ANTI-PLASMODIAL EFFECTS OF BITTER LEAF AND NEEM LEAF EXTRACTS ON PLASMODIUM BERGHEI INFECTED MICE

Abstract

Malaria remains one of the most infectious diseases, caused by protozoan parasite of the genus Plasmodium and it is the most prevalent tropical disease resulting in high morbidity with its consequent economic and social loss. Currently, the control of malaria has become gradually more complex due to the spread of drug-resistant parasites. Medicinal plants are the unquestionable source of effective antimalarial agent. The present study was designed to evaluate antiplasmodial activity of crude methanol extract and alkaloidal fractions of Vernonia amygdalina and Azadirachta indica in plasmodium berghei infected mice. The effects of ethanolic extract of Vernonia amygdalina and Azadirachta indica on body weight changes, biochemical and haematological parameters were assessed. Also, the phytochemical constituent of the plants was analysed for the presence of bioactive metabolites and the acute lethal doses were determined using standard procedure. A rodent malaria parasite, Plasmodium berghei, was used to inoculate healthy Swiss Albino mice of both sexes aged 6–8 weeks and weight 28–35 g. Crude methanol extract and the alkaloidal fractions were administered at different doses 150, 300 and 600 mg/kg body weight. Parameters, including parasitemia, body weight, and packed cell volume were then determined using standard tests. The LD50 of the plant was extrapolated to be above 5000 mg/kg body weight. The results indicated the presence of phytochemicals including flavonoids, phenols, tanins, and alkaloids. The Methanol extract of V. amygdalina and A. indica leaves exhibited very good antiplasmodial activity as they had exhibited parasitaemia suppression of 52.23 ± 2.34 and 90.21 ± 3.94% at concentrations of 150-600 mg/kg, respectively. The body weight of all the experimental groups show initial decreases after P. berghei infection. However, groups of mice treated with crude and alkaloidal fraction of V. amygdalina and A. indica shows a significant (p<0.05) improvement in the body weight after treatments. In addition, crude extract from both plants exhibited more pronounced positive effect on the weight gain of the animals than their respective alkaloidal fraction. There was a dose dependent increase in the hematological indices when compared with the untreated control. The alkaloidal fractions of these plants show relatively low antiplasmodial activities compare to the crude extract, thus indicating a synergetic activities of phytochemicals component of each plants. Therefore, these plants can be developed as a new drug for the treatment of malaria.