Evaluation of the effect of the hydroalcoholic extract of Tanghinia venenifera Poir. (Apocynaceae) leaves on cardiac activity

This work aimed to investigate the effect of the hydro alcoholic extract of Tanghinia venenifera (Apocynaceae) leaves on experimentally induced failing isolated frog heart. The extract was perfused according to Langendorff retro perfusion method to assess its effects on contractile force, heart rate, and filling time. It was perfused through the sinus venosus to evaluate its effect on cardiac output. At concentration of 0.75 mg/mL, the extract increases the cardiac output from 24.6 ± 0.34 mL/minute to 54 ± 0.69 mL/minute, it also increases the filling time from 0.08 ± 0.002 seconds to 0.22 ± 0.005 seconds. It induces an increase of 0 to 67.12 ± 0.69 % of the contractile force compared to the experimentally induced failed heart (p < 0.05). It decreases the heart rate from 43.5 ± 0.173 beats per minute in the absence of the extract to 27.33 ± 0.305 beats per minute in its presence at 0.75 mg/ml (p < 0.05). These results demonstrate that the hydro alcoholic extract of Tanghinia venenifera improves cardiac output and exerts a cardiotonic effect through positive inotropic, positive lusitropic, and negative chronotropic actions. These effects are typical of cardiac glycosides activities