Abstract

ANTIMALARIAL AND ANTIPLASMODIAL ACTIVITIES OF EXTRACTS AND FRACTIONS OF ANACARDIUM OCCIDENTALE L. IN MICE EXPERIMENTALLY INFECTED WITH PLASMODIUM BERGHEI

Udo E. J.*, Nwanya J. C., Nduonofit N. E., Ekong U. E., Michael S. O., Atsuwe T. S..

Abstract

Malaria remains a major public health challenge, particularly in sub-Saharan Africa, where increasing resistance of Plasmodium parasites to existing antimalarial drugs necessitates the search for new therapeutic agents. This study evaluated the antimalarial and antiplasmodial activities of the ethanol leaf extract and solvent fractions of Anacardium occidentale in Swiss albino mice experimentally infected with Plasmodium berghei. Fresh leaves of A. occidentale were extracted with ethanol and fractionated into n-hexane, chloroform, ethyl acetate, n-butanol, and aqueous fractions. Qualitative phytochemical screening and acute toxicity studies were performed using standard procedures. The crude extract was administered orally at doses of 100, 200, and 250 mg/kg body weight, while each solvent fraction was administered at 200 mg/kg body weight. Antiplasmodial activity was evaluated using suppressive (4-day test), prophylactic, and curative models. Chloroquine (5 mg/kg) and pyrimethamine (1.2 mg/kg) served as standard drugs. Data were analysed using one-way analysis of variance (ANOVA) followed by Tukey’s post hoc test, with significance set at p < 0.05. Phytochemical screening revealed the presence of alkaloids, flavonoids, tannins, saponins, terpenoids, cardiac glycosides, combined anthraquinones, and phlobatannins. No mortality or signs of toxicity were observed in mice administered up to 5000 mg/kg of the crude extract. The crude extract exhibited dose-dependent antiplasmodial activity, with chemosuppression increasing from 29.90% at 100 mg/kg to 58.86% at 250 mg/kg. Among the solvent fractions, the ethyl acetate fraction demonstrated the highest suppressive (72.32%) and prophylactic (65.66%) activities, whereas the n-hexane fraction produced the greatest curative effect and longest mean survival time (17.10 ± 0.26 days). Chloroquine and pyrimethamine exhibited significantly higher antiplasmodial activities than all extract-treated groups (p < 0.05). The findings demonstrate that the ethanol leaf extract and solvent fractions of A. occidentale possess significant antimalarial and antiplasmodial activities against P. berghei infection. The ethyl acetate fraction showed the most potent suppressive and prophylactic effects, while the n-hexane fraction exhibited superior curative activity. These results support the traditional use of A. occidentale in malaria treatment and suggest that the plant may serve as a promising source of bioactive compounds for antimalarial drug development.

Keywords: Anacardium occidentale, antimalarial activity, antiplasmodial activity, Extracts, Fraction, Plasmodium berghei.