Oleanane glycosides from Astragalus tauricolus: isolation and structural elucidation based on a preliminary liquid chromatography-electrospray ionization tandem mass spectrometry profiling

Astraoleanosides E-P, oleanane-type triterpenoid saponins from the aerial parts of Astragalus membranaceus Bunge and their β-glucuronidase inhibitory activity

Historically, Astragalus membranaceus Bunge has been used as a beneficial medicinal plant, particularly in the Asian traditional medical systems, for the treatment of various human diseases such as stomach ulcers, diarrhea, and respiratory issues associated with phlegm. In this study, a phytochemical characterization of the aerial parts of A. membranaceusled to the isolation of 29 oleanane-type triterpenoid saponins, including 11 new compounds named astraoleanosides E-P (6-9, 13, 14, 18-22), as well as 18 known ones. The structures of these compounds were elucidated using nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry. Among them, astraoleanoside H (9) and cloversaponin III (15) demonstrated the most potent β-glucuronidase inhibitory activities, with IC50 values of 21.20 ± 0.75 and 9.05 ± 0.47 µM, respectively, compared to the positive control d-saccharic acid 1,4-lactone (IC50 = 20.62 ± 1.61 µM). Enzyme kinetics studies were then conducted to investigate the type of inhibition exhibited by these active compounds. In addition, the binding mechanism, key interactions, binding stability, and dynamic behavior of protein-ligand complexes were investigated through in silico approaches, such as molecular docking and molecular dynamics simulations. These findings highlight the promising potential of triterpenoid saponins from A. membranaceus as lead compounds for β-glucuronidase inhibitors, offering new possibilities for the development of therapeutic agents targeting various diseases where β-glucuronidase plays a crucial role.

Functional characterization of a cycloartenol synthase and four glycosyltransferases in the biosynthesis of cycloastragenol-type astragalosides from Astragalus membranaceus

Astragalosides are the main active constituents of traditional Chinese medicine Huang-Qi, of which cycloastragenol-type glycosides are the most typical and major bioactive compounds. This kind of compounds exhibit various biological functions including cardiovascular protective, neuroprotective, etc. Owing to the limitations of natural sources and the difficulties encountered in chemical synthesis, re-engineering of biosynthetic machinery will offer an alternative and promising approach to producing astragalosides. However, the biosynthetic pathway for astragalosides remains elusive due to their complex structures and numerous reaction types and steps. Herein, guided by transcriptome and phylogenetic analyses, a cycloartenol synthase and four glycosyltransferases catalyzing the committed steps in the biosynthesis of such bioactive astragalosides were functionally characterized from Astragalus membranaceus. AmCAS1, the first reported cycloartenol synthase from Astragalus genus, is capable of catalyzing the formation of cycloartenol; AmUGT15, AmUGT14, AmUGT13, and AmUGT7 are four glycosyltransferases biochemically characterized to catalyze 3-O-xylosylation, 3-O-glucosylation, 25-O-glucosylation/O-xylosylation and 2'-O-glucosylation of cycloastragenol glycosides, respectively. These findings not only clarified the crucial enzymes for the biosynthesis and the molecular basis for the structural diversity of astragalosides in Astragalus plants, also paved the way for further completely deciphering the biosynthetic pathway and constructing an artificial pathway for their efficient production.

Identification of azukisapogenol triterpenoid saponins from Oxytropis hirta Bunge and their aphicidal activities against pea aphid Acyrthosiphon pisum Harris

BACKGROUND

Acyrthosiphon pisum Harris is the most destructive pest worldwide because of its ability to feed on plants directly and transmit plant viruses as a vector. This study aims to identify triterpenoid saponins from Oxytropis hirta Bunge as biopesticides to control aphids.

