α-glucosidase inhibitors (AGIs) are widely used for the treatment of type 2 diabetes, but their side effects have made it to develop novel and alternative AGIs immediately. In this study, the extract of Hypericum perforatum L. (HPE) has been confirmed to have α-glucosidase inhibitory activity in vitro and in vivo. Seven active compounds, rutin, hyperoside, isoquercitrin, avicularin, quercitrin, quercetin, and biapigenin, were screened based on a bio-affinity chromatography column with α-glucosidase enzyme-conjugated solid phase and UPLC/MS, which exhibited excellent α-glycosidase inhibitory effects by the determined IC50 values. The mechanism of α-glycosidase inhibitory activity of biapigenin was studied for the first time. The results showed that biapigenin was a high-potential, reversible, and mixed enzyme inhibitor. Analysis by molecular docking further revealed that hydrophobic interactions were generated by interactions between biapigenin and amino acid residues LYS156, PHE303, PHE314, and LEU313. In addition, hydrogen bonding occurred between biapigenin and α-glucosidase amino acid residues ASP307, SER241, and LYS156. This research identified that biapigenin could be a novel AGI and further applied to the development of potential anti-diabetic drugs. Furthermore, our studies established a rapid in vitro screening method for AGIs from plants.
Keywords: Hypericum perforatum L; UPLC/MS; alpha-glucosidase inhibitors; bio-affinity chromatographic column; molecular docking.
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