1 The effects of an oral daily dose (10 bg kg(-1)) of the flavonoid quercet
in for 5 weeks in spontaneously hypertensive (SHR) and normotensive Wistar
Kyoto rats (WKY) were analysed.
2 Quercetin induced a significant reduction in systolic (-18%), diastolic (
-23%) and mean (-21%) arterial blood pressure and heart rate (-12%) in SHR
but not in WKY rats.
3 The left ventricular weight index and the kidney weight index in vehicle-
treated SHR were significantly greater than in control WKY and these parame
ters were significantly reduced in quercetin-treated SHR in parallel with t
he reduction in systolic blood pressure.
4 Quercetin had no effect on the vasodilator responses to sodium nitropruss
ide or to the vasoconstrictor responses to noradrenaline or KCI but enhance
d the endothelium-dependent relaxation to acetylcholine (E-max = 58 +/- 5%
vs 78 +/- 5%, P < 0.01) in isolated aortae.
5 The 24 h urinary isoprostane F-2<alpha> excretion and the plasma malonyld
ialdehyde (MDA) levels in SHR rats were increased as compared to WKY rats.
However, in quercetin-treated SHR rats both parameters were similar to thos
e of vehicle-treated WKY.
6 These data demonstrate that quercetin reduces the elevated blood pressure
, the cardiac and renal hypertrophy and the functional vascular changes in
SHR rats without effect on WKY. These effects were associated with a reduce
d oxidant status due to the antioxidant properties of the drug.