Abstract:
The purpose of this study was to evaluate in vivo antiplasmodial effect of ethanolic extracts of Alstonia boonei leaves and Petersianthus macrocarpus stem bark and compare their antiplasmodial effects with chloroquine phosphate, a standard antimalarial. Phytochemical analysis of the extracts was carried out using standard procedures. The oral acute toxicity was evaluated in mice using modified Lorke s method and the in vivo anti-plasmodial effect against early infection and curative effect against established infection were studied in chloroquinesensitive Plasmodium berghei berghei NK65-infected mice. Results of the phytochemical tests showed relative abundance of alkaloids, glycosides, tannins, resins, steroids, flavonoids, terpenoids and saponins in the extracts. The oral median lethal dose of the extracts in mice was determined to be 3,807.9 mg/kg body weight for P. microcarpus and >5000 mg/kg body weight for A. boonei. Comparatively, chloroquine (5 mg/kg) gave the same chemo-suppressive effect as 200 mg/kg b. wt. of each of the extract and also exhibited similar curative effect as 400 mg/kg b. wt. p.o. of each of the extract, which were significantly (p 0.05) greater than that of negative control (5 mL/kg distilled water) . Overall, the antimalarial effects in the curative and suppressive tests were higher in A. boonei than P. macrocarpus. Results of this study has shown that ethanolic extracts of A. boonei leaves and P. microcarpus stem bark possess potent antimalarial effects and could therefore offer potential for safe, effective and affordable antimalarial phytomedicines. Further experiments will be required to identify the active constituent(s) responsible for the observed antimalarial effects and their mechanism(s) of action. Malaria is undoubtedly the single most destructive and dangerous infectious disease in the developing world. Attempts at eradicating the disease with insecticides and chemotherapeutic drugs failed because of the emergence of drug-resistant parasites and female Anopheles mosquitoes that are resistant to insecticides. Herbal medicines are widely used due to their therapeutic efficacy coupled with least side effects, which initiate the scientific research regarding the antimalarial activity. A. boonei and P. macrocarpus are medicinal plants widely used in folkloric medicine in Nigeria in the management of acute malaria and other ailments. The present study will help the industry to develop herbal medicine as alternatives to synthetic and semi-synthetic agents in the treatment of malaria with less likelihood of resistance and at a lower cost.
