In Vitro Antiplasmodial Activity and Cytotoxicity of Extracts of Selected Medicinal Plants Used by Traditional Healers of Western Cameroon

Medicinal plants play a key role in malaria control in Africa, especially in remote areas where health facilities are limited. In order to assess their acclaimed potentials, eleven extracts were prepared from seven selected plants commonly used in Western Cameroon, and tested both for their antiplasmodial activity and cytotoxicity. The antiplasmodial activity was assessed using Lactate Dehydrogenase Assay (pLDH) and the cytotoxicity estimated on LLC-MK2 monkey kidney epithelial cells. Seven extracts from five different plants were significantly active, with very weak or no cytotoxicity. The Dacryodes edulis leaves showed the highest activity (IC50 of 6.45？ g/mL on 3D7 and 8.2？ g/mL on DD2) followed by the leaves of Vernonia amygdalina (IC50 of 8.72 and 11.27？ g/mL on 3D7 and DD2 resp.) and roots of V. amygdalina (IC50 of 8.72？ g/mL on 3D7), Coula edulis leaves (IC50 of 13.80？ g/mL and 5.79？ g/mL on 3D7 and DD2 resp.), Eucalyptus globulus leaves (IC50 of 16.80？ g/mL and 26.45？ g/mL on 3D7 and DD2) and Cuviera longiflora stem bark (IC50 of 20.24？ g/mL and 13.91？ g/mL on 3D7 and DD2). These findings justify the use of five of the seven plants in malaria treatment by traditional healers of Western Cameroon. 1. Introduction Malaria is the world’s most important parasitic disease especially when Plasmodium falciparum is the causative agent. From the recent World Malaria Report, there were an estimated 225 million malaria cases, with 800,000 deaths among the 3 billion people at risk in 2009. About 91% of total deaths occurred in Africa with pregnant women and children under 5 years being the most affected groups of the populations [1]. Cameroon figures among the 18 countries bearing 90% of malaria deaths in Africa, with 71% of its population living in high-transmission areas [2]. In the western region of Cameroon, for example, malaria was shown to be the most important cause of infant mortality causing about 45% deaths and 54% hospitalizations for children under five [3]. In the absence of an effective vaccine, the fight against malaria relies mainly on chemotherapy and vector control. The resistance of Plasmodium falciparum to the commonly used antimalarial drugs including the newly introduced Artemisinins has resulted in resurgence in treatment failures [4, 5]. Hence, new highly efficacious and affordable antimalarial agents are urgently needed. For hundreds of years, plants have constituted the basis of traditional medicine systems and natural products have been a good source for drug development. Some examples are Quinine and Artemisinin that have been