Comparison of phytochemical profiles and antimalarial activities of Artemisia afra plant collected from five countries in Africa

Malaria is one of the most dangerous and deadly tropical disease in Africa affecting millions of individuals yearly. It is a major global public health problem, with an alarming spread of parasite resistance to the ACTs drugs. This situation explain the urge to discover new antimalarial compounds. Indigenous species to Africa and traditionally used for years by traditional healers, Artemisia afra is a big source for new antimalarial drugs. Aerial parts of Artemisia afra plant collected from South Africa, Kenya, Tanzania, Burundi and Senegal were each extracted with solvents of different polarity (hexane, dichloromethane, ethanol, and water), and the different extracts were then screened and compared for their antimalarial activities against two Plasmodium falciparum strains W2 (CQ resistant) and D6 (CQ sensitive); and also compared for their total phenols, flavonoids content and antioxidant activities. Phytochemical screening of the extracts revealed the presence of terpenoids, alkaloids, tannins, saponins and cardiac glycosides. Ethanolic extract of Artemisia afra collected from Burundi was found to have the highest concentration of phenols (606.9449 mg GAE/g of extract) and flavonoids (242.4745 mg Rutin/g of extract) and also exhibited the highest antioxidant activity (IC50 = 3.12 μg/mL) compare to the others. Total phenols and total flavonoids were found to correlate with the antioxidant activity. Artemisia afra collected from Burundi also showed the highest antimalarial activity compare to the other extracts, the hexane extract of A. afra from Burundi have the highest (IC50 = 0.71μ g/ml for W2 and IC50 = 3.18 μg/ml for D6); following by the ethanolic extract (IC50 = 2.66 μg/ml for W2 and 7.84 μg/ml for D6; then the dichloromethane extract (IC50 = 3.04 μg/ml for W2 and IC50 = 7.92 μg/ml for D6). Comparison of the five A. afra plants collected from South Africa, Kenya, Tanzania, Burundi and Senegal showed that the extracts from Burundi had the highest total content of phenols and flavonoids and also the highest level of antimalarial activity compared to the other plant extracts.