ascorbic acid

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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]
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 ?
Vitamin C in its active form as L-ascorbic acid has multiple skin benefits, but its susceptibility to oxidation limits stability in topical preparations.
5 mg/ml, mycelia (grinded) 75 mg/ml and L-ascorbic acid 5 mg/ml were dispensed in acetate buffer (pHo 3.
However, for the body to use the supplied ascorbic acid, it must convert it to L-ascorbic acid and many of the stabilized, commercially available forms have not been examined to determine whether this conversion is possible.
The broth had been supplemented with either L-ascorbic acid or propyl gallate alone or in combination with lactic acid.
00 ml) were pipetted into volumetric flasks (100 ml), pH value was adjusted to 2 with water and hydrochloric acid, thereafter L-ascorbic acid solution (2.
Although conflicting results have been reported in human studies about the effect of L-ascorbic acid and [alpha]-tocopherol supplementation on oxidative stress, the experimental animal results with ascorbic acid suggest that a high consumption of dietary L-ascorbic acid and [alpha]-tocopherol might ameliorate oxidative stress induced by nickel.
Schwarzhoff and Cody studied the effect of 16 different adulterating agents: ammonia-based cleaner, L-ascorbic acid, Visine eye drops, Drano, golden-seal root, lemon juice, lime solvent, Clorox, liquid hand soap, methanol, sodium chloride, tribasic potassium phosphate, toilet-bowl cleaner (Vanish, Drackett Products), white vinegar, ionic detergent (Multi-Terge), and whole-blood anticoagulated with EDTA on the FPIA (flourescence polarization immunoassay) for testing abused drugs in urine.
They include the treatment of must and fermenting wine with charcoal, employing L-ascorbic acid, adding dimethyldicarbonate (DMDC) and using yeast mannoproteins.
Growth inhibition of neuroblastoma cells by lovastatin and L-ascorbic acid is based on different mechanisms.