RESULTS

Three new azukisapogenol triterpenoid saponins (1-3), a new pinoresinol lignan glycoside (8), and four known saponins (4-7) were identified from the root of O. hirta. Compounds 4-7 displayed significant aphicidal activities against A. pisum with oral toxicities (LC₅₀  = 51.10-147.43 μg/mL, 72 h), deterrent effects (deterrence index = 1.00, 100-200 μg/mL, 24 h), and aphid reproduction inhibitory effects (inhibition rates = 75.91-86.73%, 400 μg/mL, 24 h), respectively. The carboxyl groups at C-3 GlcA and C-30 were functional groups for their aphicidal activities. The toxic symptoms caused by the optimal 5 involved insect body-color changes from light green to dark or gray-green, and then brown until death. The intestinal cavity, apical microvilli, nuclei, mitochondria, and electron dense granules in the midgut tissues of A. pisum were the target sites showing aphicidal activity. The suppression of pepsin and α-amylase, and the activation of lipase and trypsin could be the signs of organelle damage in the midgut tissues.

CONCLUSION

Azukisapogenol triterpenoid saponins from O. hirta could be used as biopesticides to control aphids for their multiple efficacies, including oral toxicity, deterrent activity, and reproduction inhibitory activity. The toxic symptoms involved insect body-color changes. Midgut tissues and their related enzymes were the targets for saponins showing aphicidal activities. © 2022 Society of Chemical Industry.

Astragalus species: Insights on its chemical composition toward pharmacological applications

Astragalus L. is widely distributed throughout the temperate regions of Europe, Asia, and North America. The genus is widely used in folk medicine and in dietary supplements, as well as in cosmetics, teas, coffee, vegetable gums, and as forage for animals. The major phytoconstituents of Astragalus species with beneficial properties are saponins, flavonoids, and polysaccharides. Astragalus extracts and their isolated components exhibited promising in vitro and in vivo biological activities, including antiaging, antiinfective, cytoprotective, antiinflammatory, antioxidant, antitumor, antidiabesity, and immune-enhancing properties. Considering their proven therapeutic potential, the aim of this work is to give a comprehensive summary of the Astragalus spp. and their active components, in an attempt to provide new insight for further clinical development of these xenobiotics. This is the first review that briefly describes their ethnopharmacology, composition, biological, and toxicological properties.

Polyphenol Profile and Biological Activity Comparisons of Different Parts of Astragalus macrocephalus subsp. finitimus from Turkey

The members of the genus Astragalus have great interest as traditional drugs in several folk systems including Turkey. In this sense, the present paper was aimed to explore the biological properties and chemical profiles of different parts (aerial parts, leaves, flowers, stems, and roots) of A. macrocephalus subsp. finitimus. Antioxidant (radical quenching, reducing power, and metal chelating) and enzyme inhibitory (α-amylase and tyrosinase) effects were investigated for biological properties. Regarding chemical profiles, individual phenolic compounds were detected by LC-MS, as well as total amounts. The leaves extract exhibited the strongest antioxidant abilities when compared with other parts. However, flowers extract had the best metal chelating ability. Hyperoside, apigenin, p-coumaric, and ferulic acids were identified as main compounds in the tested parts. Regarding enzyme inhibitory properties, tyrosinase inhibitory effects varied from IC₅₀: 1.02 to 1.41 mg/mL. In addition, the best amylase inhibition effect was observed by leaves (3.36 mg/mL), followed by aerial parts, roots, stems, and flowers. As a result, from multivariate analysis, the tested parts were classified in three cluster. Summing up the results, it can be concluded that A. macrocephalus subsp. finitimus could be a precious source of natural bioactive agents in pharmaceutical, nutraceutical, and cosmeceutical applications.

