Four new pregnane glycosides from Gymnema latifolium and their alpha-glucosidase and alpha-amylase inhibitory activities

Abstract

Four new pregnane glycosides, gymlatifosides A - D (1 - 4) and one known pregnane glycoside, verticilloside J (5) were isolated from the leaves of Gymnema latifolium Wall. ex Wight. Their chemical structures were elucidated on the basis of extensive spectroscopic methods, including 1D, 2D NMR, HR-ESI-MS, and in comparison with the reported data. All these compounds were tested for alpha-glucosidase and alpha-amylase inhibitory activities. Compound 5 exhibited the most anti alpha-glucosidase activity with inhibitory percentage of 37.8 +/- 1.5% at the concentration of 200 mu M. Compounds 1-4 showed moderate anti alpha-glucosidase activity with inhibitory percentage ranging from 7.0 to 30.1%. In addition, all compounds 1-5 showed moderate/weak anti alpha-amylase activity in the investigated test. [GRAPHICS] .