Cardiodepressant activity of 90% alcoholic extract of Terminalia arjuna and its probable mechanism of action.

ABSTRACT

Background: Terminalia arjuna is being used in various cardiovascular diseases as cardiotonic, diuretic & in hypercholesterolemia. Studies conflict each other for its mechanism of action. This study aims to investigate effect of 90% alcoholic extract of Terminalia arjuna on in vitro isolated rabbit’s heart & to find its probable mechanism of action. Objective: To study the preliminary pharmacological effects of 90% alcoholic extract of Terminalia arjuna in-vitro on isolated heart, coronary blood flow, and to study its probable mechanism of action. Material & Methods: Effect of Terminalia arjuna was observed on heart rate, coronary blood flow, amplitude on in vitro isolated perfused rabbit’s heart mounted on langendorff apparatus & further cholinergic & adrenergic blockers were used to study the mechanism of action. Six experiments were conducted for each parameter & data was analysed using Student’s t test. Results: Terminalia arjuna causes mean percentage decrease of 7.26%, 9.31% & 20.51% in heart rate, decrease of 10.34%, 16.64%, 20.51% in coronary blood flow & decrease of 15.11%, 12.61%, 11.65% in amplitude at 25μg, 50μg & 100μg doses respectively. The decrease in heart rate, coronary blood flow & amplitude persists even after cholinergic & adrenergic blockers suggesting that cholinergic & adrenergic receptors are not involved in mechanism of Terminalia arjuna. Conclusion: Terminalia arjuna cardiodepressant effect does not involve cholinergic & adrenergic receptors.