| Abstract
| - The mechanism of interaction of the peroxynitrite with some 4-alkylphenols and tyrosine was mainlystudied by means of ESR spectroscopy and product analysis. The radical intermediates, detectedas spin adducts to the 5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide (DEPMPO), wereidentified as carbon-centered radicals to the benzene ring. The reaction seems to proceed via anelectron transfer process (ET), most likely mediated by a NOx derivative, leading to the intermediacyof a phenoxyl-type radical as proved by the detection of the corresponding Pummerer-type ketone.No evidence of the formation of hydroxyl radicals, due to the homolytic cleavage of the peroxynitriteat physiological pH was obtained, even though DEPMPO hydroxyl spin adducts were detected: the latter most likely arises from the direct attack of the spin trap by the oxidant species. Thepossible involvement of HCO3-/CO2, i.e., the formation of the nitrosoperoxycarbonate, ONOOCO2•-,was also investigated.
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