Oleanane saponins from Gymnema sylvestre.

Abstract 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.