Antioxidative state

Kristenson, M. et al., Antioxidant state and mortality from coronary heart disease in Lithuanian and Swedish men concomitant cross-sectional study of men aged 50, Br. Med. J., 314, 629, 1997. 

The antioxidative state of the organism can be defined by the antioxidizability and the oxidation state of blood components. The investigation includes mea-... 

Taking into account the important role of balance in oxidant-antioxidant phenomena for human health and interrelation between internal and external factors, evaluation of oxidant-antioxidant state of human body fluids and natural resources of antioxidants is essential for therapy and prevention of diseases and adverse effects of environment. Thus, analysis of ready-made food and production processes monitoring are of great importance. 

Kristenson, M., Zieden, B., Kucinskiene, Z., Abaravicius, A., Razinkoviene, L., Elinder, L.S., Berg-dahl, B., Elwing, B., Calkauskas, H., and Olsson, A.G. 1997. Antioxidant state and mortality from coronary heart disease in Lithuanian and Swedish men Concomitant cross sectional study of men aged 50. BMJ 314, 629-633. 

Malondialdehyde is an end product of lipid peroxidation. For assessing the oxidative/antioxidative state of biological samples, simultaneous determination of malondialdehyde and ascorbic acid has been described (88). The detection was at 266 nm in mobile-phase pH 5.5. The method was adapted for ischemic and reperfused rat heart and human erythrocytes after in vitro peroxidation. However, it was obvious that the method was not sensitive enough for malondialdehyde measurements without strong in vitro induction of malondialdehyde generation. 

Heico Chemicals is the only producer of acetamide in the United States. Small amounts are imported from Europe and Asia. It is shipped in 32-L (35-gal) dmms weighing about 80 kg. Acetamide appears to have a wide spectmm of appHcations. It suppresses acid buildup in printing inks, lacquers, explosives, and perfumes. It is a mild moisturi2er and is used as a softener for leather, textiles, paper, and certain plastics. It finds some appHcations in the synthesis of pharmaceuticals, pesticides, and antioxidants for plastics. 

The basic metal salts and soaps tend to be less cosdy than the alkyl tin stabilizers for example, in the United States, the market price in 1993 for calcium stearate was about 1.30— 1.60, zinc stearate was 1.70— 2.00, and barium stearate was 2.40— 2.80/kg. Not all of the coadditives are necessary in every PVC compound. Typically, commercial mixed metal stabilizers contain most of the necessary coadditives and usually an epoxy compound and a phosphite are the only additional products that may be added by the processor. The requited costabilizers, however, significantly add to the stabilization costs. Typical phosphites, used in most flexible PVC formulations, are sold for 4.00— 7.50/kg. Typical antioxidants are bisphenol A, selling at 2.00/kg Nnonylphenol at 1.25/kg and BHT at 3.50/kg, respectively. Pricing for ESO is about 2.00— 2.50/kg. Polyols, such as pentaerythritol, used with the barium—cadmium systems, sells at 2.00, whereas the derivative dipentaerythritol costs over three times as much. The P-diketones and specialized dihydropyridines, which are powerful costabilizers for calcium—zinc and barium—zinc systems, are very cosdy. These additives are 10.00 and 20.00/kg, respectively, contributing significantly to the overall stabilizer costs. Hydrotalcites are sold for about 5.00— 7.00/kg. 

Nut Products. Peanut products iaclude peanut flour, Hpoproteia, proteia, milk, and partially defatted peanuts (109). Pecan butter is made from dry roasted meats, ground to a very fine state, and mixed with salt (2% of final weight), hydrogenated fat (1.5%), and the antioxidant butylated hydroxyanisole (BHA) (131). 

The chemical industry manufactures a large number of antioxidants (qv) as well as uv stabilizers and their mixtures with other additives used to facilitate resin processing. These companies include American Cyanamid, BASE, Ciba—Geigy, Eastman Chemical, Elf Atochem, Enichem, General Electric, Hoechst—Celanese, Sandoz, and Uniroyal, among others. The combined market for these products in the United States exceeded 900 million in 1994 and will reach 1 billion in the year 2000. 

The use of vitamins in humans consumes ca 40% of vitamins made worldwide. The majority of the vitamins, particularly in countries outside the United States, are used in animal husbandry. It is well estabUshed (21) that vitamins are critical to animal productivity, especially under confined, rapid growth conditions. Newer information (22) has shown that vitamin E added to catde feed has the additional effect of significantly prolonging beef shelf life in stores. Additional appHcations of vitamins exist. A small but growing market segment involves cosmetics (qv) (23). The use of the chemical properties of the vitamins, particularly as antioxidants (qv) in foods and, more recently, in plastics (vitamin E (24)), has emerged as a growing trend. 

