Inhibition antioxidants

Table 5. Free-Radical-Inhibiting Antioxidants or Reductants Useful in Cosmetics ...

Genistein (116) Isoflavone Genistein (116) Oncology (antitumor) Protein-tyrosine kinase inhibition, antioxidative Phase I/II Astellas, Bausch Lomb 708... 

Cyanide reversibly binds the ferric iron associated with the cytochrome oxidase system, thereby inhibiting the mitochondrial respiratory chain. This results in an inability to adequately utilize oxygen and causes internal asphyxia . Cyanide combines with hemoglobin to form cyanhemoglobin, which does not transport oxygen. Cyanide also inhibits antioxidant enzymes such as catalase, superoxide di-smutase, and glutathione peroxidase. 

Key Words Allium sativum, antilipemic platelet inhibition antioxidants cancer prevention P450 enzyme induction. 

Garlic has been shown to have significant effects on the cardiovascular system. Such areas include improvement in lipids, modest effects on blood pressure, platelet inhibition, antioxidant effects, and a decrease in fibrinolytic activity. In vitro studies have shown garlic possesses specific antiatherosclerotic effects such as reducing inducible nitric oxide synthase (iNOS) mRNA expression (10), inhibition of oxidized low-density lipoprotein (LDL)-induced lactate dehydrogenase (LDH) release and inhibition of oxidized LDL-induced depletion of glutathione (11). 

The proanthocyanidins are widely distributed in nature and often represent the active compounds of medicinal plants or plants showing human health beneficial effects. Reports of several in vitro assays demonstrate potentially significant antiviral, antibacterial, molluscicidal, enzyme-inhibiting, antioxidant, and radical-scavenging properties. " Their potential to interact with biological systems rests, at least in part, on the ability to form complexes with other biomolecules, thus emphasizing the necessity to accurately define... 

Fale, P. L., Amaral, F., Amorim Madeira, P.J., Sousa Silva, M., Florencio, M.H., Frazao, F.N., Serralheiro, M.L.M. (2012). Acetylcholinesterase inhibition, antioxidant activity and toxicity of Peumus boldus water extracts on HeLa and Caco-2 cell line s. Food Chem. Toxicol, 50(8), 2656-2662. 

Thioredoxin, a thiol-disulfide oxidoreductase, is possibly involved in antioxidant protection in human coronary arteries (424). Exercise-induced plasma oxidative stress could be responsible for the prevention of atherosclerosis by stimulating arterial antioxidant response. In addition, vitamin E could be deleterious in exercisers by inhibiting antioxidant enzyme buildup in the arterial wall in LDL receptor -/- male mice fed an atherogenic diet (425). 

An infusion of the pods inhibited the in vitro proliferation of mouse hepatocellular tumor (Tl) cells and induced apoptosis in the cells. The crude polyphenol fraction of carob pods exhibits in vitro lipid peroxidation-inhibiting, antioxidant, and free radical scavenging activities. ... 

There are, indeed, many biological implications that have been triggered by the advent of fullerenes. They range from potential inhibition of HIV-1 protease, synthesis of dmgs for photodynamic therapy and free radical scavenging (antioxidants), to participation in photo-induced DNA scission processes [156, 157, 158, 159, 160, 161, 162 and 163]. These examples unequivocally demonstrate the particular importance of water-soluble fullerenes and are summarized in a few excellent reviews [141, 1751. 

Derivatives of ubiquiaones are antioxidants for foodstuffs and vitamins (qv) (217,218). Ubichromenol phosphates show antiinflammatory activity (219). Chroman o1 compounds inhibit oxidation of fats and can be used ia treatment of macrocytic anemias (220). Monosulfate salts of 2,3-dimethoxy-5-methyl-6-substitutedhydroquiaone have been reported to be inhibitors of Hpid oxidation ia rats (221). Polymers based on chloranilic and bromanilic acid have been prepared and contain oxygenated quiaones (63), which are derived from 1,2,3,4-benzenetetrol (222). 

