Evaluation of α-glucosidase inhibition potential of some flavonoids fromEpimedium brevicornum

Abstract

Epimedium brevicornum leaves water extract exerted a potent and specific inhibition against yeast α-glucosidase, with 50% inhibition of activity (IC50) at 11.8μmol/L (or 2.01μg) Gallic Acid Equivalent (GAE)/mL. Several major flavonols from the leaves were evaluated for inhibitory activity. Baohuoside I exhibited strong inhibition against the α-glucosidase while icariin and epimedin A, B and C were weak or inactive. All compounds were inactive against pancreatic α-amylase. The IC50 of baohuoside I was 28.9μmol/L and its kinetic mode of inhibition was of the mixed type inhibition, with K1 (inhibition constant for the formation of the baohuoside-enzyme complex) and K2 (inhibition constant for t..