Screen of traditional soup broths with reported antipyretic activity towards the discovery of potential antimalarials

OBJECTIVE: The global impact of artemisinin-based combination therapies on malaria-associated mortality and their origins in ancient Chinese medicine has heightened interest in the natural discovery of future antimalarials. METHODS: A double-blind study to identify potential ingredients with antimalarial activity from traditional remedies with reported antipyretic properties. Recipes of clear broths, passed down by tradition in families of diverse ethnic origin, were sourced by school children. Broths were then tested for their ability to arrest malaria parasite asexual growth or sexual stage development in vitro. Clear broth extract was incubated with in vitro cultures of Plasmodium falciparum asexual or mature sexual stage cultures and assayed for parasite viability after 72 hours. RESULTS: Of the 56 broths tested, 5 were found to give >50% in vitro growth inhibition against P. falciparum asexual blood stages, with 2 having comparable inhibition to that seen with dihydroartemisinin, a leading antimalarial. Four other broths were found to have >50% transmission blocking activity, preventing male parasite sexual stage development. After unblinding, two active broths were found to be from siblings from different classes, who had brought in the same vegetarian soup, demonstrating assay robustness. CONCLUSIONS: This screening approach succeeded in finding broths with activity against malaria parasite in vitro growth, arising from complex vegetable and/or meat-based broths. This represented a successful child education exercise, in teaching about the interface between natural remedies, traditional medicine and evidence-based drug discovery.