AIM: To study the chemical constituents of stems of Gymnema sylvestre (Retz.) Schult. METHODS: Chromatographic techniques using silica gel, C18 reversed phase silica gel, and prep-HPLC were used. The structures were elucidated on the basis of MS and spectroscopic analysis (1D and 2D NMR), as well as chemical methods. RESULTS: Seven compounds were isolated and their structures were elucidated as conduritol A (1), stigmasterol (2), lupeol (3), stigmasterol-3-O-β-D-glucoside (4), the sodium salt of 22α-hydroxy-longispinogenin-3-O-β-D-glucopyranosyl-(1→3)-β-D-glu-curono-pyranosyl-28-O-α-L-rhamnopyranoside (5), oleanolic acid-3-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (6), and the sodium salt of 22α-hydroxy-longispinogenin 3-O-β-D-glucuronopyranosyl-28-O-α-L-rhamnopyranoside (7). The inhibition activities of compounds 1, 5-7 on non-enzymatic glycation of protein in vitro were evaluated. CONCLUSION Compound 7 is a new triterpenoid saponin. It was shown that compounds 1, 5-7 have weak inhibition activities for non-enzymatic glycation of protein in vitro.
Drugs, Chinese Herbal ; chemistry ; isolation & purification ; Gymnema sylvestre ; chemistry ; Molecular Structure ; Plant Stems ; chemistry

OBJECTIVETo investigates the mechanism of hypooglycemic effect of conduritol A of stems of Gymnema sylvestre.

METHODFourteen days later after administration, observation is taken on the change of these mice and rats weight, the FBG, TG, CHO, SOD, MDA, INS, TNF in serum were also detected with enzymology method and Radioimmuoassay method. Take the liver to determine the disposal of glucose. Take the pancreas to do the HE and immunohistochemistrial staining, and show pancreas islet beta-cell. Calulate thymus, pancreas, splenica index.

RESULTCompared with diabetic model mice, high and middosage of conduritol A could remarkably reduce fasted blood sugar in diabetic rats induced by alloxan (P < 0.01). Significantly increase the level of serum insulin (P < 0.05). Activity of SOD was obviously increased, and amount of MDA was obviously decreased (P < 0.05). The amount of conduritol A disposal of glucose was obviously increased (P < 0.05). Significantly increase thymus, pancreas, splencia index (P < 0.01 or 0.05); inhibited the atrophy of thymus, pancreas, splencias of the diabetic rats induced by alloxan. Compared with diabetic model group, cell structure and form of conduritol A had been some way improved. The immunohistochemistry results showed that beta-cells numbers of pancreas in each conduritol A group were more than those in the model group.

CONCLUSIONConduritol A could have an effect on regulating the metabolism of blood lipid, free-radical scavenging, enhancing the antioxidant ability, potentiating immune function. Promoting synthesis of hepatic to decrease fasted blood suger.

Animals ; Blood Glucose ; drug effects ; Diabetes Mellitus ; drug therapy ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Female ; Gymnema sylvestre ; chemistry ; Humans ; Hypoglycemic Agents ; pharmacology ; Male ; Models, Animal ; Random Allocation ; Rats ; Rats, Wistar

OBJECTIVEConsuming botanical dietary supplements or herbal drugs along with prescription drugs may lead to potential pharmacokinetic-pharmacodynamic (PK-PD) herb-drug interactions (HDI). The present study focuses on the importance of and novel approach for assessing HDI in integrative medicine with case examples of two frequently-used Ayurvedic Rasayana botanicals.

METHODSThe aqueous extracts of Asparagus racemosus (ARE) and Gymnema sylvester (GSE) were prepared as per Ayurvedic Pharmacopoeia of India. Chemoprofiling of these extracts was done using high-performance liquid chromatography (HPLC). Additionally, ARE was characterized for the presence of shatavarins IV and I using HPLC & mass spectroscopy respectively. Effects of ARE and GSE were investigated on rat liver microsome using testosterone probe drug assay. The changes in formation of metabolite (6-β hydroxy testosterone) were monitored on incubation of testosterone alone, testosterone with ketoconazole, ARE and GSE using HPLC. Half inhibitory concentration (IC50) was used to predict plausible HDI.

RESULTSARE and GSE showed no inhibition with IC50 values >1 000 μg/mL while the standard inhibitor ketoconazole completely abolished CYP3A4-dependent activity at 0.531 μg/mL and IC50 was found to be 0.036 μg/mL.

CONCLUSIONARE and GSE prepared as per Ayurvedic Pharmacopoeia of India were found to be safe for CYP3A4-mediated inhibitory HDI in rats. Our in vitro study suggests the need of further in vivo investigation for HDI in order to provide clinical relevance.

Animals ; Asparagus Plant ; Chromatography, High Pressure Liquid ; Cytochrome P-450 CYP3A ; metabolism ; Cytochrome P-450 CYP3A Inhibitors ; pharmacology ; Gymnema sylvestre ; Herb-Drug Interactions ; Isoenzymes ; antagonists & inhibitors ; Plant Extracts ; pharmacology ; Rats ; Rats, Wistar