Hypotensive and Antihypertensive Effects of Total Aqueous Extract of Justicia secunda Vahl M. (Acanthaceae) in Rabbits

The total aqueous extract of the leaves of Justicia secunda (Acanthaceae) from 1.25 to 75 mg/kg of body weight (BW) induced a dose-dependent hypotension in rabbits. The hypertension induced by adrenaline at 5.10-4 mg/kg of BW is reduced by AJse administered at doses ranging from 10 to 30 mg/kg BW in dose-dependent manner (P less than 0.01). AJse, at 40 mg/kg BW, cancels completely the hypertension induced by adrenaline at 5.10-4 mg/kg BW and provokes in consequence a hypotension. Additionally, AJse at 10-30 mg/kg BW significantly reduces hypertension induced by the electrical stimulation of the sympathetic nerve fibers, and even cancel completely at 30 mg/kg BW or superior doses. This aqueous extract of leaves of Justicia secunda is thus hypotensive and antihypertensive in rabbits. The antihypertensive effect induced by AJse extract in the presence of adrenaline, or upon his release following stimulation of the sympathetic nerve fibers, indicates that this extract would act by inhibiting -adrenergic receptors. The total aqueous extract of Justicia secunda leaves therefore contains substances acting as beta-blockers. Hypotensive and antihypertensive properties of the total aqueous extract of Justicia secunda (Acanthaceae) justify the use of this plant in traditional medicine to treat high blood pressure.