Nitric oxide, radical inhibitor

Oxidative stress and free-radicals The production of free-radicals and other reactive species has been much implicated in cytotoxicity. This topic is discussed in more detail elsewhere see ANTIOXIDANTS PREE-RADICAL SCAVENGERS nitric oxide synthase inhibitors. The production of these species in oxidative stress is well established. Advances in therapy may well be in the direction of boosting and augmenting natural defence processes, for example, by superoxide dismutase (SOD), catalase, a-tocopherol, glutathione, ascorbic acid and perhaps melatonin. Surprisingly, some forms of the enzyme SOD can be administered in vivo and are protective. 

Their rates are decreased or the reactions are suppressed entirely by substances that scavenge free radicals, e.g., nitric oxide, molecular oxygen, or benzoquinone. These substances are called inhibitors.1... 

Although nitric oxide is frequently used as an inhibitor in free radical reactions, its role is not fully understood. Presumably alkyl radicals first combine with the nitric oxide to form the nitrosoalkane ... 

The 2-butanone oxime could be readily separated from the oximes arising by interaction of the nitric oxide with the initially formed radicals from the decomposition of the substrate. By this mixed-inhibitor technique, low concentrations of NO could be used, and the NO(4II)-photosensitization of the alkane could therefore be obviated. 

Nitric oxide inhibits the formation of hydrocarbons in the photolysis of acetaldehyde. The results of the investigations -carried out in the presence of iodine as an inhibitor, furnish further convincing evidence in favour of the participation of free radicals. 

The peroxyacyl radical adds nitric oxide to produce R—C—0—O—NO. This is consistent with the fact that nitric oxide is itself a free radical with an unpaired electron and is commonly used as an inhibitor of free radical reactions. 

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