In vivo anti-malarial activities of methanol and aqueous extract of stem bark of Eucalyptus camaldulensis on Plasmodium berghei-berghei

Abstract

Malaria is a life-threatening infectious disease transmitted by mosquitoes, affecting both humans and animals. It is a blood-borne illness caused by the Plasmodium parasite.  This research was aimed at probing the in vivo anti-malarial effects of aqueous and methanol extracts of Eucalyptus camaldulensis stem bark. Two hundred (200) grams of the pulverized plant material were sequentially macerated in 900 mL of methanol and water for 24 hours, respectively. In each case, the mixture was filtered using the Whatman filter paper. The filtrate was then evaporated to dryness in a water bath to obtain the crude extract. Twenty-seven (27) albino mice of the same sex, weighing 18-25 g, were selectively grouped into five groups of three mice each. Groups 1, 2, and 3 were infected but treated with the aqueous and methanol extracts of Eucalyptus camaldulensis stem bark at doses of 50, 100, and 150 mg/kg body weight for five days. Group 4 animals were infected and treated with 25 mg/kg per body weight of chloroquine, while group 5 was left untreated and served as a negative control group. It was detected that the animals administered with both extracts showed a significant (p<0.05) decrease in parasitemia when compared with the negative control group. However, the group treated with chloroquine at 25 mg/kg body weight showed a significantly lower parasitemia (p<0.05) when compared with the groups treated with both methanol and aqueous extract. The dose-by-dose comparison of the anti-malarial effect of the two extracts at the dose of 150 mg/kg body weight indicates that the methanol extract exhibited higher anti-malarial activity when compared with the aqueous extract at the same dose. The results of this study indicate that the methanol and aqueous extracts of the stem bark of Eucalyptus camaldulensis exhibit anti-malarial activity, supporting its traditional medicinal use.