Oral acute toxicity and antimalarial potentials of aqueous and methanolic extracts of roots, leaves and stem of Dictyandra arborescens (Welw.) on Plasmodium berghei infected mice

Abstract

Abstract Background Malaria is one of the tropical diseases of universal concern particularly with continuous appearance of resistant strains of P.falciparum . This calls for continous screening of traditional plants such that new and effective antimalarial agents will be developed. This study therefore explored the oral acute toxicity and antimalarial potentials of aqueous and methanolic extracts of roots, leaves and stem of Dictyandra arborescens on Plasmodium berghei infected mice. Results No mortality was recorded in any of the experimental animal groups even at the highest tested dose (5000 mg/kg b.wt) of the extract after monitoring them for 4hrs and subsequently for 7 days. Out of the six extracts, methanolic extracts of the roots and leaves exhibited more antimalarial activity than others. A significant difference (P < 0.05) was statistically observed in the parasite count of groups that received methanol extracts of roots and leaves of D. arborescens . This observation was made when these two extracts were compared with other groups as well as the negative control. However, activity of the standard antimalarial drug (artesunate) was higher (p˂0.05) than those of the extracts. Phytochemicals such as tannins, alkaloids, saponins, terpenoids, flavonoids etc. were present in the extracts in varying quantities. GC–MS analysis of methanol extract of the root of this plant showed different chemical compounds. Conclusion Administration of aqueous and methanol extracts of roots, leaves and stem of D. arborescens in mice is not harmful at any dose less than or equal to 5000 mg/kg. Methanol extracts exhibited more antimalarial activity than aqueous extracts suggesting that antimalarial activity of the plant parts could be affected by the solvent used for extraction and antimalarial activity may be more in a particular part of a plant. The presence of different bioactive compounds identified in phytochemical and GC–MS analysis could be the fundamental scientific evidence for the antimalarial activity exhibited by this plant especially in the root.