A flavonoid-rich diet increases nitric oxide production in rat aorta

1 Red wine intake is associated with a low risk of cardiovascular disease. This effect has been partly attributed to the action of polyphenolic compounds, which decrease the oxidation of plasma low density lipoproteins. Moreover, nitric oxide ((NO)-N-.) is a vasodilator and polyphenolic compounds induce endothelium-dependent vasorelaxation in vitro. 2 Here we studied whether a diet rich in dealcoholated red wine (DRW) increases acetylcholine-induced vasorelaxation and whether ingestion of DRW-, quercetin- or catechin-rich diets modifies the (NO)-N-.-cyclic guanosine-3',5'-monophosphate (cyclic GMP) pathway and superoxide anion (O-2(-)) release in aorta in a resting state in rats fed semi-purified diets containing either 35% (v w(-1)) DRW, 0.3% (w w(-1)) quercetin or 0.3% (w w(-1)) catechin for 10 days. 3 (NO)-N-.-mediated vasorelaxation induced by acetylcholine was greater in rats fed the DRW-rich diet than in those that received the control diet. 4 Expression of endothelial (NO)-N-. synthase (eNOS) was similar in the four dietary groups. The aortic rings of rats fed either the DRW-, quercetin-, or catechin-rich diets showed higher NOS C activity, (NO)-N-. production and cyclic GMP content than those of rats fed the control diet. No changes were observed in O-2(-) production. 5 In summary, diets rich in either DRW, quercetin or catechin induced endothelium-dependent vasorelaxation in rat aorta in a resting state through the enhancement of (NO)-N-. production, without modifying O-2(-) generation, thus the bioavailability of (NO)-N-. was increased. The increase in the (NO)-N-.-cyclic GMP pathway explains the beneficial effect of flavonoids at vascular level.