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

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) is a vasodilator and polyphenolic compounds induce endothelium‐dependent vasorelaxation in vitro . 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‐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.• NO‐mediated vasorelaxation induced by acetylcholine was greater in rats fed the DRW‐rich diet than in those that received the control diet. Expression of endothelial • NO 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 activity, • NO production and cyclic GMP content than those of rats fed the control diet. No changes were observed in O 2 .− production. 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 production, without modifying O 2 .− generation, thus the bioavailability of • NO was increased. The increase in the • NO‐cyclic GMP pathway explains the beneficial effect of flavonoids at vascular level.British Journal of Pharmacology (2002) 135 , 910–916; doi: 10.1038/sj.bjp.0704534