Studies on the Effects of Methanol Extract of Vitex Doniana leaves on Plasmodium Berghei- Infected Mice

Abstract

Malaria caused by plasmodium parasite is one of the leading infectious diseases in the tropics including Nigeria. Efforts are on to developing more potent antimalarials from plant sources that will be cheaper, without adverse effects, readily available and will be able to replace existing antimalarials that are already facing resistance by plasmodium. Vitex donianais a medicinal plant used in many part of Nigeria for the treatment of malaria and other diseases. This work was set out to investigate the in vivo antiplasmodial effects and some biochemical evaluations of the methanol extract of Vitex doniana leaves in mice. The preliminary qualitative and quantitative analyses of the methanol extract of V. doniana leaves revealed the presence of steroids, carbohydrates, glycosides and acidic compound in relative amount while alkaloids, proteins and flavonoids at moderate level. Phenolics, terpenoids and tannin were present in high amount while saponins were not detected. The results of the quantitative phytochemical constituents of the leaves extracts constitute respectively: alkaloids (433.22± 7.51 mg/100g), flavonoids (302.06 ± 6.21 mg/100g), tannins (1039.60± 181.43 mg/100g), steroids (2.65± 0.08 mg/100g), protein (406.19 + 19.97), terpenoids (1055.87 ± 140.44 mg/100g), carbohydrate (29.93 + 7.23 mg/100g), total phenolics (1806.45± 234.18 mg/100g) and glycosides (5.138 + 0.17 mg/100g). The acute toxicity test of the extract showed no toxicity up to 5000 mg/kg body weight. The animals were successfully passaged with Plasmodiumberghei collected from already infected mice. The result of this study revealed that there was a reduction in the percentage parasitaemia of the treated mice when compared to the untreated animals. In this study, the lipid peroxidation product, Malondiadehyde (MDA) concentration of the treated groups decreased significantly (p < 0.05) when compared to the untreated animals. The levels of antioxidants superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) showed a significant(p < 0.05) increase in the treated groups when compared to untreated group (group 2). GSH of the treated groups 4 and 6 was found to be significantly (p<0.05) higher than the untreated group (group 2). The results from the haematological parameters showed that the extract significantly (p < 0.05) increased the RBC count, PCV count and Hb concentration in the treated groups compared to the untreated group (group 2). White blood cell count in the treated groups were found to be significantly (p < 0.05) lower compared to the untreated animals. Activities of liver marker enzymes such as ALP, AST and ALT significantly(p < 0.05) decreased in all the treated groups when compared to the untreated group. The result of this study also revealed that there was a significant (p < 0.05) decrease in total bilirubin at highest dosage compared to the untreated animals (group 2). The kidney function assessment showed that urea was found to be significantly (p < 0.05) lower in the test groups 4 and 6 than untreated group. There was also a significant (p < 0.05) decrease in the creatinine level of the treated animals compared to the untreated animals. Also, the result of serum electrolyte assessment showed that sodium and potassium were found to be significantly (p < 0.05) higher in the test groups compared to the untreated group. There was a significant (p < 0.05) increase in cholesterol, LDL, HDL and triacylglycerol concentrations in the treated groups compared to the untreated animals. The result of this study showed that V. doniana methanol leaf extract possesses antimalarial effects, which supports the claims in different parts of the country and beyond, that the plant is used in the treatment of malaria and may therefore offer a potential drug source for development of a safe, effective and affordable antimalarial. This could be attributed to the presence of some phytochemicals in the plant known to have antimalarial properties. The present study also suggests that the plant possess antioxidant properties which could fight the free radicals in the system and also has hepatoprotective, anti-anaemic and nephroprotective properties.