Inhibition Mechanism of Berberine on α-Amylase and α-Glucosidase in Vitro

Berberine is separated from medical plants and food raw materials, and shows excellent anti-diabetic activity and could be used as a food additive in some countries and regions. However, its inhibitory mechanisms on alpha-amylase and alpha-glucosidase have hardly ever been revealed in vitro. In this study, enzymatic reaction kinetics, fluorescence quenching, circular dichroism spectroscopy, and molecular docking are used to study the inhibitory effects of berberine on alpha-amylase and alpha-glucosidase. Berberine has great inhibitory effects on alpha-amylase and alpha-glucosidase (IC50 = 50.83 mu g mL(-1), IC50 = 198.4 mu g mL(-1). respectively), and inhibition types of alpha-amylase and alpha-glucosidase are non-competitive inhibition and competitive inhibition, respectively. Fluorescence spectra show that there is static quenching between berberine and alpha-amylase or alpha-glucosidase. Besides, hydrophobic interaction is the main interaction type. These results are further evidenced and visualized by molecular docking. This study provides a different theoretical basis for berberine in anti-diabetic activity in vitro and expands interaction research about hydrophobic compounds and alpha-amylase as well as alpha-glucosidase.