Пиридоксин

Химические свойства

crystalline solid

Физические свойства

It is one kind of B vitamins, containing pyridoxine or pyridoxal or pyridoxamine. Appearance: colorless crystals at room temperature. Solubility: soluble in water and ethanol. Stability: stable in acid liquor but easily destroyed in alkali liquor. Pyridoxol is resistant to high temperature, but pyridoxal and pyridoxamine are not.

История

The discovery of vitamin was tortuous and legendary. After fat-soluble A and water soluble B were discovered by the year of 1915, the discovery of vitamins entered into a rapid developed period. In separation process of riboflavin by Kuhn and his colleagues, they noticed the unusual relationship between growth-promoting activ ity and fluorescence of extracts. Then they supposed that the existence of no fluorescent substances were very necessary for growth-promoting activity of riboflavin. And they considered this phenomenon as the evidence of a second chem ical existence in the thermostable complex. At last, they named this substance as vitamin B6 .
Vitamin B6 is widely distributed in foods, including meats, whole-grain products (especially wheat), vegetables, and nuts. In the cereal grains, vitamin B6 is concen trated primarily in the germ and aleuronic layer. Thus, the refining of grains in the production of flours, which removes much of these fractions, results in substantial reductions of vitamin B6 content. The chemical forms of vitamin B6 tend to vary among foods between plant and animal origin: plant tissues contain most pyridox ine (the free alcohol form, pyridoxol), whereas animal tissues contain most pyri doxal and pyridoxamine.

Использование

pyridoxine HCL is a skin-conditioning agent that is also widely used in hair products.

Показания

Vitamin B6 deficiency

Определение

ChEBI: A hydroxymethylpyridine with hydroxymethyl groups at positions 4 and 5, a hydroxy group at position 3 and a methyl group at position 2. The 4-methanol form of vitamin B6, it is converted intoto pyridoxal phosphate which is a coenzyme f r synthesis of amino acids, neurotransmitters, sphingolipids and aminolevulinic acid.

Всемирная организация здравоохранения(ВОЗ)

Pyridoxine (vitamin B6) is listed in theWHO Model List of Essential Drugs.

Общее описание

The discovery of vitamin B₆ is generally ascribed to Paul Gy?rgy who first realized there was a vitamin that was distinctly different from vitamin B₂ in 1934. Pyridoxine (PN) is the C⁴ hydroxymethyl derivative, pyridoxal (PL) is the C⁴ formyl derivative and pyridoxamine (PM) is the C⁴ aminomethyl derivative of 5-(hydroxymethyl)- 2-methylpyridin-3-ol). Each of these are also converted to their corresponding 5'-phosphate derivatives referred to as pyridoxine 5'-phosphate (PNP), pyridoxal 5'-phosphate (PLP), and pyridoxamine 5'-phosphate (PMP), respectively . Because of their ability to interconvert, all are considered active forms of vitamin B₆ in vivo. Although PLP is the major coenzyme form, PMP can also function as a coenzyme primarily in aminotransferases. The major metabolite is 4-pyridoxic acid, which is excreted in the urine.

Фармаколо?гия

The metabolically active form of vitamin B6 is pyridoxal phosphate, which serves as a coenzyme of numerous enzymes, most of which are involved in the metabolism of amino acids. Vitamin B6 functions through the following general mechanisms: decarboxylation, transamination, racemization, elimination, replacement reactions, and β-group interconversions.
Pyridoxal phosphate is practically involved in all amino acid metabolism reac tions, such as transaminations, transsulfuration, and selenoamino acid metabolism, in both their biosynthesis and their catabolism. Vitamin B6 also plays an important role in the tryptophan–niacin conversion, histamine synthesis, neurotransmitter syn thesis, and hemoglobin synthesis.
Vitamin B6 has two roles in gluconeogenesis, transaminations and glycogen uti lization. It is required for the utilization of glycogen to release glucose by serving as a coenzyme of glycogen phosphorylase.

Клиническое использование

Pyridoxine is indicated in the treatment and prevention of known or suspected vitamin B₆ deficiency, which is most likely to occur in the setting of alcoholism in developed countries. At least seven genetic disorders that result in a vitamin B₆ deficiency syndrome in the presence of an adequate dietary intake have been identified. These result from defects in enzymes that are responsible for the bioactivation or utilization of vitamin B6.

Профиль безопасности

Moderately toxic by ingestion, subcutaneous, intravenous, and intraperitoneal routes. Human systemic effects: ataxia, local anesthetic, paresthesia. When heated to decomposition it emits toxic fumes of Nox