Malaria, cytotoxicity, Jatropha tanjorensis, Plasmodium falciparum, chemical finger-print
The in vitro antiplasmodial activity and cytotoxicity of extracts from Jatropha tanjorensis leaves was evaluated. The plant leaves were successively extracted into three (3) extract forms (aqueous extract, ethanolic extract and hydro-ethanolic (50:50 v/v)) using standard procedures. For quality control, high performance thin layer chromatography (HPTLC) was performed on extracts. Antiplasmodial activity was assessed in vitro by using a 3D7 chloroquine sensitive clone of NF-54 isolate of Plasmodium falciparum. Cytotoxicity of extracts against non-cancerous vero cell lines was determined with doxorubicin serving as the standard cytotoxic drug. The spectra from the chemical finger-print of the extracts revealed that the ethanolic extract contained eleven peaks in contrast to the hydro-ethanolic (eight peaks) and aqueous (six peaks) extracts. The ethanolic extract had the highest antiplasmodial activity (IC50 10.86 ± 1.52 ug/ml), low cytotoxicity (IC50 86.8 ± 4.8 ug/ml) and selectivity index (SI) of 8.0 when compared with the hydro-ethanolic (IC50plasmodial 48.0 ± 1.34 ug/ml, IC50vero cells 547 ± 9.4 ug/ml, and SI of 11.4) and aqueous (IC50plasmodial 44.0 ± 2.4 ug/ml; IC50vero cells > 1000 ug/ml) extracts. The antiplasmodial activity of the crude ethanolic extract was however moderate when compared with the standard antimalaria drug chloroquine (IC50 0.087 ± 0.0003 ug/ml). The results therefore suggest moderate antiplasmodial activity and low cytotoxicity of ethanolic extract of Jatropha tanjorensis leaves against chloroquine sensitive strain of Plasmodium falciparum. The antiplasmodial activity of the plant leaves supports local claims on its efficacy in the treatment of malaria infection.