In vitro and in silico studies on α-glucosidase inhibitory properties of bioactive components from the rhizomes of Alpinia officinarum Hance

Key digestive enzymes, α-glucosidase and α-amylase, are associated with the occurrence of type 2 diabetes mellitus (T2DM). Inhibition of these important enzymes is one of the important strategies for the treatment of T2DM. In the search for alternative α-glucosidase inhibitors, five compounds (1–5) were obtained from the rhizomes of Alpinia officinarum Hance by chromatographic methods. In vitro enzyme inhibition assays, kinetic analysis, and molecular docking studies were conducted to investigate the inhibition mechanism of the isolated compounds against α-glucosidase. Compounds 1, 3, 4, and 5 showed comparable α-glucosidase inhibitory activities to quercetin (IC₅₀ value of 19.77 µM) with IC₅₀ values ranging from 37.48 to 89.08 µM. According to the findings of the kinetic analysis, compounds 1, 2, and 4 were uncompetitive inhibitors, while compound 3 was a competitive inhibitor and compound 5 was a mixed-type inhibitor of α-glucosidase. In the computational investigation, hydrogen bonds served as the primary bond between the compounds and the amino acid residues. The results showed that A. officinarum might be a viable source of α-glucosidase inhibitors and antidiabetic agents.