New Pregnane Glycosides from Gymnema sylvestre

Abstract

Four new pregnane glycosides 1-4 were isolated from the ethanol extract of the stem of Gymnema sylvestre and named gymsylvestrosides A-D. Hydrolysis of compound 1 under the catalysis of Aspergilus niger β-glucosidase afforded compound 5 (gymsylvestroside E). Their structures were determined by spectroscopic methods such as HRESIMS, 1D and 2D NMR, as well as HMQC-TOCSY experiment. Compounds 1-4 were screened for Saccharomyces cerevisiae α-glucosidase inhibitory activity.