Antihypertensive effects of the flavonoid quercetin in spontaneously hypertensive rats

Abstract

1 The e ects of an oral daily dose (10 mg kg 71 ) of the¯avonoid quercetin for 5 weeks in spontaneously hypertensive (SHR) and normotensive Wistar Kyoto rats (WKY) were analysed. 2 Quercetin induced a signi®cant reduction in systolic (718%), diastolic (723%) and mean (721%) arterial blood pressure and heart rate (712%) in SHR but not in WKY rats. 3 The left ventricular weight index and the kidney weight index in vehicle-treated SHR were signi®cantly greater than in control WKY and these parameters were signi®cantly reduced in quercetin-treated SHR in parallel with the reduction in systolic blood pressure. 4 Quercetin had no e ect on the vasodilator responses to sodium nitroprusside or to the vasoconstrictor responses to noradrenaline or KCl but enhanced the endothelium-dependent relaxation to acetylcholine (E max =58+5% vs 78+5%, P50.01) in isolated aortae. 5 The 24 h urinary isoprostane F 2a excretion and the plasma malonyldialdehyde (MDA) levels in SHR rats were increased as compared to WKY rats. However, in quercetin-treated SHR rats both parameters were similar to those 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 e ect on WKY. These e ects were associated with a reduced oxidant status due to the antioxidant properties of the drug.

Quercetin sensitizes human hepatoma cells to TRAIL‐induced apoptosis via Sp1‐mediated DR5 up‐regulation and proteasome‐mediated c‐FLIPS down‐regulation

“…For example, chronic quercetin treatment was shown to lower blood pressure or prevent the development of hypertension in various experimental models [Duarte et al, 2001;Perez-Vizcaino et al, 2006]. Consumption of quercetin, enriched in onions and apples, was found to be inversely associated with lung cancer risk [Le Marchand et al, 2000].…”

“…Quercetin, one of the major dietary flavonoid enriched in various fruits and vegetables, has been reported to exert a broad range of pharmacological effects, including antioxidant and anti-inflammatory activities [Lamson and Brignall, 2000]. For example, chronic quercetin treatment was shown to lower blood pressure or prevent the development of hypertension in various experimental models [Duarte et al, 2001;Perez-Vizcaino et al, 2006]. Consumption of quercetin, enriched in onions and apples, was found to be inversely associated with lung cancer risk [Le Marchand et al, 2000].…”

Effects of taxifolin on the activity of angiotensin-converting enzyme and reactive oxygen and nitrogen species in the aorta of aging rats and rats treated with the nitric oxide synthase inhibitor and dexamethasone

“…Thus, it was shown that quercetin at a dose of 2.5 mg/kg/day suppresses vessel remodeling in mice deficient in apolipoprotein E (Hayek et al 1997). At a dose of 10 mg/kg, it decreases blood pressure in spontaneously hypertensive rats (Duarte et al 2001), as well as suppresses hypertension and removes all pathological changes in vessels and the heart of rats treated with L-NAME; at a dose of 5 mg/kg, some effects of quercetin were less pronounced than at a dose of 10 mg/kg (Duarte et al 2001). Thus, in the experiments with rats, quercetin at doses of 3-10 mg/kg/day reduces vessel remodeling.…”

“…In his review, Reed (2002) listed the following effects of flavonoids: suppression of oxidation of low-density lipids (LDL), suppression of thrombocyte aggregation, inhibition of enzymes mediating the response of immune cells to LDL and their absorption by epithelium macrophages, induction of endothelium-dependent vasodilation, and reduction of the total and LDL cholesterol. There is evidence indicating that the key effect of flavonoids in reducing the risk of atherosclerosis is a decrease of the oxidative stress in vessels (Duarte et al 2001;Galisteo et al 2004;Hishikawa et al 2005;Grassi et al 2010). For example, the flavonoid quercetin diminishes the concentration of isoprostane F2a and malondialdehyde (markers of oxidative stress and peroxidation, respectively) (Morrow and Roberts 1996;Kitts et al 1998;Duarte et al 2001) in rat urine and raises the concentration of the endogenous antioxidant glutathione (Galisteo et al 2004).…”

“…There is evidence indicating that the key effect of flavonoids in reducing the risk of atherosclerosis is a decrease of the oxidative stress in vessels (Duarte et al 2001;Galisteo et al 2004;Hishikawa et al 2005;Grassi et al 2010). For example, the flavonoid quercetin diminishes the concentration of isoprostane F2a and malondialdehyde (markers of oxidative stress and peroxidation, respectively) (Morrow and Roberts 1996;Kitts et al 1998;Duarte et al 2001) in rat urine and raises the concentration of the endogenous antioxidant glutathione (Galisteo et al 2004). A cardinal regulator of the concentration of reactive oxygen species (ROS) and, consequently, of oxidative stress in vessels is the product of angiotensinconverting enzyme (ACE) angiotensin II (Dzau 2001;Munzel and Keaney 2001).…”