Isolation and structure identification of steroidal saponin from Dioscorea zingiberensis / 中草药

ABSTRACT

Objective To study the chemical constituents of Dioscorea zingiberensis.Methods The fresh rhizome of D.zingiberensis was extracted three times,3 h once with EtOH-H2O at 80 ℃.The EtOH was evaporated under reduced pressure to give a residue which was suspended in water and then was exacted with petroleum ether,ethyl acetate,and n-butanol fraction.The water fraction was isolated by the reversed-phase ODS column chromatography.The chemical structures were elucidated by means of 1H-NMR,13C-NMR,135DEPT,HMQC,and HMBC spectroscopic analyses.Results Three steroidal saponins were isolated from the fresh rhizome of D.zingiberensis.The compounds were identified asdiosgenin-3-O-?-D-glucopyranosyl(1→3)-?-D-glucopyranosyl(1→4)-[?-L-rhamnopyranosyl(1→2)]-?-D-glucopyranoside(Ⅰ),(25R)-26-O-?-D-glucopyranosyl-furost-5-en-3?,22?-diol-3-O-?-D-glucopyranosyl(1→3)-?-D-glucopyranosyl(1→4)-[?-L-rhamnopyranosyl(1→2)]-?-D-glucopyranoside(Ⅱ),and(25R)-26-O-?-D-glucopyranosyl-furost-5-en-3?,22?-diol-7-carbonyl-3-O-?-D-glucopyranosyl(1→3)-?-D-glucopyranosyl(1→4)-[?-L-rhamnopyranosyl(1→2)]-?-D-glucopyranoside(Ⅲ).Conclusion Compound Ⅲ is a novel compound named as zingiberenin H.