The Antimalarial Potential of Three Ghanaian Medicinal Plants

Objective: Malaria is a major public health problem in Ghana and many indigenes, especially those in rural areas, resort to the use of medicinal plants to treat the disease. The plants: Persea americana Mill. (Lauraceae), Theobroma cacao L. (Malvaceae) and Tridax procumbens (L.) L. (Compositae) are used solely or in combination with other medicinal plants to manage malaria and its associated conditions. The leaves of the plants which are normally the main parts employed, were studied for their phytochemistry and antiplasmodial activity to establish their chemical profile and verify the antimalarial claim. Methods: Plant materials were subjected to basic phytochemical screening to identify the major secondary metabolites. The aqueous extracts were evaluated against chloroquine-sensitive 3D7 P. falciparum and chloroquine-resistant W2 P. falciparum strains, using the fluorescence-based SYBR® green I method to determine their antiplasmodial activity. Results: Basic phytochemical screening of the leaves revealed the presence of tannins, flavonoids and alkaloids in all three plant materials. T. cacao and P. americana, in addition, contained purine base alkaloids, triterpenoids including saponins. The aqueous extracts of the leaves showed antiplasmodial activity against the chloroquine-sensitive 3D7 P. falciparum (9.50 ± 1.38 ≤ IC50 ≤ 10.15 ± 0.45 µg/mL) and against chloroquine-resistant W2 P. falciparum strains (6.40 ± 1.94 ≤ IC50 ≤ 44.94 ± 1.12 µg/mL). The aqueous extract of T. cacao was the most active and was more active against W2 than 3D7 P. falciparum. Only T. procumbens displayed cytotoxicity (CC50