Abstract The genus Plasmodium is a causative protozoan of Malaria. The treatment of malaria has been since the 1970s based on the use of Artemisinin derivatives extracted from Artemisia annua. Despite the use of Artemisinin Combination Therapy to limit the emergence of the Plasmodium resistant strains, therapeutic failures still exist because of these strains. Thus, in a search for new antimalarial molecules, two medicinal plants commonly used in traditional medicine to fight malaria in Cameroon are here explored. The aim of this work was to evaluate comparatively the antiplasmodial, the cytotoxic, and the antioxidant activities of aqueous and hydroethanolic extracts of N. pobeguinii and A. annua, our reference plant. Maceration and decoction methods were used. Different classes of secondary metabolites of the crude extracts were qualitatively highlighted by phytochemical screening. The toxicity evaluation of the extracts was carried out in culture and the antiplasmodial activity of the extracts were studied and revealed by spectrophotometry. Results show that the extraction yields varied from 3.5 to 15.5%. The phytochemical screening revealed the presence of phenols, saponins, alkaloids, flavonoids in the extracts. However, the reference plant A. annua showed a better antiplasmodial IC50 activity (3.82 and 4.89 µg/mL) compared to N. pobeguinii IC50 (10.35 and 25.85 µg/mL). There was no indication of toxicity of these extracts to healthy erythrocytes and, to RAW and VERO cells. The hydroethanolic extract of A. annua leaves and the aqueous extract of N. pobeguinii barks presented very good antioxidant activities. These results justify the use of N. pobeguinii in traditional medicine; although it showed less activity compared to A. annua for the treatment of malaria. This observation warrants further investigations of N. pobeguinii barks for its use as an alternative remedy for the control of malaria.
Keywords Plasmodium, malaria, antioxidant, antiplasmodium, Nauclea pobeguinii, Artemisia annua.