Folic acid

Folic acid—commonly referred to as **folate** in its natural forms—is a water-soluble B-vitamin essential for the generation and maintenance of new cells. It is required for DNA and RNA synthesis through methylation reactions and plays a critical role in amino acid metabolism necessary for cell division and the maturation of blood cells. Naturally occurring folates exist in many chemical forms found in food; synthetic **folic acid** is used in fortified foods and supplements. Folic acid itself has no biological activity unless converted into active forms such as tetrahydrofolate by dihydrofolate reductase. Drugs that inhibit this enzyme—such as methotrexate—are used therapeutically to treat cancer by blocking DNA synthesis but can cause significant toxicity. Folinic acid (leucovorin) can be administered to mitigate these toxic effects without negating anticancer efficacy because it bypasses the blocked step. Deficiency of dietary folates leads to megaloblastic anemia; adequate intake is especially important during pregnancy due to its role in preventing neural tube defects.\n\n**Note:**\nFolate/folic acid is *not* itself a therapeutic target like an enzyme or receptor but rather an essential nutrient/cofactor targeted indirectly by certain drugs ("antifolates"). The term "Folate" does not refer specifically to any single protein or receptor but rather encompasses a family of related compounds with vitamin activity; thus, it does not fit standard drug-target conventions.

Other names

FolateVitamin B9FolacinPteroyl-L-glutamic acidVitamin MVitamin Bc

Antifolate drugs inhibit dihydrofolate reductase, blocking conversion of folic acid to tetrahydrofolate, thereby inhibiting DNA synthesis in rapidly dividing cells such as cancer cells.\nLeucovorin "rescue" provides reduced folates to normal cells during antifolate chemotherapy.