title: A critical evaluation of the present status of toxicity of aminoxyl radicals.
abstract: The literature on the toxicity of aminoxyl radicals was critically reviewed. It was concluded that, in general, the aminoxyl radicals possess a very low toxicity and are not mutagenic. In support of this contention, several aminoxyl radicals were evaluated in vitro. Thus, aminoxyl radicals 3-carboxy-2,2,5,5-tetramethylpyrroline-1-oxyl (1), 3-carboxy-2,2,5,5-tetramethylpyrrolidine-1-oxyl (PCA; 2), 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempol;3), and N-(1-hydroxymethyl-2,3-dihydroxypropyl)-3-carboxyamino-2,2,5,5- tetramethylpyrrolidine-1-oxyl (NAT; 4) were evaluated using Salmonella typhimurium tester strains TA 102 and TA 104, with a supplement of xanthine oxidase enzyme. 1, 2, and 4 were found to be nonmutagenic, while 3 elicited in TA 104 only about a twofold increase in the number of revertants above the control. This response is considered to be, at best, marginal in view of wide fluctuations of experimental scores. The results of the present study are in agreement with those of other studies confirming the nonmutagenicity of aminoxyl radicals investigated to date. However, these conclusions are different from those of a study where 3 was tested in the presence of a generated toxic oxygen species that can cause mutagenic changes of the environment.
authors.affiliation: Department of Chemistry, University of Wisconsin-Milwaukee 53201.
authors.forename: G
authors.initials: G
authors.lastname: Sosnovsky
mesh_terms: D000818:Animals; D003497:Cyclic N-Oxides / Q000737:chemistry / Q000633:toxicity*; D005609:Free Radicals; D066298:In Vitro Techniques; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*; D051381:Rats; D012486:Salmonella typhimurium / Q000235:genetics; D014969:Xanthine Oxidase / Q000235:genetics / Q000378:metabolism
chemical_list: D003497:Cyclic N-Oxides; D005609:Free Radicals; D009153:Mutagens; D014969:Xanthine Oxidase