Rubber Chemicals. Sodium nitrite is an important raw material in the manufacture of mbber processing chemicals. Accelerators, retarders, antioxidants (qv), and antiozonants (qv) are the types of compounds made using sodium nitrite. Accelerators, eg, thiuram [137-26-8J, greatly increase the rate of vulcaniza tion and lead to marked improvement in mbber quaUty. Retarders, on the other hand (eg, /V-nitrosodiphenylamine [156-10-5]) delay the onset of vulcanization but do not inhibit the subsequent process rate. Antioxidants and antiozonants, sometimes referred to as antidegradants, serve to slow the rate of oxidation by acting as chain stoppers, transfer agents, and peroxide decomposers. A commonly used antioxidant is A/,AT-disubstituted Nphenylenediamine which can employ sodium nitrite in its manufacture (see Rubber chemicals). 

Sulfuiized and sulfurchlorinated unsaturated compounds and meicaptans are used as lubricant additives (antiwear, friction modification, load-carrying, extreme pressure and temperature, corrosion inhibition, and antioxidants), refinery catalyst regeneration compounds, steel processing (annealing) aids, and vulcanization catalysts (see Lubrication and lubricants). 

Tea extracts and tea polyphenols inhibit copper- and peroxide-induced oxidation of LDL in vitro (116,123,124). The inhibitory concentration for 50% reduction (IC q) values for inhibition of copper-induced oxidation of LDL by some phenoHc antioxidants are Hsted in Table 7. The IC q for epigaHocatechin gaHate was found to be 0.075 p.mM, which was the most potent of all the phenoHc antioxidants tested (123,124). Similar results have been reported elsewhere (115,116,125,126). 

A Vinyl-2-Pyrrolidinone. Commonly called vinylpyrrohdinone or VP, Al-vinyl-2-pyrrohdinone was developed in Germany at the beginning of World War 11. It is a clear, colorless Hquid that is miscible in all proportions with water and most organic solvents. It can polymerize slowly by itself but can be easily inhibited by small amounts of ammonia, sodium hydroxide (caustic pellets), or antioxidants such as N,lSf-di-j i -butyl- -phenylenediamine. It... 

Vitamin E can also act as an antioxidant (qv) in animals and humans alone or in combination with vitamin C (qv). Both are good free-radical scavengers with the vitamin C acting to preserve the levels of vitamin E (35). Vitamin E in turn can preserve the levels of vitamin A in animals (13). It has been shown that vitamin E reduces the incidence of cardiovascular disease (36—39). This most likely results from the antioxidant property of the vitamin which inhibits the oxidation of low density Hpoproteins (LDLs) (40—42). The formation of the oxidized LDLs is considered important in decreasing the incidence of cardiovascular disease (43). 

Radical Scavengers Hydrogen-donating antioxidants (AH), such as hindered phenols and secondary aromatic amines, inhibit oxidation by competing with the organic substrate (RH) for peroxy radicals. This shortens the kinetic chain length of the propagation reactions. 

The use of stabilisers (antioxidants) may, however, have adverse effects in that they inhibit cross-linking of the rubber. The influence of phenolic antioxidants on polystyrene-SBR alloys blended in an internal mixer at 180°C has been studied. It was found that alloys containing 1% of certain phenolic antioxidants were gel-deficient in the rubber phase.The gel-deficient blends were blotchy in appearance, and had lower flow rates compared with the normal materials, and mouldings were somewhat brittle. Substantial improvements in the impact properties were achieved when the antioxidant was added later in the mixing cycle after the rubber had reached a moderate degree of cross-linking. 

Following the action of extraordinary stimulants (hypoxic hypoxia, hypoxia + hyperoxia, hypodynamia + hyperthermia), animals demonstrate an accumulation of malonic dialdehyde with a simultaneous fall of antiradical activity of the liver tissue. A preliminary introduction to rats of acetylene amine 3,4,5-tris(morpho-linopropynyl)-l-methylpyrazole 103 and also of tocopherol antioxidant and gutumine antihypoxant averts activation of the lipid peroxidation processes. The inhibition of peroxidation with this agent is mediated by stabilization of ly-zosomal and mitochondrial membranes. Unsaturated amines prevent destruction of the organelle membranes provoked by UV irradiation and incubation at 37°C (pH4.7)(78MIl). 

It has been only found that some antioxidants and light stabilizers show the ability for partial inhibition of thermal destruction of the polyolefins. 

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