ABSTRACT
Objective:To investigated the activity inhibition and inhibitory type of polyphenol oxidase (PPO) induced by galangin and the interaction mechanism of galangin with polyphenol oxidase was preliminarily indicated,and prove the related mechanism of galangin on proliferation of on human melanoma A375 cells.Methods: The activity inhibition and inhibitory type of PPO induced by galangin were investigated by spectrophotometric method,and interation mechanism of galangin with PPO was preliminarily indicated by fluorescence quenching and molecular docking,and chelating copper ions with the inhibitory mechanism of galangin on polyphenol oxidase was measured.Results: Galangin was a competitive inhibitor,the IC50 and Ki on PPO were obtained to be (47.86±3.33) and (24.83±1.45)μmol/L,respectively.Fluorescence spectrum indicated the fluorescence of PPO was quenched effectively by galangin and the binding constant Ka was obtained to be (4.67±0.43)×104 L/mol.Chelating copper ions and molecular simulation further showed that galangin was combined with active center of copper ions,and formed hydrogen bonds with catalytic site His259.Luteolin could induce the apoptosis of A375 cells significantly,and the tyrosinase activity and melanin synthesis were decreased.Conclusion: Galangin as a competitive polyphenol oxidase inhibitor and reduced the activity of polyphenol oxidase.which provides the theoretical basis for the clinical anti skin cancer.