Polyphenols: A promising nutritional strategy for the prevention and treatment of hypertension

Hypertension is the leading risk factor for cardiovascular diseases worldwide. Long-term hypertension causes vascular endothelial dysfunction mainly through reduced nitric oxide (NO) bioavailability, impaired endothelium-dependent hyperpolarization (EDH), and increased production of endothelium-derived contracting factors, the consequences of which lead to cardiovascular diseases. However, less than 30% of hypertensive subjects worldwide have their blood pressure controlled at below 140/90 mmHg. It is thus of great importance to find a promising strategy to prevent and treat hypertension as well as hypertension-associated endothelial dysfunction. Polyphenols are secondary metabolites of plants abundantly found in fruits, vegetables, tea, coffee, wine, etc. Accumulating clinical evidence suggests that polyphenols, including anthocyanins, genistein, quercetin, and resveratrol, as well as polyphenol-rich foods lower blood pressure, augment endothelium-dependent blood flow, and reduce the risk of cardiovascular diseases. Moreover, preclinical studies, including animal models of hypertension revealed that polyphenols and polyphenol-rich foods exert beneficial effects on endothelial function mainly through the increased bioavailability of NO and/or EDH with accompanying decrease in blood pressure. In this review, we attempt to summarize the accumulating evidence supporting the beneficial effects of polyphenols and polyphenol-rich foods on blood pressure and endothelial function both in humans and in animals and to explore the underlying mechanisms.