Assessment of cytotoxicity and antiplasmodial activities of <I>Prosopis africana</I> leaf extracts

Abstract

Malaria is a major health concern in Sub Saharan Africa and there are few effective treatment options. Nigeria has diverse flora with potent antimalarial phytochemicals and high ethnomedicinal plants uses. This study investigated the phytochemicals, Cytotoxicity and in-vitro antiplasmodial activity of ethnomedicinal plant which is Prosopis africana. Crude ethanol extract and macerated fractions from the ethnomedicinal plant were screened for major classes of antiplasmodial phytochemical compounds i.e., terpenoids, alkaloids, flavonoids, anthraquinones and Steroids. The antiplasmodial assay was conducted at 5% parasitaemia for 24 and 48 hours, against P. falciparum. Artemether-Lumefantrine was used as a positive control while 0.5% DMSO in RPMI 1640 medium was used as negative control. Moreover, all plant extract and fractions of P. africana were found to be effective in vitro for antiplasmodial activity, they demonstrated remarkable bioactivities at all concentrations; Methanol fraction (Pa-05) shows the highest activity with percentage elimination of 83.9% at 625µg/ml, 87.5% at 1250µg/ml, 92.9% at 2500µg/ml and 96.4% at 5000µg/ml. However, all the extract fractions have shown a good activity against the Brine Shrimp nauplii larvae. Crude Ethanol extract (PA-01) and n-Hexane fraction displayed the highest activity (LC₅₀ 58.482µg/ml and 75.462 µg/ml) respectively. However, the results suggested that extracts of P. africana showed the most curative anti-plasmodia effect in infected blood which may be attributed to the presence of phytochemical constituents such as a alkaloids, flavonoids, and terpenoids.

Keywords: Ethanol extract, Fractions, Phytochemicals, Cytotoxicity and Antiplasmodial