Biological and Phytochemical Investigations on Caesalpinia benthamiana, a Plant Traditionally Used as Antimalarial in Guinea

Caesalpinia benthamiana is widely used as antimalarial in Guinean traditional medicine. Leaf extracts of the plant were tested for their in vitro antiprotozoal activity against Trypanosoma brucei brucei and T. cruzi and the chloroquine-sensitive Ghana strain of Plasmodium falciparum along with their cytotoxicity on MRC-5 cells. The methanolic extract showed the strongest antiprotozoal activity against P. falciparum (IC(50) 4 μg/ml), a good activity against T. brucei (IC(50) 13 μg/ml), and a moderate activity against T. cruzi (IC(50) 31 μg/ml) along with an IC(50) on human MRC-5 cells of 32 μg/ml. Bioassay-guided fractionation from the methanolic extract led to antiplasmodially active subfractions. A prospective, placebo-controlled ethnotherapeutic trial assessed the antimalarial effectiveness and tolerability of C. benthamiana syrup administered orally to children with uncomplicated malaria as compared with chloroquine syrup. Phytochemical screening of the leaf extracts indicated the presence of flavonoids, terpenoids, tannins, saponins, and iridoids.