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, 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. It is essential for many bodily functions, including DNA synthesis, repair, and methylation. 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.

Description

In the 1930s, brewer’s yeast was found to prevent anemia. Folic acid was later discovered to be the nutrient responsible for this effect and was purified in 1941 by Mitchell and coworkers (Mitchell et al., 1941). Folate is needed for biosynthesis of purines and thymidine for DNA and RNA synthesis in all cells. It is also involved in metabolism of some of the amino acids needed for protein synthesis, especially the conversions of serine to glycine and homocysteine to methionine. This makes the nutrient especially important during periods of rapid cell division, such as in pregnancy. Folate is also involved in transfer of one-carbon groups for methylation reactions. The role of folate in cell division was capitalized upon in the synthesis of aminopterin, a folate antagonist, which was one of the first anticancer drugs produced.

Chemical properties

orange to yellow crystalline powder

Physical properties

The folates include a large number of chemically related species, each differing with respect to the various substituents possible at three sites on the pteroylglutamic acid basic structure. More than 170 different folates are theoretically possible. Not all of these occur in nature; but it has been estimated that as many as 100 different forms are found in animals. The folates from most natural sources usually have a single carbon unit at N-5 and/or N-10; these forms participate in the metabolism of the single-carbon pool.
Folic acid (pteroylmonoglutamic acid) is an orange-yellow crystalline substance that is soluble in water but insoluble in ethanol or less polar organic solvents. It is unstable to light, to acidic or alkaline conditions, to reducing agents, and, except in dry form, to heat. It is reduced in vivo enzymatically (or in vitro with a reductant such as dithionite) first to 7,8-dihydrofolic acid (FH2) and then to FH4; both of these compounds are unstable in aerobic environments and must be protected by the pres ence of an antioxidant (e.g., ascorbic acid, 2-mer
Two derivatives of folic acid, each having an amino group in the place of the hydroxyl at C-4, are folate antagonists of biomedical use: aminopterin (4-aminofolic acid) and methotrexate (4-amino-N10-methylfolic acid). Aminopterin is used as a rodenticide; methotrexate is an antineoplastic agent.

Originator

Folvite, Lederle, US ,1946

Occurrence

Synthetic

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.

The Uses of Folic acid

A vitamin needed to synthesize DNA, conduct DNA repair and methylate DNA, it also acts as a cofactor in biological reactions involving folate.

The Uses of Folic acid

hematopoietic vitamin

The Uses of Folic acid

Literature tends to indicate that B vitamins cannot pass through the layers of the skin and, therefore, are of no value in the skin surface. Current experiments demonstrate, however, that vitamin B2 acts as a chemical reaction accelerator, enhancing the performance of tyrosine derivatives in suntan-accelerating preparations.

The Uses of Folic acid

Folic Acid is a water-soluble b-complex vitamin that aids in the for- mation of red blood cells, prevents certain anemias, and is essential in normal metabolism. high-temperature processing affects its sta- bility. it is best stored at lower than room temperatures. it is also termed folacin. it is found in liver, nuts, and green vegetables.

Indications

Inadequate folate levels can result in several 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. Folic acid is indicated for treating folic acid deficiency, megaloblastic anemia, and anemias of nutritional origins during pregnancy, infancy, or childhood.

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

Definition

ChEBI: An N-acyl-amino acid that is a form of the water-soluble vitamin B9. Its biologically active forms (tetrahydrofolate and others) are essential for nucleotide biosynthesis and homocysteine remethylation.

Manufacturing Process

The following description is taken from US Patent 2,956,057.
100 grams of 1,3,3-trichloroacetone are heated on a boiling water bath and 95 grams of bromine are added thereto in drops while being stirred and the stirring is continued for about 1 hour. The resulting reaction solution is distilled under reduced pressure. 115 grams of 1-bromo-1,3,3- trichloroacetone are obtained having a boiling point of 85° to 95°C/17 mm (Hg).
For the preparation of the hydrate, 100 grams of water are added to 100 grams of 1bromo-1,3,3-trichloroacetone, which is agitated and cooled. A white scaly crystal of hydrate of 1-bromo-1,3,3-trichloroacetone is obtained (100 grams), having a melting point of 52° to 53°C.
8.9 grams of 2,4,5-triamino-6-hydroxypyrimidine hydrochloride and 8 grams of p-aminobenzoylglutamic acid are dissolved in 400 cc warm water, which is cooled at 35° to 27°C and adjusted to pH 4 by using 20% caustic soda solution. To this solution was simultaneously added dropwise a solution obtained by dissolving 13.4 grams of 1-bromo-1,3,3-trichloroacetone hydrate in 90 cc of 50% methanol and 24 grams of 35% aqueous sodium bisulfite solution over a period of approximately 2 hours. During this period, in order to maintain the pH value of the reaction solution at 4 to 5, 20% caustic soda solution is added from time to time. The precipitate, formed by stirring for 5 hours after dropping was finished, is filtered, and the filtrated precipitate is refined; 5.6 grams of pure pteroylglutamic acid is obtained.

