Antioxidants free radicals

Antioxidant free radicals (A H) produced in this way are relatively stable, but they may react with another lipid free radical to form a quinone [15.3] and [15.4]. Quinones can react with amine or thiol groups of proteins, forming polymerisable yellow or red coloured compounds (Pokorny, 1987). Antioxidant free radicals may also react with either another antioxidant free radical or a lipid free radical, forming dimers [15.5] or copolymers [15.6] and [15.7], respectively. Oligomeric or condensated products of antioxidant free radicals usually possess moderate antioxidant activities too (Pokorny et al, 1974) ... 

Cao G, Alessio HM and Cutler RG. 1993. Oxygen-radical absorbance capacity assay for antioxidants. Free Radic Biol Med 14(3) 303-311. 

Plumb, GW, Lambert N, Chambers, SJ, Wanigatunga S, Heaney, RK, Plumb, JA, Aruoma, OI, Halliwell B, Miller, NJ and Williamson, G. 1996. Are whole extracts and purified glucosinolates from cruciferous vegetables antioxidants . Free Radic Res 25(l) 75-86. 

Popov IN and Lewin G. 1994. Photochemiluminescent detection of antiradical activity. II. Testing of nonenzymic water-soluble antioxidants. Free Radic Biol Med 17(3) 267—271. 

Synergistic Interaction of Antioxidants, Free Radical Scavengers, and Chelators... 

RE Pliss, VA Machtin, EM Pliss. In Abstracts of Conference Regulation of Biological Processes by Free Radicals Role of Antioxidants, Free Radical Scavengers, and Chelators. Moscow, Yaroslavl, Yaroslavl State Technical University, 1998, p 17. 

SYNERGISTIC INTERACTION OF ANTIOXIDANTS, FREE RADICAL SCAVENGERS, AND CHELATORS... 

Kodavanti, J. D. Crapo, L. Y. Chang, and K. E. Pinkerton. Inhibition of tobacco smoke-induced lung inflammation by a catalytic antioxidant. Free Radic Biol Med 2002 33(8) 1106-1114. 

An antioxidant ties up the peroxy radicals so that they are incapable of propagating the reaction chain or to decompose the hydroperoxides in such a manner that carbonyl groups and additional free radicals are not formed. The former, which are called chain-breaking antioxidants, free-radical scavengers, or inhibitors. are usually hindered phenols or amines. The latter, called peroxide decomposers, are generally sulfur compounds or... 

Fat Free Radical as well as the propagation step H Original Fat Molecule Antioxidant Free Radical... 

Oliveira, C. M., Ferreira, A. C. S., Guedes de Pinho, P., and Silva, A. M. S. (2008). New qualitative approach in the characterization of antioxidants in white wines by antioxidant free radical scavenging and NMR techniques. J. Agric. Food Chem. 56,10326-10331. 

Aviram, M. et al., Human serumparaoxonase (PON1) is inactivated by oxidized low density lipoprotein and preserved by antioxidants, Free Radic. Biol. Med., 26, 892,1999. 

Tanguy, S., Boucher, F.R., Malfroy, B., and de Leiris, J.G. 1996. Free radicals in reperfusion-induced arrhythmias study with EUK 8, a novel nonprotein catalytic antioxidant. Free. Radical Biol. Med. 21 945-954. 

Stobadine ((-)-cis-2,8 dimethyl-2,3,4,4a,5,9b-hexahydro-l-H-pyrido (4,3b) indole) is a model drug with pyridoindole structure with cardioprotective and antioxidant properties [109]. Based on stobadine, (-)-ris-2,8-dimethyl-2,3,4,4a,5,9b-hexahydro-lH-pyrido[4,3-b]indole (Fig. 4), a well-known antioxidant, free-radical scavenger and neuroprotectant, stobadine derivatives with improved pharmacodynamic and toxicity profiles were developed [110]. A stobadine molecule was modified mostly by electron donating substitution on the benzene ring and by alkoxycarbonyl substitution at N-2 position. Significant antioxidant activity was observed in the new compounds. A link... 

The antioxidant free radical deactivated by further oxidation to quinones, thus terminating the chain. Only phenolic compounds that can easily produce quinones are active as antioxidants (Pokomy 1971). At high concentrations antioxidants may have a prooxidant effect and one of the reactions may be as follows ... 

Simple stilbenes (Phe-CH=CH-Phe) include the Vitis vinifera (grape) (Vitaceae) cytotoxic resveratrol (4,3, 5 -trihydroxystilbene), the mitochondrial electron transport inhibitor oxyresveratrol (3,5,2, 4 -tetrahydroxystilbene) and the protein kinase inhibitor piceatannol (3,4,3, 5 -tetrahydroxystilbene), all these compounds having antifungal activity. The isoprenylated stilbene chlorophorin (4-geranyl-3,5,2, 4 -tetrahydroxystilbene) is an antioxidant free radical scavenger (AO/FRS). 

Halliwell B. (1990) How to characterize a biological antioxidant. Free Radic Res Commun 9 1-32. 

Bors, W., Saran, M. Radical scavenging by flavonoid antioxidants. Free Radic. Res. Conunun. 1987 2 289 - 294... 

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