Plant-Based Phytochemicals as Possible Alternative to Antibiotics in Combating Bacterial Drug Resistance

The unprecedented use of antibiotics that led to development of resistance affect human health worldwide. Prescription of antibiotics imprudently and irrationally in different diseases progressed with the acquisition and as such development of antibiotic resistant microbes that led to the resurgence of pathogenic strains harboring enhanced armors against existing therapeutics. Compromised the treatment regime of a broad range of antibiotics, rise in resistance has threatened human health and increased the treatment cost of diseases. Diverse on metabolic, genetic and physiological fronts, rapid progression of resistant microbes and the lack of a strategic management plan have led researchers to consider plant-derived substances (PDS) as alternative or in complementing antibiotics against the diseases. Considering the quantitative characteristics of plant constituents that attribute health beneficial effects, analytical procedures for their isolation, characterization and phytochemical testing for elucidating ethnopharmacological effects has being worked out for employment in the treatment of different diseases. With an immense potential to combat bacterial infections, PDSs such as polyphenols, alkaloids and tannins, present a great potential for use, either as antimicrobials or as antibiotic resistance modifiers. The present study focuses on the mechanisms by which PDSs help overcome the surge in resistance, approaches for screening different phytochemicals, methods employed in the identification of bioactive components and their testing and strategies that could be adopted for counteracting the lethal consequences of multidrug resistance.

Triterpene glycosides from Silene odontopetala

Silene species are known for their use in traditional medicine in treating several diseases. To the authors' knowledge there is no report on the chemical composition of S. odontopetala. Therefore, the phytochemical investigation of the methanol extract of S. odontopetala was carried out, leading to the isolation of six undescribed oleanane-type glycosides along with the known saponin azukisaponin IV. Their structures were elucidated by the analysis of 1D and 2D-NMR experiments, along with mass spectrometry analysis. The cytotoxic activity of oleanane-type saponins was evaluated against a small panel of cancer cell lines, including PC-3 (prostate carcinoma cells), MCF-7 (breast cancer cells), A549 (alveolar basal carcinoma cells), and HeLa (cervical carcinoma cells). Furthermore, the activity of isolated compounds against a normal cell line HEK-293, used for assessing their cytotoxicity, was evaluated.

Hyaluronidase inhibitory saponins and a trypanocidal isoflavonoid from the aerial parts of Oxytropis lanata

A chemical examination of an extract from the aerial part of Oxytropis lanata led to the isolation and identification of 36 compounds, including saponins, isoflavonoids, oxazoles, and glycosides. The three among them were previously unreported oleanane-type saponins. In trypanocidal screening, 5,7,4'-trihydroxyisoflavone showed inhibitory activity against Trypanosoma congolense (IC₅₀ = 10.5 μM), the causative agent of African trypanosomosis in animals; this activity was similar to that of active compounds from the roots of this plant. O. lanata is known to be a traditional medicinal plant in Mongolia for the treatment of inflammatory diseases. The anti-hyaluronidase effect of saponins 3, 5, 8, and 9, (IC₅₀ = 0.15-0.22 mM) was stronger than that of sodium cromoglicate, which was used as a reference drug (IC₅₀ = 0.37 mM). The chemical structures of the new saponins were determined based on HRFABMS, ¹H and ¹³C NMR, ¹H-¹H COSY, HMQC, HMBC, and ROESY spectroscopic data along with chemical procedures.

In depth LC-ESIMSn-guided phytochemical analysis of Ziziphus jujuba Mill. leaves

Ziziphus jujuba Mill. leaves are receiving a great attention for their ability to improve sleep, exerting beneficial effects for both the heart and the central nervous system. With the aim to obtain a comprehensive analysis of the specialised metabolites occurring in the leaves of Z. jujuba, a LC-ESI/(HR)Orbitrap/MS profile in negative ion mode of the methanol extract was carried out. The LC-MS profile guided the isolation of 42 compounds, of which the structures were elucidated by 1D and 2D-NMR experiments. Based on this approach, 2 previously unreported dammarane-type saponins have been characterized along with flavonoid derivatives, dammarane-type saponins and triterpenic acids. Dammarane-type saponins were tested for their cytotoxic activity against A549 and HeLa cancer cell lines. None of the tested compounds, in a range of concentrations between 12.5 and 100 μM, caused a significant reduction of the cell number. This work provides a deep insight on the chemistry of the leaves of Z. jujuba and could be useful for further biological studies aimed at identifying phytochemicals contributing to the health benefits attributed to this herbal drug.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014

This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.

