Cycloastragenol alleviates airway inflammation in asthmatic mice by inhibiting autophagy.

Cycloastragenol (CAG), a secondary metabolite from the roots of Astragalus zahlbruckneri, has been reported to exert anti­inflammatory effects in heart, skin and liver diseases. However, its role in asthma remains unclear. The present study aimed to investigate the effect of CAG on airway inflammation in an ovalbumin (OVA)­induced mouse asthma model. The current study evaluated the lung function and levels of inflammation and autophagy via measurement of airway hyperresponsiveness (AHR), lung histology examination, inflammatory cytokine measurement and western blotting, amongst other techniques. The results demonstrated that CAG attenuated OVA­induced AHR in vivo. In addition, the total number of leukocytes and eosinophils, as well as the secretion of inflammatory cytokines, including interleukin (IL)­5, IL­13 and immunoglobulin E were diminished in bronchoalveolar lavage fluid of the OVA­induced murine asthma model. Histological analysis revealed that CAG suppressed inflammatory cell infiltration and goblet cell secretion. Notably, based on molecular docking simulation, CAG was demonstrated to bind to the active site of autophagy­related gene 4­microtubule­associated proteins light chain 3 complex, which explains the reduced autophagic flux in asthma caused by CAG. The expression levels of proteins associated with autophagy pathways were inhibited following treatment with CAG. Taken together, the results of the present study suggest that CAG exerts an anti­inflammatory effect in asthma, and its role may be associated with the inhibition of autophagy in lung cells.

Experimental and molecular docking investigation of the inclusion complexes between 20(S)-protopanaxatriol and four modified ß-cyclodextrins.

20(S)-Protopanaxatriol (PPT) is a type of ginsenoside isolated from panax notoginseng or ginseng, which is an essential ingredient in functional food, healthcare products and traditional medicine. However, the research and development of PPT are restricted due to its poor solubility. To circumvent the associated problems, a novel bridged-bis [6-(2,2'-(ethylenedioxy) bis (ethylamine))-6-deoxy-ß-CD] (H4) was successfully synthesized. The four inclusion complexes of the mono-[6-(1,4-butanediamine)-6-deoxy-ß-CD] (H1), mono-[6-(2,2'-(ethylenedioxy) bis (ethylamine)-6-deoxy-ß-CD] (H2) and their corresponding bridged bis(ß-CD)s (H3, H4) with PPT were prepared and studied by UV, 1H NMR, 2D ROESY, FT-IR, XRD and SEM technology. The UV-spectrometric titration showed that H1-4 and PPT formed 1:1 inclusion complexes and the binding constants were 297.61, 322.25, 937.88 and 1742 M-1, respectively. It was further revealed that the size/shape-matching relationship, hydrophobic interactions and hydrogen bond interactions play the crucial role in determining the stability of H1-4/PPT inclusion complexes. The solubility of PPT was evidently enhanced by193, 265, 453 and 593 times after the formation of inclusion complexes with H1-4, respectively. Furthermore, molecular docking was used to verify the inclusion mode of H4/PPT inclusion complex and also to investigate the stability of H4/PPT in water phase. The molecular simulation results agreed well with the experimental results. This research provides an effective way to obtain novel PPT-based functional food and healthcare products.

Synthesis and anti-inflammatory activity of saponin derivatives of δ-oleanolic acid.

Pentacyclic triterpenes (PTs) are the active ingredients of many medicinal herbs and pharmaceutical formulations, and are well-known for their anti-inflammatory activity. On the other hand, anti-inflammatory effects of AMP-activated protein kinase (AMPK) have recently drawn much attention. In this study, we found that a variety of naturally occurring PTs sapogenins and saponins could stimulate the phosphorylation of AMPK, and identified δ-oleanolic acid (10) as a potent AMPK activator. Based on these findings, 23 saponin derivatives of δ-oleanolic acid were synthesized in order to find more potent anti-inflammatory agents with improved pharmacokinetic properties. The results of cellular assays showed that saponin 29 significantly inhibited LPS-induced secretion of pro-inflammatory factors TNF-α and IL-6 in THP1-derived macrophages. Preliminary mechanistic studies showed that 29 stimulated the phosphorylation of AMPK and acetyl-CoA carboxylase (ACC). The bioavailability of 29 was significantly improved in comparison with its aglycon. More importantly, 29 showed significant anti-inflammatory and liver-protective effects in LPS/D-GalN-induced fulminant hepatic failure mice. Taken together, PTs saponins hold promise as therapeutic agents for inflammatory diseases.

