Identification and Isolation of Steroidal Saponins of Dioscorea zingiberensis Wright

Two diosgenin trisaccharides (A,B) and two furostanolic tetrasacharides of diosgenin (C, D) had been isolated from Dioscorea zingiberensis wright. By means of acetylation, acid hydrolysis, enzymolysis, IR, MS, 1H-NMR and 13C-NMR, saponin A was proved to be a new compound of structure: diosgenin-3-O- [ β-D-glucopyranosyl (1 → 2) ]-O- [ α-L-rhamnopyra- nosyl (1→3)]-O-β-D-glucopyranoside was provisionally named zingiberenin A; saponin B may be suggested as the steric isomer of gracillin; saponin C was identified as 26-O-β-D- glucopyranoside of A and saponin D as 26-O-β-D-glucopyranoside of B. The last two components named proto-zingiberenin A and proto-zingiberenin B respectively.