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 oleana ne triterpene glycosides were characterized as longispinogenin 3-O-beta-D-g lucuronopyranoside, 21 beta-benzoylsitakisogenin 3-O-beta-D-glucuronopylano syl, 3-O-beta-D-glucopyanosyl(1-->6)-beta-D-glucopyranosyl oleanolic acid 2 8-O-beta-D-glucopy ranosyl ester, oleanolic acid 3-O-beta-D-xylopyranosyl(1 -->6)-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranoside, 3-O-beta-D-xylop yranosyl(1-->6)-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl oleanoli c acid 18-O-beta-D-glucopyranosyl ester and 3-O-beta-D-glucopymnosyl(1-->6) -beta-D-glucopyranosyl oleonolic acid 28-beta-D-glucopyranosyl(1-->6)-beta- D-glucopyranosyl ester on the basis of hydrolysis and spectral evidence, in cluding 1D- and 2D-NMR (TOCSY, ROESY, HMQC and HMBC) and FABMS analyses. (C ) 2000 Elsevier Science Ltd. All rights reserved.