Complete Bioconversion of Protopanaxadiol-Type Ginsenosides to Compound K by Extracellular Enzymes from the Isolated Strain Aspergillus tubingensis.

A compound K-producing fungus was isolated from meju (fermented soybean brick) and identified as the generally recognized as safe (GRAS) strain Aspergillus tubingensis. The extracellular enzymes obtained after the cultivation of 6 days in the medium with 20 g/L citrus pectin as an inducer showed the highest compound K-producing activity among the inducers tested. Under the optimized conditions of 0.05 mM MgSO4, 55 °C, pH 4.0, 13.4 mM protopanaxadiol (PPD)-type ginsenosides, and 11 mg/mL enzymes, the extracellular enzymes from A. tubingensis completely converted PPD-type ginsenosides in the ginseng extract to 13.4 mM (8.35 mg/mL) compound K after 20 h, with the highest concentration and productivity among the results reported so far. As far as we know, this is the first GRAS enzyme to completely convert all PPD-type ginsenosides to compound K.

Advance in glycosyltransferases, the important bioparts for production of diversified ginsenosides.

Ginsenosides are a series of glycosylated triterpenoids predominantly originated from Panax species with multiple pharmacological activities such as anti-aging, mediatory effect on the immune system and the nervous system. During the biosynthesis of ginsenosides, glycosyltransferases play essential roles by transferring various sugar moieties to the sapogenins in contributing to form structure and bioactivity diversified ginsenosides, which makes them important bioparts for synthetic biology-based production of these valuable ginsenosides. In this review, we summarized the functional elucidated glycosyltransferases responsible for ginsenoside biosynthesis, the advance in the protein engineering of UDP-glycosyltransferases (UGTs) and their application with the aim to provide in-depth understanding on ginsenoside-related UGTs for the production of rare ginsenosides applying synthetic biology-based microbial cell factories in the future.

20S-Protopanaxatriol Ameliorates Hepatic Fibrosis, Potentially Involving FXR-Mediated Inflammatory Signaling Cascades.

Ginseng has been used as a functional food and tonic for enhancing immune power. Here, the potential protective effect of 20S-protopanaxatriol (M4), the metabolite of protopanaxatriol, against hepatic fibrosis is investigated, which could provide nutritional interventions for disease treatment. M4 could inhibit extracellular matrix (ECM) deposition and reduce the levels of proinflammatory cytokines such as caspase 1, interleukin 1 ß (IL-1ß), interleukin 1 receptor type 1 (IL1R1), and interleukin 6 (IL-6). M4 also significantly increased the expression of farnesoid X receptor (FXR), suppressed the purinergic ligand-gated ion channel 7 receptor (P2X7r) signaling pathway, and works as an FXR agonist, GW4064. In thioacetamide (TAA)-induced mice, M4 could attenuate the histopathological changes and significantly regulate the expression levels of FXR and P2X7r. M4 ameliorated TAA-induced hepatic fibrosis due to the reduction of P2X7r secretion, inhibition of hepatic stellate cell (HSCs) activation, and inflammation, which were all associated with FXR activation. Hence, M4 might be useful a nutritional preventive approach in antihepatic fibrosis and antihepatic inflammation.

Ginsenoside metabolite 20(S)­protopanaxadiol promotes neural stem cell transition from a state of proliferation to differentiation by inducing autophagy and cell cycle arrest.

