Grape polyphenols have shown beneficial effects in a number of in vitro and in vivo biological studies. The availability and the activities of anthocyanins, quercetin, resveratrol, catechins, proanthocyanidines, caffeic acid, gallic acid, and tyrosol are summarized. The antioxidant effects, and the mechanisms of prevention of atherosclerosis, cardiovascular disease, cancer, dementia and other diseases are described. Most grape polyphenols have shown their biological activities at the low concentrations obtained with the dietary intake. Short-term clinical investigations have shown beneficial effects on risk markers and intermediate events. Long-term prospective studies on the incidence of disease or on the life expectancy are needed. Grape-derived nutraceutical are polyphenol-rich supplements placed on the borderline between drugs and foods. They have safety issues due to the potential toxicity of phenol excessive intake. Controlled clinical trials should be performed for an appropriate evidence of their health benefits.
Keywords: anthocyanines, quercetin, resveratrol, catechines, proanthocyanidines, caffeic acid, gallic acid, tyrosol