selective pressure and should thus be affected differently from other organs, their variation could provide an insight into the defensive chemical selection of plants. Metabolic profiling was used to compare tissues of three Euphorbia species collected in diverse regions. The metabolic variation of latexes was much more limited than that of other organs. In all the species, the levels of polyisoprenes and terpenes were found to be much higher in latexes than in leaves and roots of the corresponding plants. Polyisoprenes were observed to physically delay the contact of pathogens with plant tissues and their growth. A secondary barrier composed of terpenes in latex and in particular, 24-methylenecycloartanol, exhibited antifungal activity. These results added to the well-known role of enzymes also present in latexes, show that these are part of a cooperative defense system comprising biochemical and physical elements. Supplementary Information The online version contains supplementary material available at 10.1007/s10886-021-01274-x.

Metabolomics of human biological fluids or tissues is used to discover markers for diseases by comparing the metabolome of the patients against healthy individuals. Ultimately, these markers can be used in drug discovery to determine how medications normalize (at least in part) the human metabolome at specific disease stages to homeostatic. Likewise, the health effects of food can be studied. Even metabolomics of the food can be combined with metabolomics of the treated patients to correlate compounds from food with measurable health effects from clinical studies. Various chemometric analyses of these metabolomics data are used to identify markers for diseases and to obtain evidence for health effects. This review discusses recent researches (published from 2013 to 2021) on whether specific dietary intervention to humans suffering from metabolic disorders may improve their pathological status. The scope is limited to those associated with major lifestyle diseases such as diabetes, obesity, and cardiovascular diseases, for which food is thought may have detrimental as well as beneficial effects on human health. It includes metabolites characterization of different biological samples such as the human serum/plasma, urine, saliva, feces, or ileal fluid. Whether the study results supported the claimed health benefits and whether the research was conducted with appropriate study design, was criticized.

Galanthamine is a competitive acetylcholinesterase (AChE) inhibitor naturally produced by the plants of Amaryllidaceae family. It is used as a treatment against Alzheimer's disease (AD) and is an FDA approved drug. The content of this metabolite varies between different plant species as well as within the same species. To measure the galanthamine levels diverse extraction and pre-analytical methods at laboratory scale have been developed for chromatographic and spectroscopic analysis. Galanthamine identification and quantification methods are changing over time due to improvements in equipment. Development of new technologies also leads to new methods. At lab scale, there are various methods which can be used for the extraction of galanthamine from different sources. The final identification and quantitation of the alkaloid(s) can be achieved with different methods such as thin layer chromatography (TLC), liquid chromatography (HPLC, UPLC, LC-MS), GC(-MS) and nuclear magnetic resonance (NMR) spectroscopy. All these methods have been reviewed in this chapter. From different studies, it is evident that extraction time and method robustness are the basic parameters for selecting the best method. TLC, HPLC and GC-FID can be used for quick identification and quantitation, but for proper analysis standard reference compounds are required. Moreover, pre-analytical sample preparation is time consuming for LC-MS and particularly GC–MS. Considering these aspects 1HNMR spectroscopy is the fastest and best reproducible method, because compounds are identified and quantified based on their highly specific signals in the spectra of the extracts. For large scale extraction various methods (solvent extraction, microwave-assisted extraction, and supercritical carbon dioxide extraction) have been developed for galanthamine extraction and purification. But mostly classical organic solvent extraction is used in industrial production due to low cost and availability of large-scale extraction facilities. Galanthamine recovery rate is relatively low in this method. Recently, progress have been made towards developing better methods. Among these developments, super critical fluid (carbon dioxide) extraction has great interest because it is a more environmentally friendly (green) technology. Although the solvent extraction methods are commercially applied to date, there is still a possibility for improvement in the extraction and purification process of galanthamine from plants as based on the present yields, still only about 50% of galanthamine present is obtained from the plant material in the large-scale extraction process.

