Effect of Annickia polycarpa (Stten and Mass.) Annonaceae, leaf extract on chemo-suppression of hyperparasitemia, body weight, hematological indices and survivor time of Plasmodium berghei infested mice in the Peter’s test

Abstract

Background: Malaria is an infectious disease that is spread through the bite of female anopheles mosquito resulting in the death of hundreds of thousands of people per year. Medicinal plants provide crude extracts and purified compounds for malaria treatment. Annickia polycarpa is one of such plants whose bark is used for this purpose. However, the antimalaria effect of its leaf is not known. We hereby report the investigation of antimalaria effect of A. polycarpa leaf. Methods: Antimalaria effect of the ethanol extract of A. polycarpa leaf (APLE) was investigated in P. berghei infested ICR mice in the Peter’s test. The effect of the extract on development and chemo-suppression of hyperparasitemia, reduction in body weight and mean survival time were evaluated. Full blood count analysis on the infected mice were performed to determine the effect of treatment with APLE on hematological indices such as red and white blood cells and platelets. Acute toxicity and phytochemical tests of the extract were also performed. Results: APLE administered orally at 50, 200 and 400 mg/kg produced profound dose-dependent chemo-suppressive effect of 89.37 – 95.50 % of P. berghei after 4 consecutive days of treatment which compares with 86.22 % obtained for Quinine 30 mg/kg i.m. under the same regimen. APLE also protected the mice against reduction in body weight associated with malaria which was P < 0.05 at 50 mg/kg. Furthermore, APLE promoted dose-dependent mean survival time in the Kaplan-Meier curve. Only 25.0 % of mice in the negative control group survived after 30 days compared to 100 % survival for mice in APLE 400 mg/kg and Quinine 30 mg/kg groups. The results from the full blood count shows that APLE caused (P < 0.05) dose dependent increase in RBC, HGB, HCT, WBCs, lymphocytes and platelets. The LD50 of APLE was above 5000 mg/kg p.o. Conclusions: APLE showed profound antimalaria effect with very high margin of safety. Hematological alterations that resulted from treatment of with APLE indicate significant improvement in general health and safe recovery from the parasitic attack. These findings show that the leaf of A. polycarpa can also be used to treat malaria.