Antagonistic Effect of Vitamin E on the Efficacy of Artesunate Against Plasmodium Berghei Infection in Mice

The effect of antioxidant (Vitamin E) on the efficacy of Artesunate was investigated using Plasmodium berghei infected mice. Fifty (50) adult albino mice weighing between 15-25g were used for this study. There were five groups of ten animals each per group. Group I was the normal control group without the parasite and untreated, group II was infected with malaria parasite and 0.9% normal saline was administered, group III was infected with the parasite and treated with artesunate, group IV was infected with the parasaite and vitamin E was administered and group V was infected with the parasite and combination of artesunate and vitamin E were administered. Parasitaemia level and haematocrit (PCV) were monitored upon the administration of antimalaria drug - artesunate, vitamin E, normal saline and combination therapy of both vitamin E and artesunate. The life span of the infected mice was found to be between the 7th and the 10th day post inoculation, while the LD50 of the parasite was 156626.2 parasite/μl of blood. Artesunate was observed to rapidly clear the parasite with parasitaemia level of 21632.4 ± 513.3 parasite/μl on the 6th day, 11209.9 ± 363.7 parasite/μl on the 7th day, 1359.7 ± 14.3 parasite/μl on the 8th day, 7.8 ± 2.4 parasite/μl on the 9th day and zero parasitaemia on the 10th day. The effect of artesunate was significantly reduced when co-administered with vitamin E (p < 0.05) with parasitaemia 30542 ± 362.5 parasite/μl on the 6th day, 24705.2 ± 489.9 parasite/μl on the 7th day, 15485.0 ± 563.2 parasite/μl on the 8th day, 947.6± 37.8 parasite/μl on the 9th day and 8.0 ± 2.7 parasite/μl on the 10th day. The study suggests that co-administration of vitamin E with artesunate could reduce the efficacy of artesunate in malaria infection