Abstract
Isorhamnetin and quercetin produced endothelium-independent vasodilator effects in rat aorta, rat mesenteric arteries, rat portal vein and porcine coronary arteries. The effects of the two flavonoids were similar in arteries stimulated by noradrenaline, KCl, U46619 or phorbol esters but the two flavonoids were more potent in the coronary arteries than in the aorta. At high concentrations, they also induced a positive inotropic effect in isolated rat atria. Therefore, at least part of the in vivo effects of quercetin may result from its conversion to isorhamnetin which is the main metabolite of quercetin found in plasma. The arterial, venous and coronary vasodilator effects may contribute to the protective effects of flavonoids in ischaemic heart disease observed in epidemiological studies.
Abbreviations
cyclic AMP:Adenosine 3′:5′-cyclic monophosphate
cyclic GMP:Guanosine 3′:5′-cyclic monophosphate
Emax:Maximal effect
NO:Nitric oxide
pD2:Half-maximal effective concentration (as -log[M])
PMA:Phorbol 12-myristate-13-acetate
S.E.M.:Standard Error of the Mean
SIN-1:3-Morpholino-sydnonimine
SNP:Sodium nitroprusside
U46619:Thromboxane A2 mimetic
Key words
Quercetin - isorhamnetin - atria - coronary artery - portal vein
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Francisco Pérez Vizcaíno
Dept. Farmacología
Inst. Farmacología y Toxicología (CSIC)
Facultad de Medicina
Universidad Complutense
28040 Madrid
Spain
Phone: 34-913941472
Fax: 34-913941470
Email: fperez@ucmail.ucm.es
