Nucleic acid radicals reactivity

Aside from oxidized nucleic acids, radical-mediated damage to cellular biomembranes results in lipid peroxidation, a process that genraates a variety of products including reactive electrophiles such as epoxides and aldehydes (JauCTo... 

Several powerful oxidants are produced during the course of metabolism, in both blood cells and most other cells of the body. These include superoxide (02 ), hydrogen peroxide (H2O2), peroxyl radicals (ROO ), and hydroxyl radicals (OH ). The last is a particularly reactive molecule and can react with proteins, nucleic acids, lipids, and other molecules to alter their structure and produce tissue damage. The reactions listed in Table 52-4 play an important role in forming these oxidants and in disposing of them each of these reactions will now be considered in turn. 

N-AryInitrones (XIII) formed by oxidation of N-hydroxy-N-methyl arylamines, show high reactivity toward carbon-carbon and carbon-nitrogen double bonds in non-aqueous media (21,203) (Figure 10). Under physiological conditions, however, it appears that N-arylnitrones exist as protonated salts that readily hydrolyze to formaldehyde and a primary N-hydroxy arylamine and efforts to detect N-arylnitrone addition products in cellular lipid, protein or nucleic acids have not been successful (204). Nitroxide radicals derived from N-hydroxy-MAB have also been suggested as reactive intermediates (150), but their direct covalent reaction with nucleic acids has been excluded (21). 

In these reactions that mediate the nucleic acid cleavage reactions by generation of reactive oxygen species (ROS), unwanted side effects such as lipid peroxidation and free radical induced toxicity may limit their use as has been postulated in case of Fe +/ +-gentamicin complexes. ... 

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