Therapeutic Function

Treatment of B vitamin (folacin) deficiency

General Description

Odorless orange-yellow needles or platelets. Darkens and chars from approximately 482°F.

Air & Water Reactions

Insoluble in water. Aqueous solutions have pHs of 4.0-4.8.

Reactivity Profile

Acid solutions of Folic acid are sensitive to heat, but towards neutrality, stability progressively increases. Solutions are inactivated by ultraviolet light and alkaline solutions are sensitive to oxidation. Folic acid is also inactivated by light. Folic acid is incompatible with oxidizing agents, reducing agents and heavy metal ions.

Fire Hazard

Flash point data for Folic acid are not available; however, Folic acid is probably combustible.

Biochem/physiol Actions

A nutritional delivery form of folate. Folic acid and its derivatives are essential mediators of one-carbon metabolism within cells.

Pharmacokinetics

Folic acid (pteroylglutamic acid; FA) occurs largely as polyglutamates in food and must be hydrolyzed to the monoglutamate form for absorption, a reaction mediated by folate conjugase on the brush border of enterocytes in the proximal small intestine. Absorption of the mono glutamate form occurs in part by a saturable transport process with an acidic pH optimum via the proton-coupled folate transporter (PCFT, SLC46A1) that is expressed widely, including on the brush border membrane of the proximal intestine and renal tubule. PCFT is active only at pH 5–6, as in the microenvironment of those membranes. The Km for this system is 1–3 μM. In addition, an apparently unsaturable pathway is active when luminal concentrations of folate exceed 5–10 μM. This dual system is responsible for part of the variation in bioavailability at the extreme levels of folate intake. The bioavailability of FA was quite low after a high oral dose (F = 0.01), in contrast to a high value after intramuscular administration (F = 0.95). The plasma levels of biologically active, reduced forms of folates (THF and 5MF) were significantly increased over their basal levels after IV and IM administration to FA. The levels of these active folates did not increase after oral administration of a similar dose of FA. A 50 times higher dose was required to increase the active folates to the levels observed after IV and IM administration.

Clinical Use

Folate-deficient megaloblastic anaemia
Supplement in HD patients

Safety Profile

Poison by intraperitoneal and intravenous routes. Experimental teratogenic effects. Mutation data reported. When heated to decomposition it emits toxic fumes of NOx.

Veterinary Drugs and Treatments

Folic acid is used to treat folic acid deficiency in dogs, cats, and horses (theoretically in other animal species as well) often due to small intestinal disease. Cats with exocrine pancreatic insufficiency appear to be most at risk for folate and cobalamin deficiencies secondary to malabsorption of folic acid in the diet. Dogs with exocrine pancreatic insufficiency often are noted to have increased folate levels secondary to overgrowths of folate-synthesizing bacteria in the proximal small intestine. Chronic administration of dihydrofolate reductase inhibiting drugs such as pyrimethamine, ormetoprim or trimethoprim can potentially lead to reduced activated folic acid (tetrahydrofolic acid); folic acid supplementation is sometimes prescribed in an attempt to alleviate this situation.

Drug interactions

Potentially hazardous interactions with other drugs
Antiepileptics: reduces phenytoin, primidone and phenobarbital levels.
Cytotoxics: avoid with raltitrexed.

Mode of action

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 several 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 cofactor 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.

Metabolism

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

Metabolism

Folic acid given therapeutically enters the portal circulation largely unchanged, since it is a poor substrate for reduction by dihydrofolate reductase. It is converted to the metabolically active form 5-methyltetrahydrofolate in the plasma and liver. Folate undergoes enterohepatic circulation. Folate metabolites are eliminated in the urine and folate in excess of body requirements is excreted unchanged in the urine.

Purification Methods

If paper chromatography indicates impurities, then recrystallise it from hot H2O or from dilute acid [Walker et al. J Am Chem Soc 70 19 1948]. Impurities may be removed by repeated extraction with n-BuOH of a neutral aqueous solution of folic acid (by suspending in H2O and adding N NaOH dropwise till the solid dissolves, then adjusting the pH to ~7.0-7.5) followed by precipitation with acid, filtration, or better collected by centrifugation and recrystallised form hot H2O. [Blakley Biochem J 65 331 1975, Kalifa et al. Helv Chim Acta 6 1 2739 1978.] Chromatography on cellulose followed by filtration through charcoal has also been used to obtain pure acid. [Sakami & Knowles Science 129 274 1959.] UV: max 247 and 296nm ( 12,800 and 18,700) in H2O pH 1.0; 282 and 346nm ( 27.600 and 7,200) in H2O pH 7.0; 256, 284 and 366nm ( 24600, 24,500 and 86,00) in H2O pH 13 [Rabinowitz in The Enzymes (Boyer et al. Eds), 2 185 1960]. [Beilstein 26 III/IV 3944.]