Narcissus is mostly grown for horticultural/decorative purposes in the fields and home gardens. Previously, galanthamine isolation (from the bulbs to produce medicine for the treatment of Alzheimer's disease) has been established as a novel use. Moreover, recent studies have also shown that Narcissus bulbs are also a source of several other interesting biologically active compounds and particularly some alkaloids. Various metabolites are produced at different time points during the growth cycle of plants. Also, for Narcissus bulbs it is important to find from an economical point of view the optimum time point for harvesting in its growth cycle, as the levels of galanthamine might be correlated with the age of the Narcissus bulbs. The aim of this study was to investigate the differences in the metabolites and specifically in the alkaloid contents based on a 1, 2- or 3-years harvesting cycle of Narcissus bulbs. Moreover, the effect of the cultivation site was studied for Narcissus pseudonarcissus cv Carlton which is well known for galanthamine production. Different methods were used for the analysis of these alkaloids. Untargeted NMR based metabolomics was used for overall metabolic changes and galanthamine quantitation. Whereas targeted GC-FID and GC–MS were used respectively for quantitative and qualitative analysis of major and minor alkaloids. An alkaloid specific acid-base extraction method was used in the GC–MS and GC–FID analysis. The results show that the contents of the metabolites vary significantly with the age of the bulbs. The contents of galanthamine were highest in two years old bulbs. It was also found that the alkaloid contents from the same variety grown at different locations differ from each other. Results presented here clearly indicate that] age of the bulb are important factors to consider for the industrial production of certain alkaloids from the plants as yields of alkaloids may vary, certain conditions may lead to an increase of the yield with 10–15%.

Honey-processed licorice has been used since ancient times. It was recorded that honey-processing has the effect of improving the immunomodulatory efficacy of licorice, which has been confirmed by modern pharmacological studies. However, it is still unknown why honey-processing can enhance the immunomodulatory activity of licorice. Our previous research demonstrated that honey has natural deep eutectic solvent (NADES) characteristics. In this study, we investigated the synergistic effect of honey on licorice to elucidate the possible potentiation of honey-frying on licorice.Immunological experiments were conducted to investigate whether the honey-processing could enhance the immunomodulatory efficacy of licorice in vivo. Then, the synergistic mechanism of honey and licorice was explored based on cell bioactivity tests, metabolomics analysis, bioavailability test, and Fourier transform-infrared (FT-IR) spectra.Pharmacological experiment verified that honey-processing enhanced the immunomodulatory efficacy of licorice. Moreover, honey increased the total flavonoid and polysaccharide contents in licorice decoction, improved the thermal stability and oral bioavailability of certain pharmacologically active constituents, and augmented their overall immunostimulatory functions. Similar effects of honey were also observed with a honey analogue GFSH, a NADES made of glucose, fructose, and sucrose with certain amount of water. The above effects might be due to multiple molecular interactions between active compounds and sugar molecules of honey.These findings indicate that the biological activities of medicinal plants might be fortified by honey due to the synergism between licorice and honey. At the meantime, these findings provide theoretical and empirical basis for potential novel applications of honey or other NADESs at augmenting the health-promoting effects of medicinal plants.

Background Honey has been widely used in medicine plants processing since ancient times. Honey-frying of herbal medicine is a well-known treatment in Chinese medicine. It has been reported that honey-frying can improve the immunomodulatory efficacy of licorice. However, it is still unknown why honey-frying improves the immunomodulatory activity of licorice. And our previous research demonstrated that honey has natural deep eutectic solvent (NADES) characteristics. NADES is a kind of solvent with broad polarity range and has attracted extensive attention of scholars in different fields. In the present study, we investigated chemical basis underline the possible potentiation of honey-frying on licorice to elucidate its chemical mechanism. Methods Firstly, immunological experiments were conducted to investigate whether the honey-processing could enhance the immunomodulatory efficacy of licorice. Then, the synergistic mechanism of honey-processed licorice was explored based on cell biological activity test, chemical composition test, bioavailability test, and Fourier transform-infrared (FT-IR) spectra. Results Pharmacological experiment verified that honey-processing enhanced the immunomodulatory efficacy of licorice. Moreover, honey increased the total flavonoid and polysaccharide contents in licorice decoction, improved the thermal stability and oral bioavailability of certain pharmacologically active constituents, and augmented their overall immunostimulatory functions. Similar effects of honey were also observed with NADES. The above effects are due to multiple molecular interactions between active compounds and sugar molecules of NADES. Conclusion These findings indicate that the biological activities of medicinal plants might be fortified by NADES/honey in the processing of the plant material. At the meantime, these findings provide theoretical and empirical basis for potential novel applications of honey or other NADESs at augmenting the health-promoting effects of medicinal plants.

