Anti-plasmodial, anti-trypanosomal and cytotoxic effects of Anthonotha macrophylla, Annickia polycarpa, Tieghemella heckelii and Antrocaryon micraster extracts

Abstract

Malaria and trypanosomiasis are protozoan diseases which pose a devastating challenge to human health and productivity especially, in Africa where their respective vectors (Female Anopheles mosquito and tsetse fly) abound. Various medicinal plants are used to treat these parasitic diseases. However, the scientific basis of their use and toxicological profiles have not been assessed. We have therefore, evaluated the anti-plasmodial, anti-trypanosomal and cytotoxicity activities of four African medicinal plant extracts namely, Anthonotha macrophylla leaf (AML), Annickia polycarpa leaf (APLE), Tieghemella heckelii stem bark (THBE) and Antrocaryon micraster stem bark (AMSBE) extracts in vitro against P. falciparum (W2mef laboratory strain), T. brucei (GUTat 3.1 strain) and mammalian RAW 264.7 macrophage cell line respectively. The most active anti-plasmodial extract was AML (IC50 = 5.0 ± 0.08 µg/mL with SI of 21.9). THBE also, produced the most effective ant-trypanosomal activity (IC50 = 11.0 ± 0.09 µg/mL and SI of 10.2) among the extracts. In addition, none of the extracts produced toxic effect in RAW 264.7 macrophage cell line expect APLE which was moderately cytotoxic and also produced the least SI in both anti-trypanosomal and anti-plasmodial assays. These results suggest that AML and THBE could offer safe and alternative therapy for malarial and trypanosomiasis. This is the first study to report the anti-trypanosomal and in vitro anti-plasmodial activities of these four plants. The cytotoxicity of the plant parts used are also being reported for the first time except for T. heckelii stem bark.