Ethnopharmacology and malaria in Africa

According to the last World Malaria Report [1], there were 584 000 deaths for 198 millions malaria cases worldwide in 2013. Particularly, the disease caused an estimated 437 000 African children died before their fifth birthday, still in 2013. Malaria is caused by a parasite, Plasmodium sp. and transmitted by Anopheles mosquitoes. The problem of parasite resistance towards common available medicines such as chloroquine, mefloquine, quinine, is increasing. In this context, the vegetal kingdom remains the main source of pharmacologically active compounds against this parasitic infection as attested by the famous quinine, isolated from Cinchona sp., artemisinin extracted from Artemisia annua and also atovaquone derived from lapachol found in several Bignoniaceae. All these substances are related to plants with traditional use against fever and malaria. Beside these well-known examples, various new antiplasmodial compounds are frequently discovered from Nature, particularly following an ethnopharmacological approach, as reviewed by several authors in recent years [2-6]. Then, the pharmacological and phytochemical study of plants from traditional pharmacopoeias can be of first interest not only to discover new antimalarial “lead compounds”, but also to valorize local vegetal species whose efficacy and safety would have been demonstrated in laboratory and clinical investigations [7]. As demonstrated in several works from Willcox [8], better knowledge of plants from traditional pharmacopoeias and local valorization of validated traditional remedies in Improved Traditional Medicine (ITM) could allow the access to effective, standardized, available and affordable therapeutics for management of malaria by local populations.
After this introductive section, the second part of the talk will be dedicated to the presentation of some results obtained in Liège with Dicoma tomentosa from Burkina-Faso [9], Strychnos icaja from Cameroun [10] and Terminalia mollis from Rwanda [11].
1. WHO, World Malaria Report 2014, December 2014, Geneva (http://www.who.int/malaria/publications/world_malaria_report_2014/en/).
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3. Bero J, Frédérich M, Quetin-Leclercq J : Antimalarial compounds isolated from plants used in traditional medicine. Journal of Pharmacy and Pharmacology 2009, 61:1401–1433.
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9. Jansen, O., Tits, M., Angenot, L., Nicolas, J.-P., De Mol, P., Nikiema, J.-B., & Frédérich, M : Anti-plasmodial activity of Dicoma tomentosa (Asteraceae) and identification of urospermal A-15-O-acetate as the main active compound. Malaria Journal 2012, 11, 289.
10. Tchinda, A. T., Jansen, O., Nyemb, J.-N., Tits, M., Dive, G., Angenot, L., & Frédérich, M. Strychnobaillonine, an unsymmetrical bisindole alkaloid with an unprecedented skeleton from Strychnos icaja roots. Journal of Natural Products 2014, 77(4), 1078–82.
11. Muganga, R., Angenot, L., Tits, M., & Frédérich, M : In vitro and in vivo antiplasmodial activity of three Rwandan medicinal plants and identification of their active compounds. Planta Medica 2013, 80(6), 482-489.