Ethnopharmacological relevance The quality control of Traditional Chinese medicine (TCM) is a scientific problem and an industrial issue, which hampers the development of evidence based TCM. The concept of quality markers (Q-markers) is proposed and has been applied to the quality evaluation of TCM based on its clinical efficacy. However, more specific methods are needed to put this idea into practice. The standard decoction is a representative of decoction used in clinical practice and it can be used for the discovery of Q-markers related to the clinical efficacy of TCM. Aim of the study In this study, a systemic strategy was established to discover Q-markers related to the clinical efficacy of TCM Ephedrae Herba (EH), dried stem of Ephedra sinica Stapf. The different processed materials of EH have different clinical applications, though originating from the same medicinal herb. Materials and methods The standard decoction of each of the processed materials was prepared and a 1HNMR metabolomics approach and total polysaccharide analysis were used to identify potential Q-markers related to the different clinical applications of EH. Correlation analysis was made of the measured biological activity and the holistic chemical profile. Results The results showed that total polysaccharides and alkaloids were Q-markers for EH preparations. Conclusion This study demonstrates that the standard decoction is a reasonable research objective to explore chemical markers that correlate with the clinical efficacy of TCM.

Green technology is moving from an option to a must in modern industrial processing. Solvents are the core of the food, pharmaceutical, cosmetic, agrochemical, chemical, and biotechnological process technologies. In the past two decades, supercritical fluids, ionic liquids, and deep eutectic solvents became the most actively investigated as potential green solvents, especially in the field associated with food, flavors, fragrances, and medicinal plants processing. This review assesses recent information about the novel solvent technologies.

The use of natural deep eutectic solvents (NADES) as multifunctional solvents for limonene bioprocessing was reported. NADES were used for the extraction of limonene from orange peel wastes, as solvent for the chemoenzymatic epoxidation of limonene, and as sacrificial electron donor for the in situ generation of H2O2 to promote the epoxidation reaction. The proof‐of‐concept for this multifunctional use was provided, and the scope and current limitations of the concept were outlined.

International audience; With contributions from the global natural product (NP) research community, and continuing the Raw Data Initiative, this review collects a comprehensive demonstration of the immense scientific value of disseminating raw nuclear magnetic resonance (NMR) data, independently of, and in parallel with, classical publishing outlets. A comprehensive compilation of historic to present-day cases as well as contemporary and future applications show that addressing the urgent need for a repository of publicly accessible raw NMR data has the potential to transform natural products (NPs) and associated fields of chemical and biomedical research. The call for advancing open sharing mechanisms for raw data is intended to enhance the transparency of experimental protocols, augment the reproducibility of reported outcomes, including biological studies, become a regular component of responsible research, and thereby enrich the integrity of NP research and related fields.

Some medicines are poorly soluble in water. For tube feeding and parenteral administration, liquid formulations are required. The discovery of natural deep eutectic solvents (NADES) opened the way to potential applications for liquid drug formulations. NADES consists of a mixture of two or more simple natural products such as sugars, amino acids, organic acids, choline/betaine, and poly-alcohols in certain molar ratios. A series of NADES with a water content of 0–30% (w/w) was screened for the ability to solubilize (in a stable way) some poorly water-soluble pharmaceuticals at a concentration of 5 mg/mL. The results showed that NADES selectively dissolved the tested drugs. Some mixtures of choline-based NADES, acid-neutral or sugars-based NADES could dissolve chloral hydrate (dissociated in water), ranitidine·HCl (polymorphism), and methylphenidate (water insoluble), at a concentration of up to 250 mg/mL, the highest concentration tested. Whereas a mixture of lactic-acid–propyleneglycol could dissolve spironolacton and trimethoprim at a concentration up to 50 and 100 mg/mL, respectively. The results showed that NADES are promising solvents for formulation of poorly water-soluble medicines for the development of parenteral and tube feeding administration of non-water-soluble medicines. The chemical stability and bioavailability of these drug in NADES needs further studies.

