Hypotensive action of Acacia catechu

Abstract The hypotensive action of an aqueous extract of ACACIA CATECHU (ACE) in laboratory mammals was studied using IN VIVO and IN VITRO preparations. It produced a dose dependent decrease in blood pressure of both anaesthetized dogs and rats. The vasodepressor effect could not be ascribed to the presence of cations nor induction of histamine release upon injection. In pharmacological antagonist studies, the hypotensive effect of ACE was not mediated via the α-adrenoceptor, β-adrenoceptor, muscarinic receptor, histamine receptors and autonomie ganglion. Captopril infusion potentiated the hypotensive response by prolonging its duration. Furthermore, ACE relaxed the isolated rat tail arteries in the arginine vasopressin or methoxamine preconstricted condition. It is concluded that ACACIA CATECHU is hypotensive and its action is probably bradykinin-related and ascribed to vasodilatation.