Bio-Guided Assay Fractionation of Methanol Extract on Cysteine Protease of Plasmodium Falciparum

Many plants are employed traditionally in the treatment of malaria in Nigeria but very few are explored to the fullest. This research work is designed to study the antimalarial activity of Chrozophora senegalensis via cysteine protease inhibitory effect. The extracts of the plant were prepared by cold maceration with 4 different solvents, n-hexane, ethyl ether, methanol, and aqueous. Investigation against malarial cysteine protease with the four extracts shows highest inhibitory activity of the enzyme in the methanol extract with percentage inhibition of 80% and 76%, 29%, and 15% for aqueous, n-hexane and ethyl ether respectively. Fractionation of the most active extract (methanol extract) gave rise to 50 fractions which were pooled to ten different fractions according to their similarities in Rf values. The ten fractions were further tested against the enzyme malarial cysteine protease. Fraction 3 showed highest inhibitory activities which on gas chromatography/mass spectroscopy characterization which revealed the presence of nitro-benzoic acid and ellagic acid alone side other fatty-acids and their derivatives. The best inhibitory activity through the anti- plasmodia effect of the methanol extract of the plant could be due to its cysteine protease inhibitory activity. Further work on fraction 3 will be required to characterized and isolate the active lead compound.