ABSTRACT
Malaria is the world's most important parasitic disease especially when Plasmodium falciparum is the cause of most of the mortality and morbidity. Malaria has been challenging human health and losing the lives of many people since long period of time. Malaria has been one of the most extensively studied parasitic infectious diseases for millennia and the recent failure of chemotherapy through parasite resistance to drugs and alternative therapy is paramount. The present study was aimed at evaluating the effect of ethanol extracts of vernonia amygdalina leaf in cerebral and cerebellar cortices of young mice inoculated with plasmodium berghei. Sixty (60) young mice aged 5-7 weeks, weighing between 10-15g were divided into three categories in which category A, B, C contain twenty mice each which represent the Suppressive, Curative, and the Prophylactic design. Each category contains five groups with four mice in each group. In all the categories each Group 1 was administered distilled water, Group 2 was inoculated with P. berghei parasite, Group 3 was treated with P. berghei + ELVA 2500mg/kg, Group 4 was treated with P. berghei + ELVA 1250mg/kg and Group 5 was treated with P. berghei + 10mg/kg of Chloroquine respectively where ELVA is Ethanol Leaf extract of Vernonia amygdalina. In the Suppressive design the mice were inoculated with P. berghei parasite three hours after then parasite load is quantified follow by treatment with ELVA and on the 4th day parasite quantification and sacrifice is done. In the Curative design the mice were inoculated with P. berghei parasite 48 hours after then parasitemia level was taken follow by treatment with ELVA, on the 7th day parasite quantification and sacrifice was carried out. In the prophylactic design the mice were treated with ELVA for 72 hours thereafter inoculation with P. berghei parasite was carried out with parasite quantification noted up till the 8th day before sacrifice. The mice were sacrificed and brain tissues were removed and fixed in Bouin's fluid, processed for histopathological studies using Haematoxyline and Eosin (H and E), and Cresyl Echt Violet stains. The result for the suppressive design indicates that the mean percentage parasitemia in group 3 mice treated P. berghei + ELVA 2500mg/kg (2.84�0.10) was significantly lower (P?0.001) compare to Group 2 (4.44�0.16), group 4 (3.28�0.12) and group 5 (3.34�0.13). The result from the curative design shows that the parasitemia level of the mice in group 3 (2.48�0.22) was significantly lower compare to Group 2 (4.34�0.57) and group 4 (3.76�0.35) group 5 (2.64�0.10) with a (P value) of 0.015. The ethanol leaf extract of V. amgydalina exhibited different degrees of suppression at the doses (1250 and 2500) mg/kg and Pyrimethamine 1.2mg/kg which were (72.7, p<0.057; 61, p<0.057 and 76.2%, p<0.057) respectively as compared to normal control group. For the mean calculation of the level of parasitemia the result indicates that there is no significant difference observed in the group. In the suppressive and curative design, the histopathological changes in cerebral and cerebellar cortices of the young mice inoculated with P. berghei parasites and the effects were ameliorated when treated with ELVA when compared with the control. However, in the prophylactic design ELVA doesn't not ameliorate the effects of the inoculated parasite when compare to the suppressive and curative. Thus, the present study has established that ethanol extract of Vernonia amygdalina leaf at doses of 2500 mg/kg and 1250 mg/kg was able to ameliorate the effects of Malaria parasite inoculated and may justify the local usage by the traditionalist and the mass population in endemic areas that are exposed to the malaria parasite.