Rapid characterization of chemical constituents and metabolites of Qi-Jing-Sheng-Bai granule by using UHPLC-Q-TOF-MS

Qi-Jing-Sheng-Bai granule is an effective traditional Chinese medicine formula that has been widely used for the treatment of leukopenia post radiotherapy or chemotherapy. However, its chemical constituents were still unclear, which hindered interpreting bioactive constituents and studying integrative mechanisms. In this study, we developed a three-step strategy to characterize the chemical constituents and metabolites of Qi-Jing-Sheng-Bai by using ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. As a result, a total of 143 compounds, including 56 flavonoids, 51 saponins, and 36 other compounds, of which contained six pairs of isomers, were tentatively identified and characterized via reference standards and by comparing mass spectrometry data with literature. After oral administration of 15 g/kg Qi-Jing-Sheng-Bai, a number of 42 compounds including 24 prototype compounds and 18 metabolites have been detected in the serum of rats. This work serves as the first reference for Qi-Jing-Sheng-Bai chemical components and metabolites. Moreover, it provided a rapid and valid analytical strategy for characterization of the chemical compounds and metabolites of traditional Chinese medicine formula.

Chemical metabolome assay by high-resolution Orbitrap mass spectrometry and assessment of associated antitumoral activity of Actinocephalus divaricatus

RATIONALE

Actinocephalus divaricatus (Eriocaulaceae) is an important source of income for rural communities as it is sold as an ornamental plant. To date, no investigation has been conducted concerning the chemical composition and biological studies of the aerial parts of A. divaricatus.

METHODS

The methanolic extract of the aerial parts of this species was chemically characterized. We applied an analytical dereplication approach based on Liquid Chromatography coupled to High-Resolution Orbitrap Mass Spectrometry in order to develop, identify and define rapidly the metabolite fingerprint of the aerial parts of A. divaricatus. Biological in vitro antitumor tests were undertaken using breast and lung cell lines of mice and humans.

RESULTS

High-Resolution Mass Spectrometry (HRMS) allowed the fast determination of 30 compounds, which comprised three different classes of compounds: naphthopyranones, flavonoids and saponins. Chromatographic fractionation of the crude methanolic extract validated these results, since it led to the isolation of compounds belonging to the aforementioned classes of compounds, including new acyl glycosylated flavonoids (6-hydroxy-7-methoxyquercetin-3-O-(2"-O-acetyl)-β-D-glucopyranoside and 6-hydroxy-7-methoxyquercetin-3-O-(6"-O-acetyl)-β-D-glucopyranoside), which were fully characterized by Nuclear Magnetic Resonance and Mass Spectrometry experiments, and a known triterpenic saponin (3-O-β-D-glucuronopyranosyl-30-norolean-12,20(29)-dien-28-O-β-D-glucopyranosyl ester). Biological assays indicated that the methanolic extract of the capitula exhibited the best in vitro cytotoxicity against MCF7 cells (human breast cancer).

CONCLUSIONS

The HRMS technique enabled us to identify several classes of compounds. In addition, saponins were identified for the first time in plants belonging to the Eriocaulaceae family. Thus, the essential contribution of this work lies in the new elements it brings to the taxonomic discussion which the Actinocephalus genus as a distinct genus of the Paepalanthus. The results obtained show that the methanolic extract of the capitula could be a promising source of bioactive fractions and/or compounds that may contribute towards breast cancer treatment.

Secondary metabolites from Astragalus karjaginii BORISS and the evaluation of their effects on cytokine release and hemolysis