20(S)­Protopanaxadiol (PPD) is an active ginseng metabolite and is the final form of protopanaxadiol saponins metabolized by human intestinal microflora. The neuroprotective effects and mechanisms underlying PPD on neural stem cells (NSCs) are not completely understood. The aim of the present study was to assess the effects of PPD on the proliferation and differentiation of neural stem cells. In the present study, following treatment with different concentrations of PPD for 24 h, the percentage of BrdU­positive cells decreased significantly with increasing concentrations of PPD. Moreover, flow cytometric analysis results indicated that PPD treatment increased the proportion of cells in the G0/G1 and G2/M phase and decreased the proportion of cells in the S phase. The activation of autophagy, determined by an increased number of autophagic vacuoles and light chain 3 lipidation, was associated with an increase in the expression of the neuronal marker tubulin­ß3 following PPD treatment. PPD also partially rescued NSCs from the inhibitory effects of the autophagic inhibitor wortmannin, suggesting that the effect of PPD on NSC differentiation was associated with autophagy. Collectively, the results indicated that PPD promoted the transition of NSCs from a state of proliferation to differentiation through the induction of autophagy and cell cycle arrest. Therefore, the present study may provide a basis for the development of regenerative therapies based on ginsenoside, an approved and safe drug.

Dammarane-type leads panaxadiol and protopanaxadiol for drug discovery: Biological activity and structural modification.

Based on the definite therapeutic benefits, such as neuroprotective, cardioprotective, anticancer, anti-diabetic and so on, the Panax genus which contains many valuable plants, including ginseng (Panax ginseng C.A. Meyer), notoginseng (Panax notoginseng) and American ginseng (Panax quinquefolius L.), attracts research focus. Actually, the biological and pharmacological effects of the Panax genus are mainly attributed to the abundant ginsenosides. However, the low membrane permeability and the gastrointestinal tract influence seriously limit the absorption and bioavailability of ginsenosides. The acid or base hydrolysates of ginsenosides, 20 (R,S)-panaxadiol and 20 (R,S)-protopanaxadiol showed improved bioavailability and diverse pharmacological activities. Moreover, relative stable skeletons and active hydroxyl group at C-3 position and other reactive sites are suitable for structural modification to improve biological activities. In this review, the pharmacological activities of panaxadiol, protopanaxadiol and their structurally modified derivatives are comprehensively summarized.

Molecular Insight into Stereoselective ADME Characteristics of C20-24 Epimeric Epoxides of Protopanaxadiol by Docking Analysis.

Chirality is a common phenomenon, and it is meaningful to explore interactions between stereoselective bio-macromolecules and chiral small molecules with preclinical and clinical significance. Protopanaxadiol-type ginsenosides are main effective ingredients in ginseng and are prone to biotransformation into a pair of ocotillol C20-24 epoxide epimers, namely, (20S,24S)-epoxy-dammarane-3,12,25-triol (24S-PDQ) and (20S,24R)-epoxy dammarane-3,12,25-triol (24R-PDQ) that display stereoselective fate in vivo. However, possible molecular mechanisms involved are still unclear. The present study aimed to investigate stereoselective ADME (absorption, distribution, metabolism and excretion) characteristics of PDQ epimers based on molecular docking analysis of their interaction with some vital proteins responsible for drug disposal. Homology modeling was performed to obtain 3D-structure of the human isoenzyme UGT1A8, while calculation of docking score and binding free energy and ligand-protein interaction pattern analysis were achieved by using the Schrödinger package. Stereoselective interaction was found for both UGT1A8 and CYP3A4, demonstrating that 24S-PDQ was more susceptible to glucuronidation, whereas 24R-PDQ was more prone to oxidation catalyzed by CYP3A4. However, both epimers displayed similarly strong interaction with P-gp, a protein with energy-dependent drug-pump function, suggesting an effect of the dammarane skeleton but not C-24 stereo-configuration. These findings provide an insight into stereo-selectivity of ginsenosides, as well as a support the rational development of ginseng products.

In Vitro Permeability of Saponins and Sapogenins from Seed Extracts by the Parallel Artificial Membrane Permeability Assay: Effect of in Vitro Gastrointestinal Digestion.

