Antiplasmodial and cytotoxicity activities of some selected plants used by the Maasai community, Kenya

Malaria has continued to be a major global public health problem and a health concern in most of African countries. An estimated 350–500 million cases of malaria each year result in about one million deaths, mainly children under five. The rate of malaria infection is increasing rapidly partly due to drug resistance by the Plasmodium falciparum. The cost of the current drugs is prohibitive to the poor. There is therefore urgent need to identify new antimalarial agents that are effective, safe and affordable. In our continuous search for these new antimalarial compounds, extracts from five medicinal plants from the Maasai community in Kenya were tested against P. falciparum (D6; chloroquine sensitive and W2; chloroquine resistant strains). Of the tested total plant extracts, 5 crude extracts showed good antiplasmodial activity against D6 strain of P. falciparum with IC₅₀ values lower or equal to 14.3 μg/ml, 2 were moderately active with IC₅₀ values in between 26.6 and < 50 μg/ml. The petroleum ether extracts of the aerial parts and roots of Fuerstia africana demonstrated high antiplasmodial activity against the chloroquine sensitive antiplasmodial strain D6 (IC₅₀ 1.5 and 4.6 μg/ml, respectively with a selectivity index of 44 against vero cells). Manilkara discolor also exhibited promising antiplasmodial activity especially against D6 (IC₅₀ 11.5 and 26.6 μg/ml). In addition, ethyl acetate extract of the roots of Pentas lanceolata and the aerial parts of Sericocomopsis hildebrandtii demonstrated moderate antiplasmodial activity against D6 and W2 (IC₅₀ 14.3 and 16.51 μg/ml) respectively. F. africana therefore has high potential and can be pursued for the development of an antimalarial drug.