Modes of Hypotensive Action of Dihydroquercetin in Arterial Hypertension.

We studied the effect of dihydroquercetin (20 mg/kg/day intragastrically for 6 weeks) on mean BP and macro- and microrheological blood parameters in hypertensive SHR rats; in vitro effect of dihydroquercetin on the tone in thoracic aorta rings isolated from hypertensive SHR rats were also examined. At the end of the treatment course, the mean BP in the experimental rats decreased by 11%; the left ventricular mass index by 2%, and whole blood viscosity by 7-10% in comparison with control SHR rats; erythrocyte aggregation half-time increased by 15%; plasma viscosity, hematocrit, and erythrocyte deformability did not change. In in vitro experiments, dihydroquercetin (10(-8)-10(-6)M) induced relaxation of the isolated thoracic aorta rings in a dose-dependent manner. Hence, the antihypertensive effect of dihydroquercetin results from the decrease in blood viscosity and vasodilation.