Vitamins oxidation

Furthermore, mice treated with anti-oxidants (Vitamins C, or E, or beta-hydroxy toluene) prior to JP-8 dermal application exhibit a partial recovery in immune function... 

Nitrous oxide exerts a variety of its adverse effects by oxidizing vitamin Bn and rendering it inactive as a coenzyme in many essential metabolic processes. One vitamin dependent enzyme in particular, methionine synthetase, is involved in cell division and is necessary for DNA production. Adverse reproductive and hematologic effects caused by nitrous oxide are thought to be due to inactivation or dysfunction of methionine synthetase resulting in impairment of cell division. 

To some extent the vitamin E requirement may be lessened by the presence in the diet of synthetic antioxidants and by selenium. Much evidence supports a relationship between the nutritional need for selenium and that for vitamin E. Lack of either causes muscular dystrophy in many animals as well as severe edema (exudative diathesis) in chicks. Since vitamin E-deficient rats have a low selenide (Se2 ) content, it has been suggested that vitamin E protects reduced selenium from oxidation.) Vitamin C (ascorbic acid), in turn, protects vitamin E. 

In the 40 s, during studies on the preparation of retinene, Ball et al. needed to oxidized vitamin A (76) to the corresponding aldehyde 77. 

Ascorbic acid as a water-soluble vitamin (vitamin C) is an essential component in the human diet. As one of many anti-oxidants (vitamin E and 3-carotene are examples of fat-soluble anti-oxidants), ascorbic acid is required for the growth and repair of tissues in all parts of the body. It is necessary to form collagen, an important protein used to make skin, scar tissue, tendons, ligaments, and blood vessels. 

To prevent this sun-induced cascade of oxidative injuries, topical preparations containing antioxidants have been developed in the past several decades. Initially, such antioxidants were added as stabilizers to various dermatologic and cosmetic preparations. In particular, lipophilic Vitamin E has been the favorite as a stabilizing agent. However, following oxidation, Vitamin E is degraded into particularly harmful prooxidative metabolites.177... 

Moreover, when 02 is formed in the hydrophobic stage, vitamin E (20, tocopherol) creates a hydrogen atom. The hydrogen peroxide formed is decomposed to water and molecular oxygen catalyzed by catalase enzyme (protein containing Fe-complex), and the oxidized vitamin E radical is reduced to vitamin E again by vitamin C (eq. 1.10)... 

The oxidative product of ascorbic acid, dehydroascorbic acid, is the preferred form of the vitamin for uptake by neutrophils, erythrocytes, and lymphocytes (27). Once within the erythrocyte, dehydroascorbic acid is reduced to ascorbic acid by a glutathione-dependent, dehydro-ascorbic-acid-reducing enzyme (20,28). However, the reduced form of ascorbic acid is found in most other tissues, that is, liver, lungs, kidneys, skin, and pituitary and adrenal glands (20,29). From these studies, ascorbic acid is taken up by several tissues by an energy-dependent and Na -sensitive process, but the transport of the oxidized vitamin form follows the principles of diflFusion. 

Food additives can enhance the safety and nutritional quality of a food or vice versa. By preventing oxidation of fat and easily oxidized vitamins, antioxidants ensure that safety is enhanced and the intended nutritional value of the food is delivered. Antibrowning agents such as sulfite retain phytochemicals and vitamins A and C but lower the amount of thiamine, folate, and pyridoxal. Sorbic acid can prevent... 

It has been reported (Leiner and Leiner, 1944) and confirmed (Bowness et al., 1952) that retina contains high concentrations of zinc. Horse liver ADH oxidizes vitamin Ai and reduces retinene, probably being identical with retinene reductase (Bliss, 1949 Theorell and Bonnichsen, 1951a). 

As can be seen from the equations above, the necessary amount of malonyl CoA is synthesized. Palmitate is subsequently synthesized from malonyl CoA and one initial acetyl CoA. Thus, acetyl CoA, NADPH, ATP, and HCOs are all necessary in this process. In contrast, FADH, is not utilized in fatty acid synthesis, but is one of the products of fatty acid oxidation. Vitamin is required for conversion of propionic acid to methylmalonic acid, a step in the p oxidation of odd-numbered fatty acid chains. 

Antioxidants Compounds that are easily oxidized can act as antioxidants to prevent other compounds from being oxidized. Vitamins C and E protect living cells from oxidative damage by acting as antioxidants. Why does adding lemon juice to fruit salad prevent browning of the fruit ... 

Mammalian dihydrofolate reductases can also catalyze the transfer of a hydride ion to the C-7 position of folate in a reaction affording dihydrofolate, thus enabling the utilization of the fully oxidized vitamin from nutritional sources/ ... 

Stocker, A. and Baumann, U., Supernatant protein factor in complex with RRR-alpha-tocopherylquinone a link between oxidized Vitamin E and cholesterol biosynthesis, J. Mol. Biol. 332 (4), 759-765, 2003. 

Control of Lipid Oxidation Vitamins as Natural Antioxidants.391... 

CONTROL OF LIPID OXIDATION VITAMINS AS NATURAL ANTIOXIDANTS... 

Cyanopsin. Fish pigment of vision from 3-dehydro-retinal (oxidized vitamin A2) and opsin of the retinal uvula. The replacement of retinal by 3-dehydroretinal leads to a red-shifted absorption of visual pigment and is considered as an adaptation to the changed spectral distribution of incident light underwater. 

Protection from oxidation (vitamin A. retinol, hydro-quinone, arbutin, DHA, etc.). 

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