Evaluation of the antihypertensive activity of total aqueous extract of Justicia secunda Valh (Acanthaceae)

Our study aim at contributing to establish the scientific basis for the use of Justicia secundaVahl. (Acanthaceae) in the traditional treatment of hypertension in Cote d’Ivoire. We used a total aqueous extract of leaves of J. secunda (TAEJS). The experimental device used for recording blood pressure in the rabbit is based on the principle of Ludwig mercury manometer. TAEJS between 5.55 and 55.55 mg/kg causes reversible dose-dependent hypotension. TAEJS caused drops in blood pressure ranging between 7.93 ± 3.02 and -8.41 ± 5.2% compared to normal blood pressure of rabbits. Fifty percent effective dose of TAEJS is 26.18 mg/kg. Just like hypotension induced by acetylcholine, that caused by TAEJS at dose of 26.18 mg/kg in rabbit is progressively inhibited by atropine dosed between 3×10-5 and 3×10-1mg/kg. However, for a dose of atropine as high as 3×10-1 mg/kg, this inhibition is not total. Hypotension induced by TAEJS dosed at 26.18 mg/kg was 58 ± 2.1% in the absence of atropine, and decreased from 45.3 ± 2.11 to 5.09 ± 0.96% with doses of atropine between 3×10-5 and 3×10-1 mg/kg. The increasing doses of TAEJS, between 22.22 and 55.55 mg/kg reduced significantly the hypertension induced by adrenaline dosed at 5.78×10-4 mg/kg from 60.8 ± 1.29% to -5.91 ± -1.22%. Pharmacological studies of TAEJS on blood pressure of rabbits showed that extract of our plant has a potential antihypertensive effect which is due to the presence of several active substances whose nature remains to be determined.