Hydroxyl radical, scavenging effect

Moorhouse, C.P., Halliwell, B., Grootveld, M. and Gutteridge, J.M.C. (1985). Cobalt(ll) ion as a catalyst of hydroxyl radical and possible crypto-hydroxy radical formation under physiological conditions. Differential effects of hydroxyl radical scavengers. Biochem. Biophys. Acta 843, 261-268. 

Idebenone, an inhibitor of lipid peroxidation, was shown to prolong survival time and delay the onset of ischaemic seizures in a bilateral carotid occlusion model in rats. It is marketed in Japan as a therapy to improve cerebral metabolism and performance after a stroke (Suno and Nagaoka, 1984). Cerebral protective effects after an ischaemic insult in dogs and rabbits have been seen with the hydroxyl radical scavenger, mannitol (Meyer et al., 1987). 

The rate law of Eq. (15) holds at all pHs, despite the fact that is strongly pH dependent (see below). Free radical oxidation chemistry (60) appears not to be involved in these Fem-TAML catalyzed oxidations to any detectable degree. The efficient hydroxyl radical scavenger, mannitol (61,62), when added over the concentration range (0.5-2.0) x 10 3 M has no effect on the rate. This peroxide oxidation catalyzed by 1 does not proceed extensively via the hydroxyl free radical serving as the reactive intermediate. 

Burkitt MJ, Duncan J (2000) Effects of frans-resveratrol on copper-dependent hydroxyl-radical formation and DNA damage evidence for hydroxyl-radical scavenging and a novel, glutathionesparing mechanism of action. Arch Biochem Biophys 381 253-263 Buxton GV (1987) Radiation chemistry of the liquid state. (1) Water and homogeneous aqueous solutions. In Farhataziz, Rodgers MAJ (eds) Radiation chemistry principles and applications. Verlag Chemie, Weinheim, pp 321-349... 

Cullis PM, Langmann S, Podmore ID, Symons MCR (1990) Effects of ionizing radiation on deoxyribonucleic add. Part VI. - Effects of hydroxyl radical scavengers on radiation damage to DNA. J Chem Soc Faraday Trans 86 3267-3271... 

Radiolysis of HN03 generates different radicals (305), but at high acidity, HN03 can also act as a hydroxyl radical scavenger (306). Moreover, postirradiation effects have been observed (variation of the concentration of radicals, for example) (305). 

Liu and Ng (2000) studied the antioxidative and superoxide- and hydroxyl-radical-scavenging activities and pro-oxidant effect of 12 selected medicinal herbs. The aqueous extracts of Coplis... 

EGb 761 might also directly scavenge peroxynitrites and inhibit lipid peroxidation because it has been reported both to block the cytotoxicity induced by peroxynitrites and inhibit cyclosporine-A-induced peroxidation. This hypothesis is supported by the finding that the purported anti-ischemic agent ebselen completely protected and rescued hippocampal cells against SNP-induced toxicity. In contrast, the hydroxyl radical scavenging properties of EGb 761 do not seem able to account for its protective effects because catalase failed to display any neuroprotective properties in this model. 

Most of the examined compounds, including melatonin, have no significant inhibitory effect on superoxide anion formation but do have significant effects on LP. This shows that melatonin and the melatonin analogue indole derivatives act more like potent hydroxyl radical scavengers in vitro. 

The effects of hydroxyl radical scavenging by methanol were predicted accurately. For more complex compounds and for high concentrations, a detailed knowledge of the reaction mechanism is necessary to obtain good agreement between empirical and modeled results. 

More recently, the notion that the beneficial effects of iron-chelating agents are simply due to chelation of the metal ion has been challenged [64]. This is due to the demonstrated ability of the commonly used hydroxamate iron chelator desferrioxamine to act as a superoxide and hydroxyl-radical scavenger [65]. The relatively stable desferrioxamine nitroxide free radical (T1/2 10 min)... 

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