Abstract
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.