Repurposing the Open Access Malaria Box To Discover Potent Inhibitors of Toxoplasma gondii and Entamoeba histolytica

Abstract

ABSTRACTToxoplasmosis and amebiasis are important public health concerns worldwide. The drugs currently available to control these diseases have proven limitations. Therefore, innovative approaches should be adopted to identify and develop new leads from novel scaffolds exhibiting novel modes of action. In this paper, we describe results from the screening of compounds in the Medicines for Malaria Venture (MMV) open access Malaria Box in a search for new anti-Toxoplasmaand anti-Entamoebaagents. Standardin vitrophenotypic screening procedures were adopted to assess their biological activities. Seven anti-Toxoplasmacompounds with a 50% inhibitory concentration (IC50) of <5 μM and selectivity indexes (SI) of >6 were identified. The most interesting compound was MMV007791, a piperazine acetamide, which has an IC50of 0.19 μM and a selectivity index of >157. Also, we identified two compounds, MMV666600 and MMV006861, with modest activities againstEntamoeba histolytica, with IC50s of 10.66 μM and 15.58 μM, respectively. The anti-Toxoplasmacompounds identified in this study belong to scaffold types different from those of currently used drugs, underscoring their novelty and potential as starting points for the development of new antitoxoplasmosis drugs with novel modes of action.