Furostanol saponins from Allium tuberosum

Three new furostanol saponins, tuberoside A, B and C, have been isolated from the seeds of Allium tuberosum. On the basis of chemical reactions and spectral data, their structures were established as 26-O-β-D-glucopyranosyl- (25 S)-5α-furost-20(22)-ene-2α,3β,26-triol 3-O-α-L-rhamnopyranosyl-(1→ 2)-O-β-D-glucopyranoside; 26-O-β-D-glucopyranosyl-(25 S)-5α-furost-20(22)- ene-2α,3β,26-triol 3-O-α-L-rhamnopyranosyl-(1 → 2)-[α-L-rhamnopyranosyl- (1 → 4)]-β-D-glucopyranoside and 26-O-β-D-glucopyranosyl-(25 S)-5α- furost-20(22)-ene-2α,3β,26-triol 3-O-α-L-rhamnopyranosyl-(1 → 2)-[β-D- glucopyranosyl-(1 → 3)]-β-D-glucopyranoside, respectively.