Following the characterization of gymnemosides-a and -b, new triterpene glycosides, gymnemosides-c, -d, -e, and -f, were isolated from the leaves of Gymnema (G.) sylvestre R. BR. Their chemical structures were elucidated an the basis of chemical and physicochemical evidence as follows: 21-O-benzoyl-28-O-acetylgymnemagenin 3-O-β-D-glucopyranosiduronic acid (gymnemoside-c), 23-O-[β-D-xylopyranosyl(1→6)-β-D-glucopyranosyl(1→6)-β-D-glucopyranosyl]gymnestrogenin(gymnemoside-d), 23-O-[β-D-xylopyranosyl)1→6)-β-D-glucopyranosyl(1→6)-β-D-glucopyranosyl]-28-O-[β-D-glucopyranosyl(1→6)-β-D-glucopyranosyl] 23-hydroxylongispinogenin (gymnemoside-e), 23-O-[β-D-glucopyranosyl(1→6)-β-D-glucopyranosyl(1→6)-β-D-glucopyranosyl]-28-O-[β-D-glucopyranosyl(1→6)-β-D-glucopyranosyl] 3β,16β,23,28-tetrahydroxyolean-18-ene (gymnemoside-f). The inhibitory effects of gymnemosides-c, -d, -e, and -f and principal triterpene glycosides from G. sylvestre on glucose uptake in rat small intestinal fragments were examined, and gymnemic acids II, III, and IV, gymnemasaponin V, and gymnemoside-f were found to exhibit the inhibitory activity.
medicinal foodstuff, gymnemosid, Gymnema sylvestre, glucose uptake inhibitor, bioactive saponin, gymnemic acid
NCBI PubMed ID: 9433774Journal NLM ID: 0377775Publisher: Pharmaceutical Society Of Japan
Institutions: Kyoto Pharmaceutical University, Kyoto, Japan
Methods: 13C NMR, 1H NMR, IR, FAB-MS, sugar analysis, acid hydrolysis, GLC, methanolysis, HPLC, alkaline hydrolysis
Found