3.8. In Vivo Studies

The in vivo antimalarial assay was done based on a 4-day suppressive test using mice. The evaluation of the antimalarial activity against the methanolic solutions of the samples and Artesunate sensitive Plasmodium berghei (NK 65) was carried out according to a standard protocol of Peter’s 4-day suppressive test [56]. Each of the 12 healthy experimental mice was inoculated intraperitoneally on the first day (Day 1). The infected mice were weighed and randomly divided into four groups of three mice each and four hours post inoculation were treated orally thereafter 24, 48, and 72 h post inoculation. For groups 1 and 2, 25 mg of sample/kg of mouse and 50 mg of sample/kg of mouse was administered orally for four consecutive days. For group 3, 5 mg of Artesunate/kg of mouse was administered while group 4 was given 5 mL of distilled water/kg of mouse for four consecutive days. On day 4 post inoculation, one drop of blood was taken from the tail of each experimental mouse and smeared on a microscope slide to make a thin film [57]. The thin films were fixed with methanol, stained with 10% Giemsa solution at pH 7.2 for 10 min, and examined microscopically. Parasitemia level was determined by counting the number of parasitized erythrocytes out of 100 erythrocytes per field in 4 random fields under a light microscope at magnification (×100) while average percentage parasitemia suppression was determined by comparing the parasitemia in the control group with the treated group.

where pc = average parasitema in the control group, pt = average parasitemia in the treated group [58].