Epicatechin and quercetin exhibit in vitro antioxidant effect, improve biochemical parameters related to metabolic syndrome, and decrease cellular genotoxicity in humans

Abstract Metabolic syndrome is a condition whose incidence has been increasing around the world. It promotes a metabolic state of chronic systemic inflammation, correlated to cellular stress and genetic mutations, and subsequently with deadly chronic diseases, such as type 2 diabetes mellitus, cardiovascular diseases, and cancer. A randomized placebo-controlled study (n = 156) was conducted to determine the effects of consuming an enriched bread with 0.05% of a 1:1 mixture of (−)-epicatechin and quercetin on anthropometric and biochemical parameters of the participants. As a result, total cholesterol, LDL-cholesterol, total triglycerides, and fasting plasma glucose significantly decreased after three months of daily enriched bread consumption. Nuclear abnormalities in buccal epithelium cells also decreased (15.8 ± 3.2 down to 8.3 ± 1.0), showing a genoprotective effect. The antioxidant properties of these compounds were observed by monitoring changes in the cytoplasmic redox tone of intact Caco-2 cells expressing HyPer, a fluorescent redox biosensor. The combination of (–)-epicatechin and quercetin changes the cytoplasmic redox ambient in living cells and significantly improves biochemical parameters related to metabolic syndrome, and decreases the number of cell abnormalities in buccal epithelium cells of patients.