Effect of Tephrosia Vogelii Hook.f. Leave Extracts on the Isolated Heart of Toad: Hypothesis of the Mechanism of Action

Abstract

The ichtyotoxic plants contain substances, which could present a danger to the consumers of caught fish with it. The isolated heart of toad was used in this experimentation according to the modified method of Langendorff. It was a question of having collected the filtrate obtained from the grinding of leaves dried by Tephrosia vogelii in Lock-Ringer, in perfuse the isolated heart of toad with solutions of increasing concentrations by this filtrate. Then to measure the various peaks describing the variations of the contractions and the frequencies of the heart by means of a recorder on paper. Reference solutions were also used except the foliar extracts of T. Vogelii. T.vogelii (10-3 to 10-2mg/ml) reduce the amplitude of contraction (negative inotropic) and frequency (negative chronotropic) of the isolated heart of toad; of which both are in a dose-dependent manner (increased and cumulative). The threshold of the effect on contraction and frequency were 3x10-3mg/ml and 2x10-3mg/ml respectively with maximal effect being 10-2mg/ml for contraction and frequency. The rotenone (10-6M) just like T.vogelii (5.5x10-3mg/ml) decreases the contraction and frequency whilst ATP (10-6M) increases the two parameters. In presence of the rotenone or T.vogelii, the positive inotropic effect induced by ATP is reduced and a negative chronotropic effect is observed. We established that there is an antagonism between the action of the rotenone and the ATP; and that would be via the calcium. The effect of T.vogelii on the isolated heart of toad would have been cause by the rotenone.