Ypsiyunnosides A-E, Five New Cholestanol Glycosides from Ypsilandra yunnanensis

Phytochemical investigation on the whole plants of Ypsilandra yunnanensis was carried out for the first time and led to the isolation of five new cholestanol glycosides, ypsiyunnosides A-E (1-5), and one known analogue. Their structures were determined mainly by detailed spectroscopic analysis, including extensive 1D and 2D NMR, MS and UV, as well as chemical methods. Among them, compound 1 possessed a rare 6/6/6/5/5 fused-rings cholestanol sketelon, which was identified as (23R,25R)-3β,16α,26-triol-16,23-cyclocholest-5,17(20)-dien-22-one. Their induced platelet aggregation activities and cytotoxicities were evaluated. Five new cholestanol glycosides, ypsiyunnosides A-E (1-5), were isolated from the whole plants of Ypsilandra yunnanensis. Compound 1 possessed a rare 6/6/6/5/5 fused-rings cholestanol sketelon. Their structures were elucidated by a combination of 1D and 2D NMR, MS and chemical analysis.