Preparative isolation and purification of five steroid saponins from Dioscorea zingiberensis C.H.Wright by high-speed counter-current chromatography coupled with evaporative light scattering detector

摘要

A high-speed counter current chromatography (HSCCC) method was successfully applied to separate and purify steroid saponins from the traditional Chinese medicine Dioscorea zingiberensis C.H.Wright for the first time. Ethyl cetate-n-butanol-methanol-water (4:1:2:4, v/v) was used as the two-phase solvent system, and evaporative light scattering detector (ELSD) was used as the detector in this method. The method separated in a single run the following five steroid saponins: 26-O-β-D-glucopyranosyl-(25R)-furost- 5-en-3β,22ζ,26-triol-3- O-[β-D-glucopyranosyl-(1→3)-β-D-glucopyranol- (1→4)-α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (>Compound A); 26-O-β-D-glucopyranosyl-(25R)-furost-5-en-3β,22ζ,26- triol-3-O-[β-D-glucopyranosyl (1→3)-α-L-rhamnopyranosyl(1→2)]-β-D-glucopyranoside (>Compound B); 26-O-β-D-glucopyranosyl-(25R)-furost-5-en-3β, 22ζ, 26-triol- 3-O- [α-L-rhamnopyranosyl (1→4)]-β-D-glucopyranoside (>Compound C); 26- O-β-D- glucopyranosyl- (25R)- furost-5, 20(22)-diene-3β, 26-diol-3-O-{α-L-rhamnopyranosyl- (1→4)-[β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl-(1→2)]}-β-D-glucopyranoside (>Compound D); and 26-O-β-D-glucopyranosyl-(25R)-furost-5, 20(22)-diene-3β, 26-diol-3 -O-[β-D-glucopyranosyl- (1→4)-α-L-rhamnopyranosyl(1→2)]-β-D-glucopyranoside (>Compound E). Their structural identification of the five steroid saponins was performed by means of ESI-MS, and ¹³C NMR.