Pharmacological studies on hypotensive, diuretic and vasodilator activities of chrysin glucoside from Calycotome villosa in rats

The present study was undertaken in normotensive anaesthetized male rats that received a continuous perfusion of a chrysin glucoside isolated from the flowers and leaves of Calycotome villosa subsp intermedia at a dose of 2.5 mg/kg, or furosemide (control diuretic) at a dose of 0.5 mg/kg. Compared with the control rats receiving NaCl (0.9%), the urine flow, glomerular filtration and electrolyte excretion (Na + , K + ) increased significantly in rats treated with chrysin glucoside ( p < 0.001). A similar effect was observed in the rats perfused with furosemide. Intravenous injections of bolus doses (1–3 mg/kg) of the chrysin glucoside to anaesthetized rats elicited an immediate and dose‐dependent decrease in mean arterial blood pressure (MABP). Pretreatment of the rats with the nitric oxide synthase inhibitor, l ‐NOArg (10 mg/kg), reduced partially, but significantly ( p < 0.01), the maximal decrease in MABP elicited by chrysin glucoside. In the rat isolated aorta preparation, chrysin glucoside (10–100 µ m ) inhibited in a concentration‐dependent manner the noradrenaline (1 µ m ) induced contractions (IC 50 = 52 µ m ). This relaxant activity of chrysin glucoside was significantly reduced by incubation of the endothelium‐intact rings with l ‐NOArg (100 µ m ), (80 ± 4.7% vs 48 ± 5.06% in the absence of l ‐NOArg). In conclusion, these results demonstrate a diuretic and hypotensive action of a chrysin glucoside from Calycotome villosa in anaesthetized rats and indicating an action on renal function, and an active vascular relaxation mediated partially through nitric oxide release. Copyright © 2007 John Wiley & Sons, Ltd.