Antiplasmodial Activity of Ethanolic Leaf Extract of Eucalyptus citriodora in Swiss Albino Mice Infected with Plasmodium berghei NK 65

Abstract

Malaria is a life-threatening disease and emergence of malaria parasite resistance to antimalarial drugs, has necessitated the need for discovery and development of an alternative to malaria medicine. This study assessed the ethanolic leaf extract of Eucalyptus citriodora for the presence of bioactive components qualitatively and efficacy of the extract against the malaria parasite. Standard methods were used to determine the bioactive components of the leaf extract. Twenty (20) albino mice of body weight between 18-25 g were randomised into 5 groups of four mice each for acute toxicity test, while twenty-four (24) mice were randomised into six groups of four mice each (group 1, 2, 3, 4, 5 and 6) for antiplasmodial activity. All the groups were infected with P. berghei, except group 3 (normal control). Group 4, 5 and 6 were treated with 0.2 mL of 200, 400 and 800 mg/kg body weight of extract respectively. Group 2 (positive control) were treated with 0.2 mL of 5 mg/kg body weight of chloroquine. Group 1 (negative control) were administered with 0.2 mL of normal saline, while group 3 (normal control) were administered with 0.2 mL of normal saline for four consecutive days. Phytochemical screening revealed the presence of alkaloids, saponins, tannins, anthraquinone, flavonoids and cardiac glycosides and the extract was found safe and nontoxic. The antiplasmodial investigation revealed a decrease in percentage parasitaemia level in mice of group 4, 5 and 6 (extract treated group) compared with mice of group 1 (infected and not treated). The parasitaemia reduction was higher in group 6 (800 mg/kg). This significant decrease (P<0.05) in percentage parasitaemia level in the study was dose and time-dependent. The study revealed the potency of E. citriodora leaf extract as a future herbal candidate for the treatment of human malaria infection.