C21 Steroidal Glycosides from Acidic Hydrolysate of Cynanchum otophyllum

ObjectiveTo investigate the structures of compounds in the rhizome of Cynanchum otophyllum (Asclepiadaceae), and to find new C21 steroidal glycosides.MethodsThe ethyl acetate extract from the rhizome was subjected to acidic hydrolysis and isolated by column chromatography; The structures of the purified compounds were determined by spectral methods. Literature search confirmed whether those compounds were of new structures.ResultsThree compounds were isolated and their structures were deacetylmetaplexigenin 3-O-β-D-oleandropyranosyl-(1→4)-α-D-oleandropyranosyl-(1→4)-α-D-oleandropyranoside (1), deacetylmetaplexigenin 3-O-α-D-oleandropyranosyl-(1→4)-β-D-thevetopyranosyl-(1→4)-α-D-oleandropyranoside (2), and deacetylmetaplexigenin 3-O-β-D-cymaropyranosyl-(1→4)-α-D-oleandropyranoside (3), respectively.ConclusionCompounds 1–3 are new compounds.