Natural Products from Plants as Drug Candidates and Lead Compounds Against Leishmaniasis and Trypanosomiasis

Millions of people in the developing world are affected by diseases caused by the kinetoplastid parasites: the leishmaniases, African trypanosomiasis, and Chagas disease. In many cases the drugs employed for treatment are toxic, marginally effective, given by injection, and/or compromised by the development of resistance. Since safe, effective, and affordable chemotherapeutic agents for leishmaniasis and trypanosomiasis are clearly needed, the identification of new antikinetoplastid drug candidates should be an urgent priority. Numerous plant-derived natural products from different structural classes have been investigated as antileishmanial and antitrypanosomal candidates, including various alkaloids, terpenoids, flavonoids, and quinonoids. This review outlines the antikinetoplastid activities of plant-derived natural products reported in the literature and also provides an overview of mechanistic studies that have been conducted with these compounds. Given the activities of these agents and their diverse range of effects on parasite biology, natural products are a potentially rich source of drug candidates and leads against leishmaniasis and trypanosomiasis.