5-FOA(5-Fluoroorotic acid ) has become a valuable tool for research in the field of molecular genetics. It has been employed in the selection of resistant strains of Saccharomyces cerevisiae that possess a mutant URA3 gene which renders them orotidine-5'-phosphate decarboxylase deficient. 5-FOA is coverted to 5-fluorouridine monophosphate (5-FUMP) in yeast cells, which can become incorporated into RNA or metabolized to the highly toxic 5-fluoro-2’-deoxyuridine monophosphate (5-FdUMP). 5-FdUMP is a potent inhibitor of thymidylate synthase (TS), causing the cessation of DNA synthesis. More recently, 5-FOA has been shown to possess potent antimalarial activity against both chloroquine-susceptible and chloroquine-resistant clones of Plasmodium falciparum. Studies indicate that TS is the primary target of 5-FOA in malarial parasites. The combination of 5-FOA and uracil has been effective in treating mice infected with Plasmodium yoelli. 5-FOA may also have potential in the treatment of human malarial infections when used in combination with other agents.
