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Background and aim: Kalanchoe pinnata is an herbal medicine used in Cameroon against cardiovascular diseases. Hypertension and myocardial infarction are among key risk factors of cardiovascular diseases. This research aimed to investigate antihypertensive effect of Kalanchoe pinnata in salt loaded myocardial infarcted rats and possible mechanism of action on vascular smooth muscle. Experimental procedure: Thirty rats were equally distributed into six groups: neutral, negative and positive controls and three test groups (administered extract 50, 100 and 150 mg/kg). Hypertension was induced by salt loading (18%) meanwhile myocardial infarction was by injection of 100mg/kg isoproterenol. The 28 day-In vivo treatment was followed by evaluation of systolic and diastolic arterial pressures, and troponin level. Ten untreated rats were used for the in vitro study, to investigate vasorelaxant mechanism. Results and conclusion: Treated rats showed significant increase of systolic (46.3%) and diastolic (73.5%) pressures. Troponine level increased by 400%. Extract at highest dose (150mg/kg) reduced these increases by 29.1%, 41.3% and 52% respectively. Extract (1.5mg/mL) caused a vasorelaxation (62.79%) in the presence of endothelium. Endothelium removal did not significantly modify the effect of the extract in KCl pre-contracted rings. In the same way, in rings pre-contracted with phenylephrine, the extract (1.5mg/mL) did not significantly modify the relaxation induced by sodium nitroprusside. However, methylene blue, a NO-cGMP inhibitor significantly reduced (P |