Many plants produce exudates as defense mechanism to hamper pests and pathogens. Plant exudates include latexes, resins, gums, root exudates, and also biofluids produced by carnivorous plants. Plants exudates consist of, among others, polysaccharides, lipids, proteins, organic acids and bases, sugars, and amino acids. All these small molecules are NADES components. In this chapter, the chemical compositions of plant exudates, especially leaf exudates, and Drosera plant biofluids will be elaborated. Metabolic profiling approaches based on 1H NMR and GC–MS were performed on the biofluids of the Drosera species. The 1H NMR spectra showed a high level of myo-inositol and sugars in the biofluids as well as some organic acids. To further confirm the identity of the sugars and to identify some minor components, GC–MS was employed. This gave similar results as the 1H NMR spectroscopy. All the tested exudates were found to contain sugars, such as fructose, glucose, arabinose, sucrose, and xylose; organic acids, such as glucuronic acid and ascorbic acid; and myo-inositol. Those Drosera ingredients are known to be strong hydrogen-bond donors. Based on the information obtained from the 1H NMR and GC–MS results, new NADESs compositions were proposed and they were tested in vitro, of which indeed five combinations formed liquids. However, considering that these Drosera biofluids consist mainly of water and other materials, it may indicate that the stable high viscosity droplets typical for the Drosera species must be due in part to other physical-chemical forces, such as gel formation by polysaccharides with calcium ions. A possible role of the NADES-like liquids could be in stabilizing proteins, or the formation of biofilms enabling a faster digesting of the prey. The myo-inositol that was clearly a major compound in the exudate might be involved in protecting the leaves and the sugar containing exudate from herbivory. The occurrence of some common products found in fermentation processes might indicate that microorganisms are present in the biofluid.

Plants have been used as sources of food, beverages, fibers, or building materials, and also as sources of poisons, drugs, colorants, flavors, fragrances, and insecticides. Many natural products are now produced as specialty chemicals for applications in the food, pharmaceutical, and flavor and fragrance industries. Synthesis is usually directed at certain compounds, which will only lead to improved drugs for already known receptors, whereas natural compounds are much more probable to show totally new modes of action in broad screens. The screening methods for antibiotic and antiviral activities are rather straightforward. The use of isolated organs for studying certain biological activities is decreasing because of the wish to reduce the number of animal experiments. In plants, a large number of compounds is present, encompassing a broad spectrum of polarities. Screening of plant cell cultures for new biologically active compounds is feasible.

A commission was established to stimulate research in this field. The first action was an inventory of research at the Dutch universities essential for biotechnology. Several groups already studied plant secondary metabolite production in cell cultures, others directed their research into this field. In 1982 about 40 researchers were active in this field. In 1986 this had increased to almost 100 researchers. The choice of the subjects was determined by the expertise within the participating groups and the potential areas of application. The lignans, derived from the phenylpropanoid pathway, have interest as antitumor compounds, and the Plant Molecular Biology group in Amsterdam had expertise in this pathway; the pharmacognosy department in Groningen was interested in antitumor compounds. Screening for high productivity can be done on several levels. High-producing plants, calli, or cell clones obtained from single cells or protoplasts have been used for screening of high- producing strains.

