Inhibitory effects of sea buckthorn extract on α-amylase and α-glucosidase: Mechanistic evaluation and interaction with acarbose and casein

This study investigated the inhibitory effects and mechanisms of sea buckthorn extract (SBE) on α -amylase and α -glucosidase and assessed the influences of acarbose and casein. Using enzyme inhibition assays, kinetics, fluorescence quenching, and molecular docking, SBE showed stronger inhibition of α -amylase (IC 50 88.9 ± 1.2 μg/mL) compared with acarbose (133.0 ± 2.1 μg/mL), but weaker inhibition of α -glucosidase (56.96 ± 0.208 μg/mL) compared with acarbose (0.06 ± 0.005 μg/mL). Kinetic analyses indicated mixed-type inhibition for both enzymes. Fluorescence data supported spontaneous complex formation with microenvironmental perturbation of chromophores and consequent intrinsic fluorescence quenching, consistent with reduced enzyme activity. Docking suggested stable interactions between SBE constituents and amino-acid residues of both enzymes. Combination assays showed additive effects with acarbose for α -amylase and synergism for α -glucosidase, while casein reversibly attenuated SBE’s inhibition. These findings support SBE as a natural digestive-enzyme inhibitor for functional foods and anti-diabetic formulations.