Folic acid

Absorption

Folic acid is absorbed rapidly from the small intestine, primarily from the proximal portion. Naturally occurring conjugated folates are reduced enzymatically to folic acid in the gastrointestinal tract prior to absorption. Folic acid appears in the plasma approximately 15 to 30 minutes after an oral dose; peak levels are generally reached within 1 hour.

Toxicity

IPR-MUS LD50 85 mg/kg,IVN-GPG LD50 120 mg/kg, IVN-MUS LD50 239 mg/kg, IVN-RAT LD50 500 mg/kg, IVN-RBT LD50 410 mg/kg

Description

Folic acid is an essential B vitamin. It is converted to folate in vivo, which is a necessary cofactor for a variety of biological processes, including nucleotide synthesis and, thus, DNA synthesis and repair, among others. A deficiency in dietary folic acid can lead to a range of developmental and cognitive disorders, most prominently neural tube defects and congenital heart defects.

Description

Folic acid, or vitamin B9, is essential for many bodily functions, including DNA synthesis, repair, and methylation. In 1941, H. K. Mitchell and co-workers isolated it by extracting 4 tons of spinach. In 1948, much work on folic acid was published, including the?determination of its structure?by J. H. Mowat and colleagues. Closely related methotrexate is an “antifolate” that can be used to treat cancer, but it has toxic side effects. It is also used to treat some autoimmune diseases and to terminate pregnancy. The more recent, less toxic pemetrexed, another antifolate chemotherapy drug, was approved by the FDA in 2004.

The Uses of Folic acid

folic acid is generally used as an emollient. In vitro and in vivo skin studies now indicate its capacity to aid in DnA synthesis and repair, promote cellular turnover, reduce wrinkles, and promote skin firmness. There is some indication that folic acid may also protect DnA from uV-induced damage. Folic acid is a member of the vitamin B complex and is naturally occurring in leafy greens.

What are the applications of Application

Folic Acid is an important cofactor in the transfer of one-carbon moieties plays role in formation of S-adenosyl met

Indications

Folic acid is indicated for the treatment of folic acid deficiency, megaloblastic anemia, and in anemias of nutritional origins, pregnancy, infancy, or childhood.

Background

Folic acid, also known as folate or Vitamin B9, is a member of the B vitamin family and an essential cofactor for enzymes involved in DNA and RNA synthesis. More specifically, folic acid is required by the body for the synthesis of purines, pyrimidines, and methionine before incorporation into DNA or protein. Folic acid is particularly important during phases of rapid cell division, such as infancy, pregnancy, and erythropoiesis, and plays a protective factor in the development of cancer. As humans are unable to synthesize folic acid endogenously, diet and supplementation is necessary to prevent deficiencies. For example, folic acid is present in green vegetables, beans, avocado, and some fruits.
In order to function within the body, folic acid must first be reduced by the enzyme dihydrofolate reductase (DHFR) into the cofactors dihydrofolate (DHF) and tetrahydrofolate (THF). This important pathway, which is required for de novo synthesis of nucleic acids and amino acids, is disrupted by anti-metabolite therapies such as Methotrexate as they function as DHFR inhibitors to prevent DNA synthesis in rapidly dividing cells, and therefore prevent the formation of DHF and THF. When used in high doses such as for cancer therapy, or in low doses such as for Rheumatoid Arthritis or psoriasis, Methotrexate impedes the body's ability to create folic acid. This results in a deficiency of coenzymes and a resultant buildup of toxic substances that are responsible for numerous adverse side effects. As a result, supplementation with 1-5mg of folic acid is recommended to prevent deficiency and a number of side effects associated with MTX therapy including mouth ulcers and gastrointestinal irritation. Leucovorin (also known as folinic acid) supplementation is typically used for high-dose MTX regimens for the treatment of cancer. Levoleucovorin and leucovorin are analogs of tetrahydrofolate (THF) and are able to bypass DHFR reduction to act as a cellular replacement for the co-factor THF.
There are also several antiepileptic drugs (AEDs) that are associated with reduced serum and red blood cell folate, including Carbamazepine (CBZ), Phenytoin (PHT), or barbiturates. Folic acid is therefore often provided as supplementation to individuals using these medications, particularly to women of child-bearing age.
Inadequate folate levels can result in a number of health concerns including cardiovascular disease, megaloblastic anemias, cognitive deficiencies, and neural tube defects (NTDs). Folic acid is typically supplemented during pregnancy to prevent the development of NTDs and in individuals with alcoholism to prevent the development of neurological disorders, for example.

Pharmacokinetics

Folic acid is a water-soluble B-complex vitamin found in foods such as liver, kidney, yeast, and leafy, green vegetables. Also known as folate or Vitamin B9, folic acid is an essential cofactor for enzymes involved in DNA and RNA synthesis. More specifically, folic acid is required by the body for the synthesis of purines, pyrimidines, and methionine before incorporation into DNA or protein. Folic acid is the precursor of tetrahydrofolic acid, which is involved as a cofactor for transformylation reactions in the biosynthesis of purines and thymidylates of nucleic acids. Impairment of thymidylate synthesis in patients with folic acid deficiency is thought to account for the defective deoxyribonucleic acid (DNA) synthesis that leads to megaloblast formation and megaloblastic and macrocytic anemias. Folic acid is particularly important during phases of rapid cell division, such as infancy, pregnancy, and erythropoiesis, and plays a protective factor in the development of cancer. As humans are unable to synthesize folic acid endogenously, diet and supplementation is necessary to prevent deficiencies. In order to function properly within the body, folic acid must first be reduced by the enzyme dihydrofolate reductase (DHFR) into the cofactors dihydrofolate (DHF) and tetrahydrofolate (THF). This important pathway, which is required for de novo synthesis of nucleic acids and amino acids, is disrupted by anti-metabolite therapies such as Methotrexate as they function as DHFR inhibitors to prevent DNA synthesis in rapidly dividing cells, and therefore prevent the formation of DHF and THF.
In general, folate serum levels below 5 ng/mL indicate folate deficiency, and levels below 2 ng/mL usually result in megaloblastic anemia.

Metabolism

Folic acid is metabolized in the liver into the cofactors dihydrofolate (DHF) and tetrahydrofolate (THF) by the enzyme dihydrofolate reductase (DHFR).