A new cycloartane sapogenol and a new cycloartane xyloside were isolated from Astragalus karjaginii BORISS along with thirteen known compounds. The structures of the new compounds were established as 3-oxo-6α,16β,24(S),25-tetrahydroxycycloartane (1) and 6-O-β-d-xylopyranosyl-3β,6α,16β,24(S),25-pentahydroxycycloartane (2) by 1D- and 2D-NMR experiments as well as ESIMS and HRMS analyses. The presence of the keto function at position 3 was reported for the first time for cyclocanthogenol sapogenin of Astragalus genus. In vitro immunomodulatory effects of the new compounds (1 and 2) along with the n-BuOH and MeOH extracts of A. karjaginii at two different doses (3 and 6μg) were tested on human whole blood for in vitro cytokine release (IL-2, IL-17A and IFN-γ) and hemolytic activities. The results confirmed that compound 2, a monodesmosidic saponin, had the strongest effect on the induction of both IL-2 (6μg, 6345.41±0.12pg/mL (×5), P<0.001) and a slight effect upon IL-17A (3μg, 5217.85±0.72pg/mL, P<0.05) cytokines compared to the other test compounds and positive controls (AST VII: Astragaloside VII; and QS-21: Quillaja saponin 21). All tested extracts and molecules also induced release of IFN-γ remarkably ranging between 5031.95±0.05pg/mL, P<0.001 for MeOH extract (6μg) and 5877.08±0.06pg/mL, P<0.001 for compound 1 (6μg) compared to QS-21 (6μg, 5924.87±0.1pg/mL, P<0.001). Administration of AST VII and other test compounds did not cause any hemolytic activity, whereas QS-21 resulted a noteworthy hemolysis.

Triterpenoids

Covering: 2013. Previous review: Nat. Prod. Rep., 2015, 29, 1028-1065This review covers the isolation and structure determination of triterpenoids reported during 2013 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 350 references are cited.

Compounds from the pods of Astragalus armatus with antioxidant, anticholinesterase, antibacterial and phagocytic activities

CONTEXT

The phytochemical study and biological activities of Astragalus armatus Willd. subsp. numidicus (Fabaceae) pods, an endemic shrub of Maghreb, are reported.

OBJECTIVE

This study isolates the secondary metabolites and determines the bioactivities of Astragalus armatus pods.

MATERIALS AND METHODS

The chloroform, ethyl acetate and n-butanol extracts of hydro-ethanolic extracts were studied. Antioxidant activity was investigated using DPPH and ABTS radical scavenging, CUPRAC and ferrous chelating assays at concentrations ranging from 3 to 200 μg/mL. Anticholinesterase activity was determined against acetylcholinesterase and butyrylcholinesterase enzymes at 50, 100 and 200 μg/mL. Antibacterial activity was performed according to minimum inhibitory concentration (MIC) method. Carbon clearance method in albino mice was used for the phagocytic activity at concentrations 50, 70 and 100 mg/kg body weight. Spectroscopic techniques were used to elucidate the compounds.

RESULTS

Ethyl acetate extract afforded a flavonoid (1) while the n-butanol extract gave four flavonoids (2-5), a cyclitol (6) and a cycloartane-type saponin (7). The ethyl acetate extract exhibited highest antioxidant activity in DPPH (IC₅₀: 67.90 ± 0.57 μg/mL), ABTS (IC₅₀: 11.30 ± 0.09 μg/mL) and CUPRAC (A_0.50: 50.60 ± 0.9 μg/mL) assays. The chloroform extract exhibited the best antibacterial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, each with 80 μg/mL MIC values. The n-butanol extract enhanced phagocytic activity.

DISCUSSION AND CONCLUSION

Isorhamnetin (1), isorhamnetin-3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-galactopyranoside (2), isorhamnetin-3-O-β-d-apiofuranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)]-β-d-galactopyranoside (3), kaempferol-3-O-(2,6-di-O-α-l-rhamnopyranosyl)-β-d-galactopyranoside (4), kaempferol-3-O-(2,6-di-O-α-l-rhamnopyranosyl)-β-d-glucopyranoside (5), pinitol (6) and cyclomacroside D (7) were isolated whereas 1, 2, 6 and 7 are reported for the first time from A. armatus.