The permeability of saponins and sapogenins from fenugreek and quinoa extracts, as well as dioscin and diosgenin, was evaluated by the parallel artificial membrane permeability assay (PAMPA). The effect of the digestion process on permeability was determined, with previous development of a gastrointestinal process coupled to PAMPA. Saponins from both seeds displayed a moderate-to-poor permeability (>1 × 10-6 cm/s), although the digestion enhanced their permeability values in the order of 10-5 cm/s (p < 0.001). Sapogenins exhibited a similar permeability to that of saponins, although the digestion enhanced the permeability of sapogenins from quinoa (1.14 ± 0.47 × 10-5 cm/s) but not from fenugreek (2.33 ± 0.99 × 10-6 cm/s). An overall positive impact of coexisting lipids on the permeability was evidenced. PAMPA is shown as a useful, rapid, and easy tool for assessing the permeability of bioactive compounds from complex matrices, with the previous gastrointestinal process being a relevant step.

Biocatalytic synthesis of ginsenoside Rh2 using Arabidopsis thaliana glucosyltransferase-catalyzed coupled reactions.

Ginsenoside Rh2, a rare protopanaxadiol (PPD)-type triterpene saponin isolated from Panax ginseng, exhibits notable anticancer and immune-system-enhancing activities. Glycosylation catalyzed by uridine diphosphate-dependent glucosyltransferase (UGT) is the final biosynthetic step of ginsenoside Rh2. In this study, UGT73C5 isolated from Arabidopsis thaliana was demonstrated to selectively transfer a glucosyl moiety to the C3 hydroxyl group of PPD to synthesize ginsenoside Rh2. UGT73C5 was coupled with sucrose synthase (SuSy) from A. thaliana to regenerate costly uridine diphosphate glucose (UDPG) from cheap sucrose and catalytic amounts of uridine diphosphate (UDP). The UGT73C5/SuSy ratio, temperature, pH, cofactor UDP, and PPD concentrations for UGT73C5-SuSy coupled reactions were optimized. Through the stepwise addition of PPD, the maximal ginsenoside Rh2 production was 3.2 mg mL-1, which was the highest yield reported to date. These promising results provided an efficient and cost-effective approach to semisynthesize the highly valuable ginsenoside Rh2.

Distribution of sapogenins in morphological Medicago sativa L. parts: Comparison of various extraction techniques.

Saponins in plant extracts were indirectly determined by estimation of the content of sapogenins. The first step of determination is extraction with high efficiency. One conventional extraction technique (maceration) and two modern ones (accelerated solvent extraction and supercritical fluid extraction) were compared. Methanol and ethanol were used as solvents or co-solvents. The results were supported by statistical analysis. Saponins were extracted from leaves, roots, and sprouts of Medicago sativa. Acid hydrolysis, purification, and determination by high-performance liquid chromatography with evaporative light scattering detector were used. The content of sapogenins was the highest in the roots. Smaller amounts of sapogenins were found in sprouts and the smallest ones in leaves. The main ingredient was medicagenic acid with mean concentration of 621.8 µg/g in roots, 456.7 µg/g in sprouts, and 471.3 µg/g in leaf extract. The highest content of sapogenins in extract was obtained after maceration with methanol; however, this method is nonselective in relation to biologically active compounds. Due to the possibility of using the obtained extracts with sapogenins in the cosmetic or pharmaceutical industry, the selection of extraction techniques and solvents is a very important aspect. Additionally, the chosen technique should be considered eco-friendly and consistent with the assumptions of "green chemistry."

20(S)-Protopanaxadiol Saponins Mainly Contribute to the Anti-Atherogenic Effects of Panax notoginseng in ApoE Deficient Mice.

