Rationale for thishypotheses was based on data from (i) normotensive humans wherein acute administration of200 mg quercetin increased plasma quercetin and NO metabolite concentrations whiledecreasing endothelin-1(42), (ii) hypertensive rats in which quercetin attenuated hypertension and/orvascular dysfunction in a NO-dependent manner(43–45) and (iii) in vitro studies wherein quercetin decreasedcellular production of endothelin-1(46,47) and endothelial-derived adhesion molecules(48,49). This evidence concerns the gene EDN1 and hypertensive disorder.