Purifol Mechanism of Action

Folic acid is a member of the Vitamin B group. Folic acid is reduced in the body to tetrahydrofolate, which is a coenzyme for various metabolic processes including the synthesis of purine and pyrimidine nucleotides, and hence in the synthesis of DNA; it is also involved in some amino-acid conversions, and in the formation and utilization of formate. Deficiency, which can result in megaloblastic anemia, develops when the dietary intake is inadequate, as in malnutrition, from malabsorption, from increased utilization as in pregnancy or conditions such as hemolytic anemia, and as a result of the administration of folate antagonists and other drugs which interfere with normal folate metabolism.
Folic acid is absorbed mainly from the proximal part of the small intestine. The naturally occurring folate polyglutamates are largely deconjugated and reduced prior to absorption. It is the 5-methyltetrahydrofolate which appears in the portal circulation, where it is extensively bound to plasma proteins.
Folic acid is rapidly absorbed from normal diets and is distributed in body tissues. The principal storage site is the liver; it is also actively concentrated in the cerebrospinal fluid. There is an enterohepatic circulation for folate; about 4 to 5 mcg is excreted in the urine daily. Administration of larger doses of folic acid leads to proportionately more of the vitamin being excreted in the urine. Folate is distributed into breast milk.