Atherosclerosis mainly contributes to cardiovascular disease, a leading cause of global morbidity and mortality. Panax notoginseng saponins (PNS) are proved to therapeutically attenuate the formation of atherosclerotic lesions. According to different sapogenin, PNS are generally classified into 20(S)-protopanaxadiol saponins (PDS) and 20(S)-protopanaxatriol saponins (PTS). It was reported that PDS and PTS might exert diverse or even antagonistic bioactivities. In this study, the probable effects of PTS and PDS on atherosclerotic development were investigated and compared in ApoE-deficient mice (ApoE-/-). Male mice were gavaged daily by PNS (200 mg/kg/d), PTS (100 mg/kg/d), or PDS (100 mg/kg/d), respectively for eight weeks. The treatments of PNS and PDS, but not PTS, showed decreased atherosclerotic lesions in the entire aorta by 45.6% and 41.3%, respectively, as evaluated by an en-face method. Both PNS and PDS can improve the plaque vulnerability, as evidenced by the increased collagen fiber, increased expression of α- smooth muscle actin (α-SMA), and decreased Cluster of differentiation 14 (CD14). Additionally, PDS also inhibit the nuclear factor kappa B (NF-κB)-mediated vascular inflammation in the aorta. In conclusion, PDS, but not PTS, might mainly contribute to the anti-atherosclerosis of P. notoginseng.

In vitro and in silico evaluation of stereoselective effect of ginsenoside isomers on platelet P2Y12 receptor.

BACKGROUND: P2Y12 receptor (P2Y12R) is a newly discovered Gi-coupled ADP receptor that plays critical role in platelet function. Ginsenosides are the main constituents responsible for most of pharmacological actions of ginseng, especially cardio-cerebrovascular protective efficacy that is closely related to the influence on platelet function. HYPOTHESIS/PURPOSE: To explore stereoselective effect of naturally abundant ginsenoside isomers, including the C-20 epimers of protopanaxadiol (PPD), protopanaxatriol (PPT), and their glycosides Rg2, Rg3, Rh1, Rh2 on P2Y12R in platelets. STUDY DESIGN/METHODS: Both in vitro assay and in silico molecular docking study were performed to investigate the stereoselective effects. RESULTS: In vitro assay using washed rat platelets revealed differential effects of ginsenoside isomers on ADP-induced platelet aggregation with the direction and degree of action varying with chemical structures. More to the point, the ginsenoside 20S-Rh2 but not its 20R-epimer was found to be the only one that could significantly promote in vitro platelets aggregation induced by ADP. The correlation analysis demonstrated that ginsenosides may have impact on P2Y12R related platelet functions through a cAMP-dependent pathway. Molecular docking stimulation further indicated that ginsenoside isomers could be potent substrate of P2Y12R with differential protein-ligand interaction that would be responsible for the stereoselective efficacy of C-20 ginsenoside epimers. Hydrogen bonding with Asp266 via the C-20 hydroxyl may provide ginsenosides with promoting effect on ADP-induced platelets aggregation, whereas interactions with Tyr105 could contribute to the promotion of inhibitory efficacy. CONCLUSION: Ginsenosides are potent P2Y12R substrate with stereoselective effects on P2Y12R-related platelet function, which result from their chemical diversity and are closely related to the different interaction ways as P2Y12R ligand.

Not all saponins have a greater antiprotozoal activity than their related sapogenins.

The antiprotozoal effect of saponins varies according to both the structure of the sapogenin and the composition and linkage of the sugar moieties to the sapogenin. The effect of saponins on protozoa has been considered to be transient as it was thought that when saponins were deglycosilated to sapogenins in the rumen they became inactive; however, no studies have yet evaluated the antiprotozoal effect of sapogenins compared to their related saponins. The aims of this study were to evaluate the antiprotozoal effect of eighteen commercially available triterpenoid and steroid saponins and sapogenins in vitro, to investigate the effect of variations in the sugar moiety of related saponins and to compare different sapogenins bearing identical sugar moieties. Our results show that antiprotozoal activity is not an inherent feature of all saponins and that small variations in the structure of a compound can have a significant influence on their biological activity. Some sapogenins (20(S)-protopanaxatriol, asiatic acid and madecassic acid) inhibited protozoa activity to a greater extent than their corresponding saponins (Re and Rh1 and asiaticoside and madecassoside), thus the original hypothesis that the transient nature of the antiprotozoal action of saponins is due to the deglycosilation of saponins needs to be revisited.

