Steroidal saponins from Tribulus terrestris

Five new steroidal saponins were isolated from the fruits of Tribulus terrestris. Their structures were fully established by spectroscopic and chemical analysis as (23S,25S)-5 alpha-spirostane-24-one-3 beta,23-diol-3-O-{alpha-L-rhamnopyranosyl-(1 -> 2)-O-[beta-D-glucopyranosyl-(1 -> 4)]-beta-D-galactopyranoside} (1), (24S,25S)-5 alpha-spirostane-3 beta,24-diol-3-O-{alpha-L-rhamnopyranosyl-(1 -> 2)-O -[beta-D-glucopyranosyl-(1 -> 4)]-beta-D-galactopyranoside} (2), 26-O-beta-D-glucopyranosuyl-(25R)-5 alpha-furostan-2 alpha,3 beta,22 alpha,26-tetraol-3-O-{beta-D-glucopyranosyl-(1 -> 2)-O-beta-D-glucopyranosyl-(1 -> 4)-beta-D-galactopyranoside} (3), 26-O-beta-D-glucopyranosyl-(25R)-5 alpha-furostan-20(22)-en-2 alpha,3 beta,26-triol-3-O-{beta-D-glucopyranosyl-(1 -> 2)-O-beta-D-glucopyranosyl-(1 -> 4)-beta-D-galactopyranoside} (4), and 26-O-beta-D-glucopyranosyl-(25S)-5 alpha-furostan-12-one-22-methoxy-3 beta,26-diol-3-O-{alpha-L-rhamnopyranosyl-(1 -> 2)-O-[beta-D-glucopyranosyl-(1 -> 4)]-beta-D-galactopyranoside} (5). The isolated compounds were evaluated forcytostatic activity against HL-60 cells. (C) 2009 Published by Elsevier Inc.