Malaysian plants with potential in vitro trypanocidal activity

Human African trypanosomiasis (HAT), caused by the protozoan parasite, Trypanosoma brucei and transmitted by the bite of tsetse flies, affects more than 60 million people in the sub-Saharan African countries. Without treatment, the disease can be fatal. Current treatment options for HAT are scarce, toxic, marginally effective, difficult to administer and compromised by the development of resistance, especially for the advanced second stage of the disease. Thus, new safe, effective, and affordable antitrypanosomal drug candidates are urgently needed. Numerous plant-derived natural products from different structural classes have been investigated for their trypanocidal activity. This review aims to provide updated information, based on published articles, on the antitrypanosomal activity of natural products from Malaysian plants investigated by researchers at the Forest Research Institute Malaysia (FRIM) and Malaysian Institute of Pharmaceuticals and Nutraceuticals (IPharm). Extracts from a total of 1273 species of plants collected from different locations in Peninsular Malaysia were evaluated for in vitro growth inhibitory activity against Trypanosoma brucei brucei (strain BS221) and T. b. rhodesiense (strain STIB 900), using assays established at the respective institutes. Several plants that have demonstrated promising trypanocidal effects will be discussed using examples of other plant-derived antitrypanosomal natural products reported in the literature to compare their activity and chemical properties.