Complete Biotransformation of Protopanaxadiol-Type Ginsenosides into 20-O-ß-Glucopyranosyl-20(S)-protopanaxadiol by Permeabilized Recombinant Escherichia coli Cells Coexpressing ß-Glucosidase and Chaperone Genes.

The ginsenoside 20-O-ß-glucopyranosyl-20(S)-protopanaxadiol or compound K is an essential ingredient in functional food, cosmetics, and traditional medicines. However, no study has reported the complete conversion of all protopanaxadiol (PPD)-type ginsenosides from ginseng extract into compound K using whole-cell conversion. To increase the production of compound K from ginseng extract using whole recombinant cells, the ß-glucosidase enzyme from Caldicellulosiruptor bescii was coexpressed with a chaperone expression system (pGro7), and the cells expressing the coexpression system were permeabilized with ethylenediaminetetraacetic acid. The permeabilized cells carrying the chaperone coexpression system showed a 2.6-fold increase in productivity and yield as compared with nontreated cells, and completely converted all PPD-type ginsenosides from ginseng root extract into compound K with the highest productivity among the results reported so far. Our results will contribute to the industrial biological production of compound K.

Genetically modified rice produces ginsenoside aglycone (protopanaxadiol).

MAIN CONCLUSION: Protopanaxadiol is dammarane-type tetracyclic triterpene sapogenin found in ginseng and has a high medicinal values. We successfully constructed transgenic rice producing protopanaxadiol by introducing the ginseng PgDDS and CYP716A47 genes in this crop plant. Protopanaxadiol (PPD), an aglycone of ginsenosides, possesses pleiotropic anticarcinogenesis activities in many cancers. Here, we constructed transgenic rice overexpressing the Panax ginseng dammarenediol-II synthase gene (PgDDS) and protopanaxadiol synthase gene (CYP716A47) driven by a rice endosperm-specific α-globulin promoter. Among more than 50 independent lines, five transgenic lines were selected. The introduction of the genes in the T1 generation of the transgenic lines was confirmed by genomic PCR. The expression of the introduced genes in T2 seeds was confirmed by qPCR. Methanol extracts of transgenic rice grains were analyzed by LC/MS to detect the production of PPD and dammarenediol-II (DD). The production of both PPD and DD was identified not only by comparing the retention times but also mass fraction patterns of authentic PPD and DD standards. The mean concentrations of PPD and DD in rice grains were 16.4 and 4.5 µg/g dry weight, respectively. The invention of genetically engineered rice grains producing PPD and DD can be applied to rice breeding to reinforce new medicinal values.

Efficient separation determination of protopanaxatriol ginsenosides Rg1, Re, Rf, Rh1, Rg2 by HPLC.

An efficient and flexible protocol was developed for simultaneous detection of the ginsenosides Rg1, Re, Rf, Rh1, and Rg2 in ginseng extract. In the analysis of white ginseng that contains no ginsenoside Rf, separation of the remaining ginsenosides was achieved within just 10 min under isocratic chromatographic conditions. For the analysis of red ginseng that contains ginsenoside Rf as a characteristic constituent, the gradient elution conditions were optimized. The method is based on high-pressure liquid chromatography employing a Shiseido UG 80 Capcell Pak NH2(4.6 mm I.D. × 250 mm, 5 µm)column and isocratic elution using acetonitrile (A) and water(B) in a ratio of 76: 24 (v/v), The optimal gradient elution conditions are as follows: 0-3 min, 89% A, 3-25 min, 89-84% A, 25-30 min, 84-82% A, 30-35 min, 82-76% A, then returning to 89% solvent A in 5 min. The flow rate was 0.80 mL min-1. The column temperature was set at 25℃ and the detection wavelength was at 203 nm. The working concentration ranges for ginsenoside Re, Rh1, Rg2, Rg1, and Rf were 0.23-1450.0 mg• L-1, 0.05-1130.0 mg• L-1, 0.11-687.0 mg• L-1, 0.051-1325 mg• L-1, and 0.55-800.0 mg• L-1, respectively. The method was validated for linearity, precision, and accuracy. And the further confirmation of five ginsenosides was conducted by QTOF-MS. Analysis of raw extracts of ginseng, white ginseng, and red ginseng for the five components showed satisfactory recovery.

