Concentration‐dependent effect of (−) epicatechin in hypertensive patients

Non‐vitamin polyphenolic compounds are ubiquitous in food plants and therefore potentially present in human plasma in a diet‐dependent concentration. The aim of this study was to evaluate the concentration‐dependent effect of (?) epicatechin, a polyphenol present in green tea with antioxidant activity, on various biomarkers of oxidative stress. The current study examined the in vitro concentration‐dependent (10^?4 M to 10^?7 M) effects of (?) epicatechin on biomarkers of oxidative stress viz. malondialdehyde (MDA), reduced glutathione (GSH), membrane sulfhydryl (‐SH) group and protein carbonyl content in hypertensive patients and normal ones. This effect seems to be due to ability of (?) epicatechin to reduce MDA and protein carbonyl content while increase in GSH and membrane ‐SH group in hypertensive patients. It can be concluded that (‐) epicatechin exerts an antioxidant action inside the cell, responsible for the observed modulation of cellular response to oxidative challenges. Copyright © 2010 John Wiley & Sons, Ltd.