Secondary Metabolites from Astragalus lycius and Their Cytotoxic Activities

Eight known secondary metabolites were isolated from the methanolic extract of the whole plant of Astragalus lycius Boiss. They were identified as 5,5′-dihydroxy-3′-methoxy-isoflavone-7- O-β-D-glucoside (1), genistin (2), sissotrin (3), 5,4′-dimethoxy-isoflavone-7- O-β-D-glucopyranoside (4), (7 S,8 R)-5-methoxydehydrodiconiferyl alcohol-4- O-β-D-glucopyranoside (5), 4- O-lariciresinol-glucoside (6), 2-phenylethyl-β-D-glucopyranoside (7) and β-sitosterol-3- O-β-D-glucopyranoside (8) by spectroscopic methods including 1H- and 13C-NMR and HR-MS experiments, and by comparison with literature values. Compounds 1–7 are reported for the first time from Astragalus taxa. All of the compounds were tested for their cytotoxic activities against a number of cancer cell lines. Among them, only 6 exhibited significant activity against human colon carcinoma (HT-29) at 2.69 μM concentration.

Quali-quantitative analysis of the phenolic fraction of the flowers of Corylus avellana, source of the Italian PGI product "Nocciola di Giffoni": Isolation of antioxidant diarylheptanoids

There is only limited information available on the chemical composition of the non-edible parts of Corylus avellana, source of the Italian PGI product "Nocciola di Giffoni" (hazelnut). An initial LC-MS profile of the methanolic extract of the male flowers of C. avellana, cultivar 'Tonda di Giffoni' led to the isolation of 12 compounds, of which the structures were elucidated by NMR spectroscopy. These were identified as three previously undescribed diarylheptanoids, named giffonins Q-S, along with nine known compounds. Furthermore, the quantitative determination of the main compounds occurring in the methanolic extract of C. avellana flowers was carried out by an analytical approach based on LC-ESI(QqQ)MS, using the Multiple Reaction Monitoring (MRM) experiment. In order to explore the antioxidant ability of C. avellana flowers, the methanolic extract and the isolated compounds were evaluated for their inhibitory effects on human plasma lipid peroxidation induced by H2O2 and H2O2/Fe(2+), by measuring the concentration of TBARS.

Giffonins J-P, Highly Hydroxylated Cyclized Diarylheptanoids from the Leaves of Corylus avellana Cultivar "Tonda di Giffoni"

Two new diaryl ether heptanoids, giffonins J and K (1 and 2), along with five new diarylheptanoids, giffonins L-P (3-7), were isolated from a methanol extract of the leaves of Corylus avellana cultivar "Tonda di Giffoni". These compounds were identified as highly hydroxylated cyclized diarylheptanoids by 1D- and 2D-NMR experiments. The relative configurations of giffonins J-P (1-7) were established by a combined QM (quantum mechanical)/NMR approach, comparing the experimental (13)C/(1)H NMR chemical shift data and the related predicted values. The cytotoxic activities of giffonins J-P (1-7) were evaluated against the human osteosarcoma U2Os and SAOs cell lines.

Discovery and resupply of pharmacologically active plant-derived natural products: A review

Medicinal plants have historically proven their value as a source of molecules with therapeutic potential, and nowadays still represent an important pool for the identification of novel drug leads. In the past decades, pharmaceutical industry focused mainly on libraries of synthetic compounds as drug discovery source. They are comparably easy to produce and resupply, and demonstrate good compatibility with established high throughput screening (HTS) platforms. However, at the same time there has been a declining trend in the number of new drugs reaching the market, raising renewed scientific interest in drug discovery from natural sources, despite of its known challenges. In this survey, a brief outline of historical development is provided together with a comprehensive overview of used approaches and recent developments relevant to plant-derived natural product drug discovery. Associated challenges and major strengths of natural product-based drug discovery are critically discussed. A snapshot of the advanced plant-derived natural products that are currently in actively recruiting clinical trials is also presented. Importantly, the transition of a natural compound from a "screening hit" through a "drug lead" to a "marketed drug" is associated with increasingly challenging demands for compound amount, which often cannot be met by re-isolation from the respective plant sources. In this regard, existing alternatives for resupply are also discussed, including different biotechnology approaches and total organic synthesis. While the intrinsic complexity of natural product-based drug discovery necessitates highly integrated interdisciplinary approaches, the reviewed scientific developments, recent technological advances, and research trends clearly indicate that natural products will be among the most important sources of new drugs also in the future.

