Pueraria lobata root constituents as xanthine oxidase inhibitors and protective agents against oxidative stress induced in ges-1 cells

Abstract

Ultrafiltration coupled with liquid chromatography-mass spectrometry (LC-MS) was established to screen xanthine oxidase (XO) inhibitors from Pueraria lobata root extract. Four compounds were screened out and identified as puerarin, daidzin, daidzein and genistein with half-maximal inhibitory concentration (IC50) values of 30.8, 5.31, 14.5 and 3.02 μg mL−1 on XO, respectively. The interactions between these compounds and XO were investigated by fluorescence spectroscopic method. The hydrogen peroxide induced oxidative stress model of human normal gastric epithelial cell lines (GES-1) was used to investigate the protections on injured cell. As a result, four XO inhibitors exhibited protective effects without cytotoxicity. With the increased concentrations of four inhibitors, cell viability was higher with decreased mortality rate, the decrease of superoxide dismutase activity, leakage of lactate dehydrogenase and increase of intracellular superoxide anion production induced by hydrogen peroxide were restrained. It showed that these four XO inhibitors could effectively enhance cell viability and protect injury of GES-1 cells from oxidative stress.