Steroidal saponins from fruits of Tribulus terrestris

Abstract

Further studies on the constituents of the fruits of Tribulus terrestris led to the isolation of six new furostanol saponins, 26-O-β-D-glucopyranosyl (25R)-furostane-2α,3β,22α,26-tetrol-3-O-β-D-glucopyranosyl (1-4)-β-D- galactopyranoside, 26-O-β-D-glucopyranosyl (25R,S)-5α-furostane- 2α,3β,22α,26-tetrol-3-O-β-D-galactopyranosyl(1-2)-β-D-glucopyranosyl(1- 4)-β-D-galactopyranoside, 26-O-β-D-glucopyranosyl (25R,S)-5α-furostane- 3β,22α,26-triol-3-O-β-D-galactopyranosyl(1-2)-β-D-glucopyranosyl(1-4)- β-D-galactopyranoside, 26-O-β-D-glucopyranosyl (25R,S)-5α-furostan-12- one-3β,22α,26-triol-3-O-β-D-galactopyranosyl(1-2)-β-D-glucopyranosyl(1- 4)-β-D-galactopyranoside, 26-O-β-D-glucopyranosyl (25R,S)-furost-5-ene- 3β,22α,26-triol-3-O-β-D-galactopyranosyl(1-2)-β-D-glucopyranosyl(1-4)- β-D-galactopyranoside, 26-O-β-D-glucopyranosyl (25R)-5α-furost-20(22)-en- 12-one-3β,26-diol-3-O-β-D-galactopyranosyl(1-2)-β-D-glucopyranosyl(1-4)- β-D-galactopyranoside, named terrestrosin F-K, respectively. The structures were elucidated on the basis of spectroscopic studies of the isolated compounds and their hydrolysed products.