A review of recent research progress on the astragalus genus

Astragalus L., is one of the largest genuses of flowering plants in the Leguminosae family. Roots of A. membranaceus Bge. var. mongholicus (Bge.) Hsiao, A. membranaceus (Fisch.) Bge. and its processed products are listed in the China Pharmacopeia for “qi deficiency” syndrome treatment. However, more and more researches on other species of Astragalus have been conducted recently. We summarize the recent researches of Astragalus species in phytochemistry and pharmacology. More than 200 constituents, including saponins and flavonoids, obtained from 46 species of Astragalus genus were collected for this article. In pharmacological studies, crude extracts of Astragalus, as well as isolated constituents showed anti-inflammatory, immunostimulant, antioxidative, anti-cancer, antidiabetic, cardioprotective, hepatoprotective, and antiviral activities. The goal of this article is to provide an overview of chemical and pharmacological studies on the Astragalus species over the last 10 years, which could be of value to new drug or food supplement research and development.

Saponins with highly hydroxylated oleanane-type aglycones from Silphium asteriscus L

Silphium asteriscus L., commonly known as starry rosinweed, is a plant found in prairies, glades, woodlands and savannas of the southeastern United States. The phytochemical investigation of the methanolic extract of S. asteriscus leaves led to the isolation of eighteen saponins with highly hydroxylated oleanane-type aglycones never reported before. Their structures were elucidated by extensive spectroscopic methods including 1D- ((1)H and (13)C) and 2D-NMR (DQF-COSY, HSQC, HMBC, TOCSY and ROESY) experiments as well as ESIMS analysis. The antiproliferative activity of the isolated compounds was evaluated against three cancer cell lines including Hela (human epitheloid cervix carcinoma), Jurkat cells (leukaemic T-cell line) and DLD-1 (colorectal adenocarcinoma). Compounds 1, 5 and 17 displayed weak activity with IC50 values ranging from 50 to 75 μM.

Triterpene saponins from the aerial parts of Trifolium medium L. var. sarosiense

Seven previously unreported triterpene glycosides (1-7) were isolated from methanol extract of the aerial parts of Trifolium medium var. sarosiense (zigzag clover). Their structures were established by the extensive use of 1D and 2D NMR experiments along with ESI-MS and HRMS analyses. Compounds 1-7 are oleanane derivatives characterized by the presence of a keto group at C-22 of an aglycone and a primary alcoholic function at C-24 and differing functions at C-30. Among these, compounds 1-3 and 6 showed a secondary alcoholic function at C-11, which is methoxylated in compounds 4 and 7. Compound 5 was shown to possess a known aglycone, wistariasapogenol A; however, it is described here for the first time as a saponin constituent of the Trifolium genus. Some aspects of taxonomic classification of zigzag clover are also discussed.

Mass spectrometry and NMR spectroscopy: modern high-end detectors for high resolution separation techniques--state of the art in natural product HPLC-MS, HPLC-NMR, and CE-MS hyphenations

Current natural product research is unthinkable without the use of high resolution separation techniques as high performance liquid chromatography or capillary electrophoresis (HPLC or CE respectively) combined with mass spectrometers (MS) or nuclear magnetic resonance (NMR) spectrometers. These hyphenated instrumental analysis platforms (CE-MS, HPLC-MS or HPLC-NMR) are valuable tools for natural product de novo identification, as well as the authentication, distribution, and quantification of constituents in biogenic raw materials, natural medicines and biological materials obtained from model organisms, animals and humans. Moreover, metabolic profiling and metabolic fingerprinting applications can be addressed as well as pharmacodynamic and pharmacokinetic issues. This review provides an overview of latest technological developments, discusses the assets and drawbacks of the available hyphenation techniques, and describes typical analytical workflows.