α-Glucosidase inhibition by flavonoids: an in vitro and in silico structure-activity relationship study

alpha-Glucosidase inhibitors are described as the most effective in reducing post-prandial hyperglycaemia ( PPHG) from all available anti-diabetic drugs used in the management of type 2 diabetes mellitus. As flavonoids are promising modulators of this enzyme's activity, a panel of 44 flavonoids, organised in five groups, was screened for their inhibitory activity of alpha-glucosidase, based on in vitro structure-activity relationship studies. Inhibitory kinetic analysis and molecular docking calculations were also applied for selected compounds. A flavonoid with two catechol groups in A-and B-rings, together with a 3-OH group at C-ring, was the most active, presenting an IC50 much lower than the one found for the most widely prescribed alpha-glucosidase inhibitor, acarbose. The present work suggests that several of the studied flavonoids have the potential to be used as alternatives for the regulation of PPHG.