Terrestrinins A and B, two new steroid saponins from Tribulus terrestris.

Two new steroid saponins, named terrestrinins A (1) and B (2), along with six known compounds were isolated from the Chinese medicine herb Tribulus terrestris, and their chemical structures were elucidated as 26-O-beta-D-glucopyranosyl-(25S)-furostan-4(5),20(22)-diene-3,12-dione (1) and 26-O-beta-D-glucopyranosyl-(25S)-5alpha-furostane-3beta,22alpha,26-triol-3-O-beta-D-xylopyranosyl(1 --> 3)-[(beta-D-xylopyranosyl(1 --> 2)]-beta-D-glucopyranosyl(1 --> 4)-[alpha-L-rhamnopyranosyl(1 --> 2)]-beta-D-galactopyranoside (2) on the basis of spectroscopic techniques.