Microbial transformation of the anti-aging agent cycloastragenol by Mucor racemosus.

The microbial transformation of cycloastragenol (CA) by Mucor racemosus AS 3.20 was investigated. Seven isolated products were identified as (20R,24S)-3ß,6α,16ß,25- tetrahydroxy-20,24-epoxy-9,10-seco-cycloartan-9(11),10(19)-diene (1), (20R,24S)- 3ß,6α,16ß,25-tetrahydroxy-20,24-epoxy-9,10-seco-cycloartan-1(10),9(11)-diene (2), (20R,24S)-3ß,16ß,25-trihydroxy-6α,19α;20,24-diepoxy-9,10-seco-cycloartan-9(11)-ene (3), (20R,24S)-6α,16ß,25-trihydroxy-3ß,10ß;20,24-diepoxy-9,10-seco- cycloartan-11-one (4), (20R,24S)-16ß,25-dihydroxy-6α-methoxy-3ß,10ß;20,24- diepoxy-9,10-seco-cycloartan-7(8),9(11)-diene (5), (20R,24S)-6α,16ß,25-trihydroxy-3ß,10ß;20,24-diepoxy-9,10-seco-cycloartan-9(11)-ene (6), and (20R,24S)-3ß,6α,16ß,25-tetrahydroxy-19-acetoxy-ranunculan-9(10)-ene (7) by spectroscopic analysis. Among them, compounds 2 and 5 were new compounds. M. racemosus could catalyze ring expansion and epoxidation reactions to form 3ß,10ß-epoxy- or 6α,19α-epoxy-9,10-seco-cycloartane structures. These regio- and stereo-selective reactions are difficult to achieve by chemical means. In addition, the biological effects of isolated metabolites on increasing the lifespan of Caenorhabditis elegans were evaluated. Most of the metabolites could significantly extend the lifespan of C. elegans at 50 µM.

Acid hydrolysis of saponin-rich extracts of quinoa, lentil, fenugreek and soybean to yield sapogenin-rich extracts and other bioactive compounds.

BACKGROUND: Typical hydrolysis times of saponins generally do not take into consideration the effect of time on the degradation of the target compounds, namely sapogenins. When producing natural extracts, it should be borne in mind that conducting hydrolysis to yield a target compound might also affect the final composition of the extracts in terms of other bioactive compounds. In our study, saponin-rich extracts from fenugreek, quinoa, lentil, and soybean were produced and their acid hydrolysis to give sapogenin-rich extracts was conducted over different periods (0-6 h). The disappearance of saponins and appearance of sapogenins was analyzed using high-performance liquid chromatography-diode array detection-mass spectrometry (HPLC-DAD-MS) and gas chromatography-mass spectrometry (GC-MS), respectively. The impact of hydrolysis on the phytosterols and tocopherol in the extracts was also evaluated. RESULTS: Fenugreek showed the highest saponin content (169 g kg-1 ), followed by lentil (20 g kg-1 ), quinoa (15 g kg-1 ), and soybean (13 g kg-1 ). Hydrolysis for 1 h caused the complete disappearance of saponins and the greatest release of sapogenins. Hydrolyzed fenugreek and quinoa extracts contained the highest amounts of sapogenins and minor fractions of phytosterols and tocopherol. Hydrolyzed extracts of lentil and soybean contained a major fraction of phytosterols and a low fraction of sapogenins. In all cases, sapogenins decreased after 1 h of hydrolysis, phytosterols slightly decreased, and tocopherol was unaffected. Standards of diosgenin and oleanolic acid also showed this decreasing pattern under acid hydrolysis conditions. CONCLUSION: Hydrolysis times of 1 h for saponin-rich extracts from the assayed seeds guarantee the maximum transformation to sapogenin-rich extracts, along with phytosterols and tocopherol. Fenugreek and quinoa seeds are preferred for this. © 2018 Society of Chemical Industry.