Antifolate (叶酸拮抗剂)

Antifolates agents work by antagonizing (blocking) the actions of folic acid (vitamin B9). Antifolates act specifically during DNA and RNA synthesis, exerting a cytotoxic effect during the S- phase of the cell cycle. Antifolates targeting folate metabolism played a pivotal role in drug treatment of malignant, microbial, parasitic and chronic inflammatory diseases.

Folate (folic acid) cofactors are essential for the synthesis and metabolism of amino acids, consequently antifolates inhibit cell division, DNA/RNA synthesis and repair and protein synthesis. Some such as Proguanil, Pyrimethamine and Trimethoprim selectively inhibit folate's actions in microbial organisms such as bacteria, protozoa and fungi. Major antifolate enzyme targets and exemplary antifolates that target these enzymes include: dihydrofolate reductase (DHFR), thymidylate synthase (TS), GARFTase and AICARFTase.