Antioxidant defence system

Meat products have to be stabilised in some cases, as meat lipids contain no natural antioxidants or only traces of tocopherols. Most muscle foods contain, however, an efficient multi-component antioxidant defence system based on enzymes, but the balance changes adversely on storage. The denaturation of muscle proteins is the main cause of the inbalance as iron may be released from its complexes, catalysing the lipid oxidation. Salting contributes to the negative effects of storage, as it enhances oxidation. Using encapsulated salt eliminates the deleterious effect of sodium chloride. 

Human chronic inflammatory diseases are characterized by populations of cells with altered regulation and function. A large body of evidence suggests that many of these cellular abnormalities may be linked to an increase in the production of free radicals and/or deficiencies of antioxidant defence systems. Oxygen free radicals attack cell structures, altering their function, and are cytotoxic. They have therefore been implicated in the pathogenesis of rheumatoid arthritis as well as many other human diseases (HaUiwell, 1991). 

The efficient removal of O2 and H2O2 vvill diminish OH formation and therefore antioxidant defence systems have evolved to limit their accumulation. Enzymic and low molecular weight antioxidants exist to scavenge free radicals as self-protection mechanisms. Some proteins exhibit antioxidant properties because they chelate transition-metal catalysts. The significance of antioxidants in relation to inflammatory joint disease is discussed below. 

Moysan, A., Marquis, I., Gaboriau, F., Santus, R., Dubertret, L. and Morliere, P. (1993). Ultraviolet A-induced lipid peroxidation and antioxidant defence systems in cultured skin fibroblasts. J. Invest. Dermatol. 100, 692-698. 

Kawase, T., Kato, S. and Lieber, C.S. (1989). Lipid peroxidation and antioxidant defence systems in rat liver after chronic ethanol feeding. Hepatology 10, 815-820. 

Galisteo M, Garcia-Saura MF, Jimenez R, Villar IC, Zarzuelo A, Vargas F, Duarte J. 2004. Effects of chronic quercetin treatment on antioxidant defence system and oxidative status of deoxycorticosterone acetate-salt-hypertensive rats. Mol Cell Biochem 259 91-99. 

In STZ-diabetic rat livers, the levels of mRNA of 1-gulonolactone oxidase, catalase, and glutathione peroxidase were decreased at 6 weeks, as well as that of plasma alpha 1 proteinase inhibitor 3.562 AA synthesis enzyme and recycling enzyme mRNAs were also decreased, as was the level of AA itself. It seems that the antioxidative defence system had been severely damaged. 

In partnership with ascorbic acid, GSH constitutes the body s major antioxidant defence system [31]. The liver is a main source of circulating GSH. It has been estimated that approximately 45 mmol (or 14 g) of GSH are released into the circulatory system of humans during a 24 h period [32]. 

Viarengo, A., Canesi, L., Martinez, P.G., Peters, L.D., Livingstone, D.R., 1995. Pro-oxidant processes and antioxidant defence systems in the tissues of the Antarctic scallop (Adamussium colbecki) compared with the Mediterranean scallop (Pecten jacobaeus). Comp. Biochem. Physiol. 11 IB, 119-126. 

Anandan R., Nair P. G., and Mathew S. 2004. Anti-ulcerogenic effect of chitin and chitosan on mucosal antioxidant defence system in HCl-ethanol-induced ulcer in rats. J Pharm Pharmacol 56 265-269. 

COH, but also facilitated electron transfer from cytochrome c to H2O2, finally generating ROS. Therefore, GO/PP in the C. elegans body had the ability to accelerate and enhance electron transfer between the interface of juglone/02, H2O2/COH, or cytochrome C/H2O2, which impaired the inherent antioxidant defence system and eventually resulted in dramatic toxicity to the worms. 

The testicular production of free radicals and the function of the antioxidative defence system have a role in infertility caused by defective sperm func-... 

In addition to its biosynthetic role, NADPH is the unique provider of reducing equivalents to maintain or regenerate the cellular detoxifying and antioxidant defence systems. NADPH is an important cofactor for P450 enzymes that... 

Manganese functions as the prosthetic group of a variety of enzymes, including superoxide dismutase, a part of the body s antioxidant defence system (section 7.4.3.1), pyruvate carboxylase in gluconeogenesis (section 5.7) and arginase in urea synthesis (section 9.3.1.4). Deficiency has been observed only in deliberate depletion studies. 

S. Falone., A. Mirabilio, M.C. Carbone, et al., Chronic exposure to 50Hz magnetic fields causes a significant weakening of antioxidant defence systems in aged rat brain, Int J Biochem Cell Biol 2008, vol. 12, pp. 2762-2770. 

Cellular systems have evolved a powerful and complex antioxidant defence system to limit inappropriate exposure to these stressors. a-Tocopherol is quantitatively the most important chain-breaking antioxidant in plasma and biological membranes. The antioxidant activities of chain-breaking antioxidants are determined primarily by how rapidly they scavenge peroxyl radicals, thereby preventing the propagation of free radical reactions. When the chromanol phenolic group of a-tocopherol (TOH) encounters a ROO it forms hydroperoxide (ROOH), and in the process a tocopheroxyl radical (TO ) is formed ... 

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