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RESUMELes plantes médicinales sont des véritables sources de molécules bioactives. L'objectif de la présente étude a été de tester les effets de l'extrait hydroéthanolique de Lippia multiflora sur le coeur isolé de crapaud et d'élucider son mécanisme d'action probable. Cet extrait a été obtenu après extraction aux solvants à polarité croissante. Le coeur de crapaud a été isolé et perfusé avec le ringer normal puis avec les différents produits selon le dispositif de Langerdhorff de mesure de la force et la fréquence des contractions du coeur. Les résultats obtenus montrent que l'extrait hydroéthanolique de Lippia multiflora provoque des effets inotrope et chronotrope positifs sur le coeur isolé de crapaud, semblables à ceux de l'adrénaline bien que moins marqués. Cet extrait semble provoquer l'augmentation de l'influx d'ions calcium consécutif à son action directe sur les récepteurs α1-adrénergiques cardiaques comme l'adrénaline. Les effets de cet extrait étant antagonisés par le propranolol et le vérapamil. Par ailleurs, cet extrait potentialise les effets inotrope et chronotrope positifs de l'adrénaline sur le coeur isolé de crapaud. Ces résultats suggèrent que l'extrait hydroéthanolique de L. multiflora provoque les effets inotrope et chronotrope positifs probablement suivant le même mécanisme que l'adrénaline. © 2016 International Formulae Group. All rights reserved.Mots clés : Lippia multiflora, inotrope, chronotrope, CaCl 2 , adrénaline, coeur.Effects of hydroethanolic extract of Lippia multiflora Moldenke on the heart isolated from toad ABSTRACT Medicinal plants are sources of bioactive molecules. The objective of this study was to test the effects of hydroethanolic extract of Lippia multiflora on the isolated toad heart and to elucidate its likely mechanism of action. This extract was obtained after extraction with solvents of increasing polarity. The toad heart was isolated and perfused with the normal ringer then with different products according to the Langerdhorff device for measuring the strength and frequency of heart contractions. The results obtained show that the A.W. ETOU OSSIBI et al. / Int. J. Biol. Chem. Sci. 10(6): 2617-2636 2618 hydroethanolic extract of Lippia multiflora produces positive inotropic and chronotropic effects on the isolated heart of toads, similar to those of adrenaline, although less marked. This extract seems to cause an increase in the influx of calcium ions following its direct action on cardiac α1-adrenergic receptors such as adrenaline. The effects of this extract are antagonized by propranolol and verapamil. Moreover, this extract potentiates the positive inotropic and chronotropic effects of adrenaline on the isolated heart of toad. These results suggest that the hydroethanolic extract of L. multiflora causes the positive inotropic and chronotropic effects probably following the same mechanism as adrenaline.

The present study focused on the diuretic activity of the essential oil (EO) of Cymbopogon densiflorus (Steud.) Stapf and the citral (majoritaire compound). The analysis of the chemical composition of this oil by gas chromatography coupled with mass spectrometry (GC/MS) made it possible to identify several molecules. It emerges from this study that only EO at 150 mg/kg causes significant diuretic activity (V.U.E = 168.39%) such as furosemide; the latter being modest (V.U.E = 143.62%) for citral at a dose of 75 mg/kg. In treated mice, removal of sodium was significant and potassium was spared compared to mice treated with distilled water. The diuretic effect of EO of C. densiflorus leaves demonstrated in the present study is a mode of action of this plant that justifies its use in traditional medicine against high blood pressure.

Desmodium velutinum (D. velutinum) is a plant of the family Fabaceae used in traditional Congolese medicine for the treatment of high blood pressure (HBP) or hypertension (HT). The present work evaluated the hypotensive activity and determined the phytochemical profile of the aqueous extract and