Isolation, Characterization And Antimalarial Activity Of Bioactive Components From The Leaves Of Alchornea cordifolia (Schumach. & Thonn.) Mull. Arg:- Attah, Esther A

ABSTRACT

Alchornea cordifolia is known for its phytomedicinal properties including its antimalarial potentials. This research was aimed at isolation and characterization of bioactive components from the leaves of Alchornea cordifolia as well as investigating by in vitro, the antimalarial activities of its crude methanol extract and fractions of petroleum ether, dichloromethane, ethyl acetate and methanol, on human whole blood medium, infected with Plasmodium falciparum. Phytochemical analysis, antimalarial activity and spectral characterization were done using standard methods. Through phytochemical screening we discovered the presence of tannins, flavonoids, alkaloids, phenols, saponins, and cyanogenic glycosides. The result of the spectral analysis revealed two compounds shown to possess identical spectral properties but with a distinct addition of two olefinic protons on the NMR at C-22 and C-23 in the case of one compound. The two compounds possess a steroidal skeleton with molecular masses of 412 and 414 and molecular formulas of C₂₉H₄₈O and C₂₉H₅₀O respectively. The two compounds interpreted from the spectral results are Stigmasterol and β-sitosterol respectively. Based on the IR we also proposed a third possible structure as a stigmasterol analog. The third structure still of molecular formula C₂₉H₄₈O has an aldehydic functional group, CHO replacing the CH₃ on C-18 but with absence of OH on C-3. On antimalarial activity, the crude methanol extract and ethyl acetate fraction showed a good dose-dependent antimalarial activity with mean IC₅₀ values of Parasitaemia (P) = 12.2 and P = 12.94 respectively, while those of standard drugs, chloroquine and ACT, used as positive control were 13.38 and 9.2 respectively. These mean IC₅₀ values indicate that crude methanol extract and ethyl acetate fraction gave a better antimalarial activity than chloroquine but were not as good as ACT. Using one way ANOVA for statistical analysis we confirmed our significant results. Hence the leaves of Alchornea cordifolia possess promising bioactive components that showed significant antimalarial activity against Plasmodium falciparum and may give a better activity when they work in synergy. Thus, it will be potentially effective in the fight against malaria.