Ascorbic Acid:
Ascorbic Acid is a white crystalline compound of relatively simple structure. It is closely related to the monosaccharide sugars. It is synthesized from glucose and other simple sugars by plans and by most animal species. It can be prepared synthetically at a low cost from glucose. Ascorbic acid estimated by chemical methods in milligrams.
Characteristics of Ascorbic Acid:
1. Of all vitamins, ascorbic acid is the most easily destroyed.
2. It is highly soluble in water.
3. It gets oxidized by heat, light alkalies, oxidative enzymes and traces of copper and iron.
4. Oxidation is reduced markedly in an acid reaction and when the temperature is reduced.
Functions of Ascorbic Acid:
1. One of the main functions of ascorbic acid is the formation of collagen, a protein that forms the intracellular substance in cartilage, bone matrices, dentine and the vascular epithelium. In the synthesis of collagen, ascorbic acid is necessary for the Hydroxylation of proline and lysine to hydroxyproline and hydroxylysine.
These hydroxyamino acids are important constituents of collagen. This function also helps explain the importance of vitamin C in wound healing and the ability to withstand the stress of injury and infection.
2. Ascorbic Acid also plays an important role in other hydroxylation reactions like conversion of tryptophan to serotonin which is an important neurotransmitter and vasoconstrictor. It formation of norepinephrine from tyrosine and conversion of cholesterol to bile acids.
3. Ascorbic acid is an important antioxidant and plays a role in protecting vitamin A and E and also polyunsaturated fetty acids from getting excessive oxidation.
4. It enhances iron absorption by reducing ferric iron to ferrous iron the form in which iron is efficiently absorbed.
5. In the circulation, ascorbic acid helps in the release of iron from transferrin so that it can be incorporated into tissue ferritin.