α-Glucosidase inhibitory activities of aromatic compounds from the rhizomes of Alpinia galanga

Inhibition of α-glucosidase is a widely recognized approach for managing hyperglycemia, particularly postprandial glucose spikes. In this study, the α-glucosidase inhibitory activity and interaction mechanisms of aromatic compounds isolated from the rhizomes of Alpinia galanga were investigated using the p-nitrophenol-α-D-glucopyranoside (pNPG) bioassay and molecular docking. The isolated aromatic compounds (1–4) showed significant α-glucosidase inhibitory activity with IC₅₀ values between 25 and 104 µM compared to the positive control acarbose (IC₅₀ = 1236.42 ± 1.30 µM). The experimental data showed that the most potent inhibitor of α-glucosidase (E)-p-coumaryl alcohol-γ-O-methyl ether (3) inhibited the enzyme via a mixed-type mechanism, with an IC₅₀ value of 25.00 ± 1.01 µM. Molecular docking indicated that compound 3 decreased the catalytic efficiency of α-glucosidase by competitively binding to the active pocket, thereby blocking the substrate. The binding activity is mainly mediated by hydrogen bonds and hydrophobic interactions. The results suggest that these aromatic compounds from A. galanga could serve as potential therapeutic agents for the control of postprandial hyperglycemia and the treatment of type 2 diabetes.