Peroxyl radical , antioxidant phenolic acids

Ellison DH, Salmon GA, Wilkinson F (1972) Nanosecond pulse radiolysis of methanolic and aqueous solutions of readily oxidizable solutes. Proc R Soc Lond A 328 23-36 Erben-Russ M, Bors W, Saran M (1987) Reactions of linoleic acid peroxyl radicals with phenolic antioxidants a pulse radiolysis study. Int J Radiat Biol 52 393-412 Eriksen TE, Fransson G (1988) Radical-induced oxidation of glutathione in alkaline aqueous solution. Radiat Phys Chem 32 163-167... 

Laranjinha, J.A., Almeida, L.M. Madeira, VM. (1994). Reactivity of dietary phenolic acids with peroxyl radicals antioxidant activity upon low density Upopiotein peroxidation. Biochemical... 

Polyphenols can act as antioxidants by a number of potential pathways. The most important is likely to be by free radical scavenging, in which the polyphenol can break the radical chain reaction. Polyphenols are effective antioxidants in a wide range of chemical oxidation systems, being capable of scavenging peroxyl radicals, alkyl peroxyl radicals, superoxide, hydroxyl radicals, nitric oxide and peroxynitrate in aqueous and organic environments [121]. This activity is due to the ability of donating an H atom from an aromatic hydroxyl group to a free radical, and the major ability of an aromatic structure to support an unpaired electron by delocalization around the 7i-electron system. Phenolic acids... 

Aliphatic alkoxyl radicals have reduction potentials of about 1600 mV vs SHE at pH 7 making them better oxidising agents than alkyl peroxyl radicals (E 1000 mV SHE) [130], Phenoxyl radicals usually have even lower reduction potentials, e.g. phenoxyl radical (CsHsO ) with E7 900 mV vj SHE and tocopheroxyl radical with E 500 mV vj SHE [130], and these can also be produced in vivo via the oxidation of phenols, such as the amino acid tyrosine, flavenoids and other phenolic antioxidants (e.g. tocopherols), or via the reduction of quinones. 

Com oil phenols have been studied with respect to their potential to scavenge the free radicals, the peroxyl radicals, the superoxide radicals, etc. The free radical scavenging activity of the phenolic acids using model free radicals such as l,7-diphenyl-2-picrylhydrazyl radical (DPPH ), or ABTS (2,2 -azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt cation radical) is often measured. TEAC (Trolox equivalent antioxidant capacity), FRAP (Ferric-reducing antioxidant capacity) and TRAP (total-radical-trapping antioxidant parameter) of the com oil are also used in order to obtain additional information, necessary to investigate the relation between the antioxidant intake and the oxidative stress related diseases (Stratil et al., 2008 Ceto et al., 2014 Apak et al., 2007). 

There is a growing interest in naturally occurring phenolic compounds that display biological antioxidant properties such as -hydroxycinnamic acid, ferulic zcid, caffeic acid/ and curcumin which are ubiquitous in plant food. It has been demonstrated that the interaction of the oxidizing OH adduct of DNA, poly-A and poly-G with hydrox-ycinnamic acid derivatives proceed via electron transfer. Cinnamic acid derivatives have been shown to be able to scavenge superoxide, peroxyl, and hydroxyl radicals. 

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