Evaluation of Phytochemical Composition and Antimicrobial Activities of Terminalia avicennoides, Terminalia macroptera, and Argemone mexicana Used as Traditional Medicine in Burkina Faso

Aims: The objective of this study was to evaluate the phytochemical composition and antimicrobial activities of Terminalia avicennoides, Terminalia macroptera, and Argemone mexicana, three plants used in traditional medicine in Burkina Faso. Study Design: This work is experimental research aiming to produce scientific information on the effectiveness of these plants in the treatment of malaria, bacterial and fungal diseases. Place and Duration of Study: The Pharmacognosy Laboratory at the National Center for Training and Research on Malaria (CNRFP) in Ouagadougou (Burkina Faso) served as the framework for carrying out research activities from July 25, 2022 to April 24, 2023. Methodology: Ethanolic and hydroethanolic extracts were prepared from the leaves of T. avicennoides, the roots of T. macroptera, and the aerial parts of A. mexicana. After qualitative screening, the total phenolic, flavonoid, and flavonol contents were determined. Antiplasmodial activity was tested in vitro on the 3D7 strain of Plasmodium falciparum. Antimicrobial activity was evaluated against six bacteria and a strain of Candida albicans. The cytotoxicity of the extracts was measured by a hemolysis test. Results: The presence of alkaloids, flavonoids, tannins, and quinones has been confirmed in the extracts except the saponins were not found in the ethanolic extract of three plants. The ethanolic extract of A. mexicana showed excellent antiplasmodial activity (IC₅₀ = 2.797 ± 0.54 µg/mL), followed by that of T. avicennoides (IC₅₀ = 3.013 ± 0.22 µg/mL). However, extracts of A. mexicana were inactive against all microbial strains tested. Extracts of T. avicennoides showed the best antibacterial activity, particularly against Staphylococcus epidermidis (17 ± 1.77 mm). All extracts showed very low hemolytic toxicity. Conclusion: These results validate the traditional use of these plants. Argemone mexicana is a promising source for new antimalarial drugs, while Terminalia avicennoides shows great potential for the development of antibacterial therapies.