The blood pressure lowering effect of a fruit and vegetable-rich diet is a necessary dietary lifestyle measure now included the guidelines for the management of arterial
hypertension. Furthermore,
flavonoids represent a major class of plant polyphenolics. The present review addresses the
antihypertensive effect of
quercetin, one of the most abundant
flavonoids present in fruits and vegetables, and probably the best studied
flavonoid because of its high biological activity.
Quercetin has been shown to induce a progressive, dose-dependent and sustained reduction in blood pressure when given chronically in several rat models of
hypertension, including spontaneously hypertensive rats,
L-NAME-treated rats,
DOCA-
salt hypertensive rats, two-kidney one-
clip Goldblatt rats, rats with aortic constriction and Dahl
salt-sensitive hypertensive rats.
Quercetin was also effective in reducing blood pressure in rat models of
metabolic syndrome, including the obese Zucker rats as well as rats treated with a high-
sucrose, high-fat diet.
Quercetin also prevented morphological and functional changes in the heart, vessels and kidney, while increasing production of
reactive oxygen species associated with
hypertension. A high dose of
quercetin also reduced blood pressure in stage 1 hypertensive patients in a randomized, double-blind, placebo-controlled, crossover study. Since raised blood pressure is the major cause of
stroke as well as an important risk factor for
ischemic heart disease, we propose that the blood pressure-lowering effect of
quercetin could be an important mechanism contributing to the reduced risk of
myocardial infarction and
stroke observed with fruit and vegetables-rich diets, and possibly with
flavonoid-rich diets.