Oleanane saponins from Gymnema sylvestre

Six oleanane-type saponins, along with two known triterpene saponins, were isolated from the leaves of Gymnema sylvestre. The structures of the oleanane triterpene glycosides were characterized as longispinogenin 3- O-β- D-glucuronopyranoside, 21β-benzoylsitakisogenin 3- O-β- D-glucuronopyranoside, 3- O-β- D-glucopyranosyl(1→6)-β- D-glucopyranosyl oleanolic acid 28- O-β- D-glucopyranosyl ester, oleanolic acid 3- O-β- D-xylopyranosyl(1→6)-β- D-glucopyranosyl(1→6)-β- D-glucopyranoside, 3- O-β- D-xylopyranosyl(1→6)-β- D-glucopyranosyl(1→6)-β- D-glucopyranosyl oleanolic acid 28- O-β- D-glucopyranosyl ester and 3- O-β- D-glucopyranosyl(1→6)-β- D-glucopyranosyl oleanolic acid 28-β- D-glucopyranosyl(1→6)-β- D-glucopyranosyl ester on the basis of hydrolysis and spectral evidence, including 1D- and 2D-NMR (TOCSY, ROESY, HMQC and HMBC) and FABMS analyses.