Five New Pregnane Glycosides from Gymnema sylvestre and Their α-Glucosidase and α-Amylase Inhibitory Activities

, a medicinal plant, has been used in Indian ayurvedic traditional medicine for the treatment of diabetes. Phytochemical investigation of led to the isolation of five new pregnane glycosides, gymsylosides A-E ( - ) and four known oleanane saponins, 3β- β-D-glucopyranosyl (1→6)-β-D-glucopyranosyl oleanolic acid 28- β-D-glucopyranosyl ester ( ), gymnemoside-W1 ( ), 3β- β-D-xylopyranosyl-(1→6)-β-D- glucopyranosyl-(1→6)-β-D-glucopyranosyl oleanolic acid 28- β-D-glucopyranosyl ester ( ), and alternoside XIX ( ). Their structures were identified based on spectroscopic evidence and comparison with those reported in the literature. All compounds were evaluated for their α-glucosidase and α-amylase inhibitory activities. Compounds - showed significant α-amylase inhibitory activity, with IC values ranging from 113.0 to 176.2 µM.