ascorbic acid


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Related to ascorbic acid: citric acid

ascorbic acid:

see vitaminvitamin,
group of organic substances that are required in the diet of humans and animals for normal growth, maintenance of life, and normal reproduction. Vitamins act as catalysts; very often either the vitamins themselves are coenzymes, or they form integral parts of coenzymes.
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Ascorbic acid

A white, crystalline compound, also known as vitamin C. It is highly soluble in water, which is a stronger reducing agent than the hexose sugars, which it resembles chemically. Vitamin C deficiency in humans has been known for centuries as scurvy. The compound has the structural formula shown below.

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The stability of ascorbic acid decreases with increases in temperature and pH. This destruction by oxidation is a serious problem in that a considerable quantity of the vitamin C content of foods is lost during processing, storage, and preparation.

While vitamin C is widespread in plant materials, it is found sparingly in animal tissues. Of all the animals studied, only a few, including humans, require a dietary source of vitamin C. The other species are capable of synthesizing the vitamin in such tissues as liver and kidneys. Some drugs, particularly the terpene-like cyclic ketones, stimulate the production of ascorbic acid by rat tissues.

Vitamin C–deficient animals suffer from defects in their mesenchymal tissues. Their ability to manufacture collagen, dentine, and osteoid, the intercellular cement substances, is impaired. This may be related to a role of ascorbic acid in the forma- tion of hydroxy-proline, an amino acid found in structural proteins, particularly collagen. People with scurvy lose weight and are easily fatigued. Their bones are fragile, and their joints sore and swollen. Their gums are swollen and bloody, and in advanced stages their teeth fall out. They also develop internal and subcutaneous hemorrhages.

There is evidence that vitamin C may play roles in stress reactions, in infectious disease, or in wound healing. Therefore, many nutritionists believe that the human intake of ascorbic acid should be many times more than that intake level which produces deficiency symptoms. The recommended dietary allowances of the Food and Nutrition Board of the National Research Council are 30 mg per day for 1- to 3-month infants, 80 mg per day for growing boys and girls, and 100 mg per day for pregnant and lactating women. These values represent an intake which tends to maintain tissue and plasma concentrations in a range similar to that of other well-nourished species of animals. See Vitamin

ascorbic acid

[ə′skȯr·bik ′as·əd]
(biochemistry)
C6H8O6 A white, crystalline, water-soluble vitamin found in many plant materials, especially citrus fruit. Also known as vitamin C.

ascorbic acid

a white crystalline vitamin present in plants, esp citrus fruits, tomatoes, and green vegetables. A deficiency in the diet of man leads to scurvy. Formula: C6H8O6
References in periodicals archive ?
Ascorbic acid has antioxidant properties and affects melanogenesis by reducing dopaquinone to DOPA and preventing free-radical production and absorption of ultraviolet radiation.
01) was observed when the mean number of movements of Drosophila melanogaster treated with ascorbic acid (10.
Among these antioxidant supplements, ascorbic acid appears to be more effective in minimizing the toxicity of lead6,7.
Ascorbic acid is generally regarded as a primary first-line protective agent that repairs or nullifies Free Radicals by donating a single electron, followed by a proton to yield a chemically dehydroascorbic acid (Carr et al.
In 1995, Riordan published data demonstrating that sustained plasma levels of ascorbic acid in humans are toxic to tumor cells.
0 percents higher ascorbic acid peroxidase activity as compared to bolder grains at 7th, 14th, 21st and 28th DAA and at maturity respectively.
However, ascorbic acid showed a moderate protective effect.
Experiment 3 compared a single dose of ascorbic acid by mouth (10 grams) that was equivalent with the amount given IV.
Effect of treatment with ascorbic acid at various concentrations on the in vitro development of SCNT embryos
Foliar application of ascorbic acid at 40 mg L-1 reduced the cell injury and improved yield and related components under all heat treatments.