Efficacy of (±)-taxifolin from Larix sibirica (Mûnchh.) Ledeb. on blood pressure in experiments in vivo

The cardiovascular pathology is one of principal causes of death around the world. P-vitamin and antioxidant effects of flavonoids are well-known, however the mechanism of their action is not clear. The aim of the present work was to investigate the efficacy of taxifolin on a vascular tone booth blood pressure (BP) in the model of spontaneously hypertensive rats (SHR). (±)-taxifolin was isolated from Larix sibirica wood (OJSC “Diod). Throughout the experiment male SHR rats (180–230g; age of 3 months breeder: Rappolovo, St-Petersburg, Russia) were used. All animals were kept in a room maintained under environmentally controlled conditions of 20–23°C, relative humidity –50–70%, and 12h light–12h dark cycle. All animals had free access to water and standard food. Taxifolin (in starch suspension) was administered intragastrically daily in 14 days, in doses 10, 20, 50 and 150mg/kg. Enalapril maleate (KRKA; 2mg/kg) and atenolol (AO “Pliva“; 10mg/kg) were used as reference preparations. The control group received vehicle only. Systolic and diastolic blood pressure, diuresis, electrocardiogram (II standard leads) were monitored in rats. It was established, that taxifolin in doses 10, 20, 50 and 150mg/kg has no diuretic effect. Taxifolin caused a manifest decrease of blood pressure. The most positive results were observed at use of a dose of 20mg/kg. Taxifolin had more expressed influence on the level of systolic BP. The decrease of myocardium stress was observed at the dose of taxifolin over 20mg/kg that was shown in normalization of R wave amplitude on an electrocardiogram. The effect of taxifolin was similar to reference preparations.