Due to the complex nature of traditional medicines, quality control methods need to cover two aspects: compliance of raw materials with quality standards and process control. Astragali radix (AR), the roots of Astragalus mongholicus Bunge, was selected in this study as an example of a widely used traditional medicine in various formulations. Astragaloside IV (AG IV) and calycosin 7-O-β-D-glucoside (CG) are used as the markers for the quality control of AR and its products in the Chinese Pharmacopoeia. However, in the raw materials, malic acid esters of the CG and acetate esters of the astragaloside are easily decomposed into CG and AG IV during storage and processing of AR to make extracts for various preparations. The thermal stability of the isoflavonoids and astragalosides in decoction was studied. The level of CG and astragalosides (AG I/AG II/AG IV) was strongly affected by prolonged heat during processing, while calycosin was stable in the conditions. Also the major astragalosides in AR could fully converted into AG IV which eventually reaches a stable level under certain conditions. With calycosin and AG IV as marker components, practical, reproducible, and precise methods were established and applied to the quality analysis of AR from its raw materials to its intermediates and products. This study demonstrates that a full chemical profiles analysis of the whole manufacturing process (from “raw materials—intermediates/extracts—final product”) is important to identify quality markers (Q-markers) and even to establish proper analysis methods for traditional Chinese medicine products.

Xanthine oxidase (XO) inhibition is a major strategy for preventing hyperuricemia and associated comorbidities, such as gout. Alfalfa extract has been demonstrated to possess XO-inhibiting activity; however, the elaborate conventional fraction-by-fraction analyses hindered the identification of the active components. In this study, we established a streamlined approach to rapidly screen, identify, and characterize XO-interacting compounds in alfalfa, by incorporating protein-subtraction, mass profiling, and molecular docking analysis. Crude extract was incubated with or without XO protein before UPLC-ESI-Q-TOF-MS/MS composition profiling. By dereplicating the component profile of XO-subtracted extract from that of untreated extract, the targets were rapidly narrowed down to twelve XO-interacting compounds, regarded as potential xanthine oxidase inhibitors (XOIs). Molecular docking analysis revealed that nine of these compounds, namely salicylic acid, tricin 7-O-glucuronopyranoside, chrysoeriol-7-glucoside, ferulic acid, apigenin 7-O-β-glucuronopyranoside, apigenin, tricin, chrysoeriol, and liquiritigenin, exhibited high affinity with XO, and depicted the possible mechanisms of inhibition. In vitro bioassay further verified the XO inhibitory activities of selected compounds, among which apigenin, chrysoeriol and liquiritigenin were more potent XO inhibitors (XOIs), with IC50 of 0.25, 0.5 and 1 µM, respectively, compared to allopurinol (IC50 = 1.41 µM), the well-known XO-inhibiting drug. Together, the results demonstrated that alfalfa is a promising natural source for potent XOIs which might be applied for nutraceuticals development and that the approach used is applicable for efficient screening, identification, and mechanistic analyses of enzyme-inhibiting compounds from plant-based resources.

Based on the hypothesis that variation of the metabolomes of latex is a response to selective pressure and should thus be affected differently from other organs, their variation could provide insight into the defensive chemical selection of plants. Metabolic profiling was utilized to compare tissues of Euphorbia species collected in various regions. The metabolic variation of latexes was much more limited than that of other organs. In all of the species, the levels of polyisoprenes and terpenoids were found to be much higher in latexes than in leaves and roots. Polyisoprenes were also observed to physically delay the contact and growth of pathogens with plant tissues. A secondary barrier composed of terpenes and, in particular, 24-methylenecycloartanol, exhibited antifungal activity. These results, together with the known roles of the enzymes also present in latexes, demonstrate that they are part of a cooperative defense system that comprises both biochemical and physical elements.

