Coumarins as Potential Antiprotozoal Agents: Biological Activities and Mechanism of Action

Since the discovery of dicoumarol (a coumarin-based anticoagulant) in 1940, coumarins have been found to possess a range of biological activities such as antimicrobial, anti-inflammatory, antioxidant, anticancer, and antiviral. The subsequent development of compounds containing a coumarin nucleus for use as potential new drug candidates has progressively grown in view of their diverse biological activities. This review addresses the structure–activity relationship of coumarin-based compounds, focusing on their potential for use as antiprotozoal agents against neglected tropical diseases which are a diverse group of illnesses that affect over one billion people globally. Most of them are caused by parasitic organisms including protozoa, helminths, and ectoparasites. Neglected tropical diseases which are caused by protozoa include human leishmaniasis, Chagas disease, American trypanosomiasis, and African trypanosomiasis, which range in severity from mild and self-curing to untreatable and fatal. This review compiles relevant information on the biological potential and possible mechanisms of action of coumarin-based compounds for use against neglected tropical diseases, including malaria, and highlights the most relevant and promising compounds. Natural, synthetic, and semi-synthetic coumarin represent prominent candidates in the search for new drugs to treat neglected tropical diseases.