Pentafluoro‐3‐hydroxy‐pent‐2‐en‐1‐ones Potently Inhibit FNT‐Type Lactate Transporters from all Five Human‐Pathogenic Plasmodium Species

The protozoan parasite Plasmodium falciparum causes the most severe and prevailing form of malaria in sub‐Saharan Africa. Previously, we identified the plasmodial lactate transporter, PfFNT, a member of the microbial formate–nitrite transporter family, as a novel antimalarial drug target. With the pentafluoro‐3‐hydroxy‐pent‐2‐en‐1‐ones, we discovered PfFNT inhibitors that potently kill P. falciparum parasites in vitro. Four additional human‐pathogenic Plasmodium species require attention, that is, P. vivax, most prevalent outside of Africa, and the regional P. malariae, P. ovale and P. knowlesi. Herein, we show that the plasmodial FNT variants are highly similar in terms of protein sequence and functionality. The FNTs from all human‐pathogenic plasmodia and the rodent malaria parasite were efficiently inhibited by pentafluoro‐3‐hydroxy‐pent‐2‐en‐1‐ones. We further established a phenotypic yeast‐based FNT inhibitor screen, and found very low compound cytotoxicity and monocarboxylate transporter 1 off‐target activity on human cells, particularly of the most potent FNT inhibitor BH267.meta, allowing these compounds to proceed towards animal model malaria studies. Expanding inhibition: The FNT lactate transporters of four human‐pathogenic Plasmodium species and the rodent malaria parasite have been evaluated as targets of pentafluoro‐3‐hydroxy‐pent‐2‐en‐1‐one PfFNT inhibitors. The proteins deviate only in the periphery, and are similarly susceptible to these potent small‐molecule inhibitors. The compounds exhibit high on‐target potency, minimal cytotoxicity and off‐target effects enabling translation to animal studies.