Analysis of in vitro and in silico anti-hyperglycaemic action of bioflavonoids isolated from different citrus peels

Abstract

In this study, flavonoid-rich chloroform fraction (FRCF) of nine different citrus species was isolated by solvent fractionation technique and its effect on α-glucosidase, α-amylase, glucose uptake by yeast cells and glycosylation of haemoglobin was studied. FRCF of Citrus maxima was found to show higher activity in the in vitro assays and thus it was characterized by Electrospray Ionization Mass Spectrometry (ESI-MS) analysis. This led to the identification of icariin, hesperidin and diosmetin-6,8-di-C-glucoside. Their binding efficacy with targeted proteins such as glucokinase (GK), glycogen synthase kinases 3β (GSK 3β) and peroxisome proliferator-activated receptor-γ (PPAR-γ ) was studied by in silico analysis using Schrödinger Maestro software. Icariin exhibited maximum docking energy with GSK 3β, relatively less for GK and null for PPAR-γ. Hesperidin and diosmetin-6, 8-di-C-glucoside showed good binding affinity with PPAR-γ compared to GSK 3β.