Antimalarial Efficacy and Toxicological Assessment of Extracts of Some Ghanaian Medicinal Plants

Abstract

The economic costs associated with morbidity and mortality due to malaria and malaria associated complications in many sub-Saharan countries and other malaria endemic regions of the world are huge. Reports of emergence of parasite resistance to current malaria drugs have complicated malaria treatment and require the development of new therapeutic agents. The folkloric use of medicinal plants for the management of malaria is well documented. This work evaluated the antiplasmodial activities and toxicity of some medicinal plants used to treat malaria and malaria-like symptoms in Ghana. Plant extracts were obtained by cold maceration in 70% ethanol. Antiplasmodial efficacies were assessed <i>in vitro</i> against 3 strains of <i>Plasmodium falciparum</i> strains (FCM, W2, and CAM06) and <i>in vivo</i> via the 4-day suppressive test in <i>Plasmodium berghei</i> infected mice. Cytotoxicity and acute toxicity were assessed in mammalian cells and mice, respectively. All extracts were active against at least one of the <i>Plasmodium falciparum</i> strains in <i>in vitro</i> evaluations with IC₅₀'s in the range of 4-116 <i>μ</i>g/mL, whereas <i>Bidens pilosa</i> extracts, with a chemosuppression rate of 75%, was the most active plant in the <i>in vivo</i> experiments. All plant extracts displayed very weak to no cytotoxicity against the mammalian cell line used and exhibited very good selectivity towards the <i>Plasmodium</i> parasites. <i>Syzygium guineense</i> and <i>Parinari congensis</i> extracts were the most toxic in the acute toxicity tests. Altogether, the results indicate that the medicinal plants do possess impressive antiplasmodial properties and provide scientific basis for their use in traditional herbal medicine.