In vitro antitrypanosomal activity of ethnopharmacologically selected Beninese plants

Sara Hoet a,*, Frederik Opperdoes b, Reto Brun c, Victor Adjakidjé d, Joëlle Quetin-Leclercq a
 
a Laboratoire de Pharmacognosie, Université Catholique de Louvain, Av. E. Mounier 72, UCL 72.30-CHAM, B-1200 Brussels, Belgium
b Research Unit for Tropical Diseases, Christian de Duve Institute of Cellular Pathology and Laboratory of Biochemistry, Catholic University of Louvain, Av. Hippocrate 74-75, B-1200 Brussels, Belgium
c Swiss Tropical Institute, Socinstrasse 57, CH-4002 Basel, Switzerland
d Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Nationale du Bénin, Abomey-Calavy, Benin

Abstract

The in vitro antitrypanosomal activity of methylene chloride, methanol and aqueous extracts of the leaves and twigs of five plant species traditionally used in Benin for the treatment of sleeping sickness were evaluated on Trypanosoma brucei brucei and their selectivity was analysed on Leishmania mexicana mexicana and J774 macrophage-like murine cells. The results showed that the four most active extracts had MIC values =19
g/ml (Hymenocardia acida twig and leaf, Strychnos spinosa leaf, Trichilia emetica leaf methylene chloride extracts). All these extracts had a lower activity on L. m. mexicana and J774 cells. Determination of the IC50 values of the methylene chloride leaf extracts on two strains of trypanosomes (T. b. brucei and T. b. rhodesiense) and two mammalian cell lines (L6 and J774 cells) showed that all extracts possessed some antitrypanosomal activity with IC50’s ranging from 1.5 to 39
g/ml. All were also toxic to the mammalian cells, but usually with higher IC50’s. The only exception was the S. spinosa methylene chloride leaf extract which had no toxicity on J774 cells. Although tannins have been identified in most of the species studied, they could not be detected in the most active extracts, just as alkaloids. The presence of flavonoids and quinones may at least in part explain the observed activities of some of the active extracts.

© 2003 Elsevier Ireland Ltd. All rights reserved.

Keywords: Antitrypanosomal activity; Cassia sieberiana; Hymenocardia acida; Pericopsis laxiflora; Strychnos spinosa; Trichilia emetica