Effects of lemon decoction on malaria parasite clearance and selected hematological parameters in Plasmodium berghei ANKA infected mice

Abstract Background Citrus plants particularly lemon (Citrus limon L.) concoctions are ethno-medically used for treatment of infectious diseases including malaria. Therefore, we set an experiment to investigate the effects of lemon decoction in mice infected with Plasmodium berghei ANKA parasites. Methods Antimalarial activity was determined using Rane’s curative test on 25 Theiler’s albino mice. Twenty mice were each injected with 2 × 107 infected red blood cells (iRBCs). The mice were divided into four groups, consisting of five mice per group. Each group received an oral dose of either 5% carboxymethyl cellulose/placebo (negative infected control), lemon decoction (Citrus limon [CILI extract]) alone or a combination of artemether/lumefantrine (A/LU, 28 mg/kg) and CILI extract and A/LU alone. A fifth group of mice consisted of uninfected mice as parasite-negative control. Results Within 72 hours after initiation of treatment, the mean percentage parasitemia ± standard deviation of the CILI extract group (24.2% ± 9.83%) was lower compared to placebo group (40.0% ± 14.78%), p = 0.037. CILI extract group was found to have an increased survival rate (11 days ± 1.6 days) as compared to placebo group (8.6 days ± 3.4 days), p = 0.226. Mice in the combination group (A/LU + CILI extract) had the highest mean counts in terms of hemato-immunological parameters, whereas those in the CILI extract alone had the lowest hematocrit levels. The study also found that mice that received a combination of CILI extract and A/LU exhibited a decreased lag time with regards to time required to clear 99% of parasites (58.8 h vs. 64.2 h, p = 0.681) as compared to the A/LU alone group. Conclusion Lemon decoction demonstrated antimalarial activity in mice infected with P. berghei ANKA through parasites suppression by 39% as compared to those received placebo. However, when used alone, lemons did not suffice as a cure but in combination with standard antimalarials, lemons promoted early parasite clearance with an improved hematological parameters.