Mechanistic investigation of anthocyanidin derivatives as α-glucosidase inhibitors.

Eight anthocyanidin derivatives (1-8) were evaluated as potential inhibitors of the catalysis of α-glucosidase. Among them, compounds 4 and 8 had the highest levels of inhibitory activity at 100 μM (IC50 values of 14.4 ± 0.1 and 29.7 ± 1.2 μM) and acted in a dose-dependent manner. Enzyme kinetic analysis further revealed that these inhibitors interacted with α-glucosidase in a mixed noncompetitive mode. Moreover, fluorescence quenching studies provided parameters for calculating the binding mechanism between receptor and ligand. On the basis of these studies, and in silico simulations, we determined that the ligand was likely docked in the receptor. Thus, compounds 4 and 8 are excellent potential targets for in vitro cell-based and in vivo assays related to treatment of diabetes.