Cardiodepressant Activity of 90% Alcoholic Extract of Terminalia Arjuna and its Probable Mechanism of Action

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.