Objective: To investigate the therapeutic effect of a combination of artemether and daphnetin against Plasmodium berghei ANKA strain in mice.
Methods: Groups of P. berghei infected mice were treated with various oral doses of artemether and daphnetin according to "4-day suppress assay". Thin blood smears were made on the fifth day after inoculation of parasites and the parasitemia reduction rate was calculated. The ED50 values obtained were plotted on isobolograms. A combined action of artemether and daphnetin was assessed.
Results: Artemether 0.4 mg/(kg x d) x 4d exhibited no detectable antimalarial effect, while artemether 0.4 mg/(kg x d) x 4d combined with daphnetin 7.7 mg/kg. d x 4d showed potent antiparasile efficacy. The ED50s of artemether in combination with daphnetin were lower than that of single artemether or daphnetin. The R-values were higher than 0.4, but lower than 2.7.
Conclusion: The combination of artemether with daphnetin showed an additive antiparasile effect.