- Country of manufactureChina
- Maximum permissible level4 g
L-ascorbic acid (ﻻ - a lactone of 2,3-degidro-L-gulonic acid; a formula I) - molecular weight 176,12; colourless crystals; t of melting of 190-192 °C (with decomposition). Specific optical rotation for the D-line of sodium at a temperature of 20 °C: [α] D20 + 23 ° (concentration of 1,6 g in 100 ml of water); it is well soluble in water (22,4%), it is worse - in alcohol (4,6%), it is bad - in glycerin and acetone; rka4,17 and 11,57; λmax245 (rn <7) and 265 nanometers (rn> 7).
Dehydroascorbic acid (ﻻ - a lactone of 2,3-diketo-L-gulonic acid; a formula - II) - molecular weight 174,12; colourless crystals; t of melting of 237-240 °C (with decomposition). Specific optical rotation for the D-line of sodium at a temperature of 20 °C: [α] D20+55 °; it is soluble in water.
Ascorbic acid is steady in a dry form in the dark. In aqueous solutions, especially in the alkaline environment, quickly is oxidized reversibly to a dehydroascorbic kislta (okisliyelno-recovery potential + 0,058 B) and further it is irreversible to 2,3-diketogulonic, and then to oxalic acid.
Ascorbic acid - a reducer. With solutions of alkalis forms enolyata, with acid chlorides of higher fatty acids - esters, with cations of metals (for example, Sa2+, Mg2+, Fe3+) - complexes. Under the influence of NSL turns into furfural. Ascorbic acid is synthesized by all hlorofillsoderzhashchy plants, reptiles and amphibiouses. Invertebrates, fishes, high-organized bird species and some mammals (for example, the person, monkeys, Guinea pigs, a number of bats) lost ability to its biosynthesis as a result of loss during evolution of ability of these organisms to synthesis of a number of enzymes.
Biosynthesis of ascorbic acid comes mainly from glucose or a galactose. Degidroaskorbinovy acid is formed of ascorbic. The catabolism of ascorbic acid at the person and animals proceeds with formation of the same products, as at its oxidation.
Vitamin C is necessary for creation of intercellular substance, regeneration and healing of fabrics, maintenance of integrity of walls of veins, providing the normal hematologic and immunological status of an organism and its resistance to an infection and a stress. Biochemical mechanisms of its action are diverse and up to the end are not opened. Vitamin C participates: in functioning of the enzymes catalyzing a hydroxylation of a lysine and proline which plays an important role in formation of collagen; in a dopamine hydroxylation with education at the same time noradrenaline; in a cholesterol metabolism; in a metabolism of catecholamines and steroid hormones; in protection from oxidation of glutathione and SH groups of proteins; in recovery of Fe3+ in Fe2+ providing absorption of Fe in intestines; in regulation of free radical oxidation of fatty acids, etc.