Mechanism of Cardiovascular Action ofTerminalia arjuna

Abstract
Terminalia arjuna (Hindi name Arjuna, Family Combretacae) has been used in the treatment of cardiovascular disorders by Ayurvedic physicians. However, its properties have not been scientifically evaluated so far. Therefore, the present study was carried out to examine the underlying mechanism of the cardiovascular effects of aqueous solution of Terminalia arjuna extract. Intravenous (I. V.) administration of the extract was found to induce dose dependent decrease in blood pressure (B. P.) and heart rate (H. R.). These extracts also inhibited carotid occlusion response, without affecting the pressor responses, induced by intravenous injection of norepinephrine and by electrical stimulation of preganglionic fibres of the abdominal splanchnic nerve. Hypotension and bradycardia were also observed following the injection of the extract into the lateral cerebral ventricle and vertebral artery. The results of the present study show that the hypotensive and bradycardiac effects of T. arjuna are mainly of central origin.