Evaluation of lyophilisate aqueous extract of leaves from Eugenia dysenterica DC on cardiovascular system

Abstract

Despite advances in the treatment of hypertension, only a third of patients achieve optimal levels of arterial blood pressure (ABP), a fact that motivates the discovery of new medicines using medicinal plants. Within this context prepared from the leaves of Eugenia dysenterica DC. (ED) are employed commonly in the treatment of cardiovascular disorders, however, there is no data in the literature to describe the cardiovascular effects of ED. Therefore, this study aims to evaluate the possible hypotensive effect of lyophilized aqueous extract of leaves from ED and its effect on heart rate (HR) in normotensive anesthetized Wistar rats as well as the mechanisms involved in the possible effects. For this purpose, the animal will be anesthetized with urethane (1,5 mg/mL) and the femoral artery and vein will be cannulated for BP recording and intravenous administration, respectively. Dose-response curve will be obtained by i. administration of different doses of ED (1, 6, 10, 15 , 20, 30 and 60 mg/kg) and its relative effect on ABP. After that, the mechanisms involved in hypotensive effect will be investigated by analyses of: a) muscarinic receptor involvement by atropine blockade (1mg/kg); b) autonomic nervous system involvement by hexamethonium blockade (20mg/kg); c) NO participation by NOS blockade with L -NAME (10mg/mL/kg); d) participation of vasodilatory prostaglandins by blocking cyclooxygenase with indomethacin (20 mg/mL/kg). In addition, we will evaluate the contribution of extract tannin to hypotensive effect. This proposal may motivate further studies aimed at the development of new antihypertensive drugs from the Brazilian biodiversity.