Metabolites of the biocide o-phenylphenol generate oxidative DNA lesions in V 79 cells

Incubation of the o-phenylphenol (OPP) metabolites, o-phenylhydroquinone (P HQ) and o-phenylbenzoquitlone (PBQ) with V 79 Chinese hamster cells led to a significant enhancement of the amount of 8-hydroxy-2'-deoxyguanosine (8-O H-dG) in nuclear DNA. With OPP no distinct induction of this lesion could b e observed. In addition, PHQ and PBQ were able to generate DNA single-stran d breaks (DNA SSB), while OPP failed to induce this lesion. All incubations were performed for 1 h without exogenous metabolic activations and the low est effective concentration tested was 20 mu M. It is concluded that these metabolites may contribute to the carcinogenicity of OPP and sodium o-pheny lphenolate (SOPP) observed in rats, by generating reactive oxygen species ( ROS) through their redox cycling properties.