In recent years, chronic degenerative diseases such as certain types of cancers, are becoming an evident issue. DNA damage has been for long recognized as a causal factor for cancer development because mutations or chromosomal aberrations affect oncogenes and tumor suppressor genes leading cells to malignant transformation and to the subsequent cancerous growth. Medicinal plants are often used for the prevention or treatment of various diseases with great scientific interest. Among the medicinal plants distributed in the Mediterranean region, Fraxinus angustifolia Vahl. has been used in traditional medicine for its remarkable curative properties. However, in spite of this popularity, little works have been performed on the activity so that further studies should be performed to investigate in depth the antimutagenic, antigenotoxic and antiproliferative activities of the plant. Thus, the present study was aimed to the evaluation of the potential antimutagenic, antigenotoxic and antiproliferative properties of leaves and stem bark extracts of this well-known tree. Antimutagenic activity was evaluated by Salmonella mutagenicity assay in Salmonella typhimurium TA98 and TA100 strains. The antigenotoxic potential was assessed by umu test in the strain of S. typhimurium TA1535/pSK1002. Antiproliferative activity was studied on human hepatoblastoma (HepG-2) and on breast adenocarcinoma (MCF-7) cell lines by MTT assay. Furthermore, the antiproliferative activity observed on cancer cells was compared with that on the human normal-like fibroblasts (TelCOFS02MA) and the selectivity index was calculated to understand if extracts were able to exert selective toxicity towards cancer cells. Moreover, phenolic compounds are plant substances with a large spectrum of biochemical activities with antioxidant, antimutagenic and anticarcinogenic effects. Based on the strong evidence of biological activities of phenolic compounds, the study was focused on the determination of total phenolics and flavonoids contents, and the phytochemical composition of the extracts assessed by LC/MS. The ethanol extracts of both leaves and stem barks showed significant from moderate to strong antimutagenic and antigenotoxic effects. In addition, selective cytotoxicity towards cancer cells was shown by ethanolic leaves extract and aqueous/chloroform leaves and stem bark extracts. The latter showed high levels of total phenolic contents among all the other extracts. Identified phenylethanoids (calceolariosides, verbascoside) and secoiridoids (oleuropein and ligstroside) could be responsible for the demonstrated broad spectrum of healthy properties.

Natural deep eutectic solvents (NADES) are a type of ionic liquid (IL) or deep eutectic solvent (DES), the ingredients of which are exclusively natural products (non-toxic and environmentally friendly). Here, we explore the potential of NADES as an alternative to conventional organic solvents (e.g., aqueous methanol or ethanol) for the extraction of flavonoids from Scutellaria baicalensis stem bark to investigate their extractability depending on structural variation. Four NADES, each containing citric acid in combination with &beta, alanine, glucose, xylitol, or proline (at a molar ratio of 1:1), and a variable amount of water, were used to extract the flavonoid aglycones: baicalein (1), scutellarein (3), wogonin (5), and oroxylin A (7), and their glycosides, baicalin (2), scutellarin (4), wogonoside (6) and oroxyloside (8) from the powdered bark of S. baicalensis. The chemical profile and yield of the extracts were determined using HPTLC and HPLC. The extractability of individual flavonoids was found to be influenced by the concentration of water (20&ndash, 60%, w/w) in the NADES. Among the tested flavonoids, the extraction yield of baicalein (1), scutellarein (3), wogonin (5), oroxylin A (7) with NADES was 2 to 6 times that of aqueous methanol. However, the amount of their corresponding glycosides (baicalin (2), wogonoside (6) and oroxyloside (8)) extracted with NADES was only 1.5&ndash, 1.8 times higher than with aqueous methanol. Interestingly, the more hydrophilic glycosides were less extracted than their corresponding aglycones despite the high hydrophilicity of the NADES. These results prove that NADES may be used for extraction of compounds with a wide range of hydrophilicity.

Natural deep eutectic solvents (NADES) have been proposed as a third liquid phase in nature as they can explain many biochemical processes involving non-lipid and non-water soluble compounds. The NADES ingredients are common cellular ingredients, like polyalcohols, sugars, organic acids and bases, and amino acids. Combinations of such compounds in certain molar ratios are liquids that have shown to solubilize a wide range of natural products that are poorly water-soluble. The NADES have thus been studied for the extraction of a large variety of natural products. The review discusses the potential applications and limitations of NADES as sustainable extraction solvents in analytical chemistry.