Inhibitory Effect of Phellodendrine on α-Glucosidasein vitro

OBJECTIVE To study the inhibitory effect and the inhibition type of phellodendrine on α-glucosidasein vitro and explore the molecular mechanism. METHODS An inhibitor screening model was establishedin vitro to examine the inhibitory rate of phellodendrine on α-glucosidase.The inhibition type was investigated by kinetic method. The three-dimensional structure of α-glucosidase （Saccharomyces cerevisiae） was constructed by homology modeling method， and the inhibition molecular mechanism of phellodendrine on α-glucosidase was analyzed by molecular docking technology. RESULTS Phellodendrine displayed obvious inhibitory activity on α-glucosidase with an IC₅₀ value of 126.36 mg/L， in a concentration-dependent manner. The results of enzyme kinetics indicated that the reaction rate was lowered and V_max， K_m were decreased with the concentration increasing of phellodendrine. The results of molecular docking showed that the binding energy of phellodendrine to α-glucosidase site 5 was the lowest， and its optimal docking conformation binding energy was -31.4 kJ/mol. Phellodendrine exerted its inhibitory activity by forming hydrogen bonds with amino acid residues such as LYS15， SER295， HIS258， hydrophobic interaction with ALA289 and π-anion interaction with GLU10. CONCLUSION Phellodendrine is a reversible uncompetitive inhibitor of α-glucosidase. The hydrogen bond， hydrophobic interaction and π-anion interaction are main forces between phellodendrine and α-glucosidase.