Antidiabetic activity of (L.) Sweet leaves: and antidiabetic potential of isolated flavonoid glycosides and sulphated flavonoids.

Antidiabetic activity of methanolic extract, petroleum ether, ethyl acetate and -butanol fractions of (L.) Sweet leaves was performed using -glucosidase and -amylase inhibition methods. Phytochemical study of the ethyl acetate fraction which possessed the highest antidiabetic activity led to isolation of five flavonoids for the first time from this plant, including two rare flavonoid sulphates, ombuin-3-sulphate [] and rhamnetin-3-sulphate [] and three flavonoid glycosides, kaempferol 7---L-rhamnopyranoside [], kaempferol 3,7-di---L-rhamnopyranoside [] and quercetin 3---L-arabinopyranoside []. The H and C NMR of and C NMR of , were reported here for the first time. Compounds [-] showed a concentration-dependent inhibitory activity against glucosidase and amylase. Furthermore, study predicted that compounds (-) showed good interactions with glucosidase, amylase, and protein tyrosine phosphatase 1b.