Antioxidants are used to retard the reaction of organic materials with atmospheric oxygen. Such reaction can cause degradation of the mechanical, aesthetic, and electrical properties of polymers loss of flavor and development of rancidity ia foods and an iacrease ia the viscosity, acidity, and formation of iasolubles ia lubricants. The need for antioxidants depends upon the chemical composition of the substrate and the conditions of exposure. Relatively high concentrations of antioxidants are used to stabilize polymers such as natural mbber and polyunsaturated oils. Saturated polymers have greater oxidative stabiUty and require relatively low concentrations of stabilizers. Specialized antioxidants which have been commercialized meet the needs of the iadustry by extending the useflil Hves of the many substrates produced under anticipated conditions of exposure. The sales of antioxidants ia the United States were approximately 730 million ia 1990 (1,2). 

Commercial Antioxidants Table 4 includes the main classes of antioxidants sold in the United States and the suppHer s suggested apphcations. Some of these are mixtures rather than single substrates. This is especially tme of alkylated amines and alkylated phenols. The extent of alkylation and the olefins used for alkylation can vary among manufacturers. Table 4 is not a complete listing of available antioxidants in the United States. 

Monochlorobenzene. The largest use of monochlorobenzene in the United States is in the production of nitrochlorobenzenes, both ortho and para, which are separated and used as intermediates for mbber chemicals, antioxidants (qv), dye and pigment intermediates, agriculture products, and pharmaceuticals (Table 5). Since the mid-1980s, there have been substantial exports of both o-nitrochlorobenzene, estimated at 7.7 million kg to Europe and -nitrochlorobenzene, estimated at 9.5 million kg to the Far East. Solvent use of monochlorobenzene accounted for about 28% of the U.S. consumption. This appHcation involves solvents for herbicide production and the solvent for diphenylmethane diisocyanate manufacture and other chemical intermediates. 

The proximity of the methyl group to the double bond in natural rubber results in the polymer being more reactive at both the double bond and at the a-methylenic position than polybutadiene, SBR and, particularly, polychlor-oprene. Consequently natural rubber is more subject to oxidation, and as in this case (c.f. polybutadiene and SBR) this leads to chain scission the rubber becomes softer and weaker. As already stated the oxidation reaction is considerably affected by the type of vulcanisation as well as by the use of antioxidants. 

Consequently, the antioxidant activity of GA in biological systems is still an unresolved issue, and therefore it requires a more direct knowledge of the antioxidant capacity of GA that can be obtained by in vitro experiments against different types of oxidant species. The total antioxidant activity of a compound or substance is associated with several processes that include the scavenging of free radical species (eg. HO, ROO ), ability to quench reactive excited states (triplet excited states and/ or oxygen singlet molecular 1O2), and/or sequester of metal ions (Fe2+, Cu2+) to avoid the formation of HO by Fenton type reactions. In the following sections, we will discuss the in vitro antioxidant capacity of GA for some of these processes. 

Besides all the sensory and texturizing properties, GA has interesting antioxidant properties such as an efficient capacity for deactivation of excited electronic states and moderated radical scavenging capacity. There is increasing experimental evidence that associate the antioxidant function with its protein fraction, mainly by amino acid residues such as histidine, tyrosine and lysine, which are generally considered as antioxidants molecules (Marcuse, 1960,1962 Park et al., 2005). 

The scavenging mechanism states that antiozonants function by migrating towards the surface of the rubber and, due to their exceptional reactivity towards ozone, scavenge the ozone before it can react with the rubber [60]. The scavenging mechanism is based on the fact that all antiozonants react much more rapidly with ozone than do the double bonds of the rubber molecules. This fact distinguishes antiozonants from antioxidants. 

Epinephrine is an inherently unstable chemical in aqueous solution, even at a low pH and in the presence of an antioxidant such as sodium metabisulfite, up to 1 mg/ ml. With the passage of time, the epinephrine dose gradually decreases due to degradation into inactive compounds. If the expiry date has passed, the epinephrine dose correlates inversely with the number of months or years past that date, and will likely be lower than the dose stated on the label even if the solution appears clear and colorless. Nevertheless, if this is the only source of epinephrine available for injection, it should be used in preference to not administering epinephrine at all [32]. 

Figure 45-6. Interaction and synergism between antioxidant systems operating in the lipid phase (membranes) of the cell and the aqueous phase (cytosol). (R-,free radical PUFA-00-, peroxyl free radical of polyunsaturated fatty acid in membrane phospholipid PUFA-OOH, hydroperoxy polyunsaturated fatty acid in membrane phospholipid released as hydroperoxy free fatty acid into cytosol by the action of phospholipase Aj PUFA-OH, hydroxy polyunsaturated fatty acid TocOH, vitamin E (a-tocopherol) TocO, free radical of a-tocopherol Se, selenium GSH, reduced glutathione GS-SG, oxidized glutathione, which is returned to the reduced state after reaction with NADPH catalyzed by glutathione reductase PUFA-H, polyunsaturated fatty acid.)...

Besides other functions, vitamin Bj2 and fohc acid take part in providing one-carbon residues for DNA synthesis, deficiency resulting in megaloblastic anemia. Vitamin C is a water-soluble antioxidant that maintains vitamin E and many metal cofactors in the reduced state. 

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