Study On The Inhibitory Mechanism Of Piceatannol On ?-glucosidase And UGTs

Piceatannol?PIC?is,a natural polyphenolic compound,abundant in passion fruit and blueberries.It has wide spectrum of biological activity,which can improve metabolic disorders such as hyperglycemia and insulin resistance.The anti-diabetic activity of piceatannol may be related to the inhibition of?-glucosidase,but the mechanism of its interaction is not yet clear.Therefore,the study mainly uses experimental methods such as enzyme kinetics,thermodynamics and molecular docking simulation to study the inhibitory effect of piceatannol on?-glucosidase and explore its inhibition mechanism.Enzyme kinetics analysis showed that piceatannol exhibited strong inhibition on?-glucosidase in a non-competitive manner,which half inhibitory concentration(IC₅₀)and half inhibitory constant?K_i?were 4.39±0.74?M and5.38±0.24?M,respectively.Spectroscopy analysis indicated that piceatannol can quench the endogenous fluorescence of?-glucosidase in a dose-dependent manner and form a high-affinity complex with?-glucosidase.In addition,molecular docking study validated that the binding of piceatannol was outside the catalytic site of?-glucosidase,which would induce the conformational changes of?-glucosidase and block the entrance of substrates,causing declines in?-glucosidase activity.These results indicate that piceatannol can decline the activity of?-glucosidase,which can be used as a potential treatment of diabetes drugs or dietary supplements for diabetic patients.Evaluation of drug-like properties is of great significance to improve the success rate of drug discovery and development.Therefore,on the basis of our investigation of the good efficacy of piceatannol,we conducted a preliminary evaluation of its drug-like properties by evaluating the effect of piceatannol on human metabolic enzyme activity.The effect of piceatannol on the activity of cytochrome P450?CYPs?has been reported.However,whether piceatannol affects the activity of human UDP-glucuronosyltransferase?UGTs?remains unclear.The study further evaluated the potential inhibitory of piceatannol against UGTs,as well as to evaluate the potential drug-drug interaction via UGTs inhibition.We systematically evaluated the inhibitory effects of piceatannol on UGTs using high-performance liquid chromatography system by measuring the formation rate for 4-methylumbelliferone glucuronic acid and imipramine N-glucuronic acid.The results indicated that piceatannol displayed broad-spectrum inhibition against human UGTs.Kinetic analysis showed that inhibition of piceatannol on UGT1A6 and UGT1A7 followed noncompetitive inhibition mechanism,while the inhibition on UGT1A8 and UGT1A9 obeyed either competitive and mixed inhibition mechanism,respectively.The quantitative prediction of risks showed that the coadministration of 2 passion fruit or 20 mg of piceatannol with drugs primarily cleared by UGT1A6,UGT1A7,UGT1A8,and UGT1A9 may result in potential drug-drug interaction.Therefore,when developing and applying piceatannol as a potential inhibitor of?-glucosidase,special attention should be paid to the risk of interaction between piceatannol and UGTs enzyme-mediated substrates in vivo.