CONTRIBUTION OF PHENOLS, QUINONES AND REACTIVE OXYGEN SPECIES TO THE MUTAGENICITY OF WHITE GRAPE JUICE IN THE AMES TEST

The purpose of this study was to evaluate the role of phenols, quinone s and reactive oxygen species in the mutagenicity of white grape juice in the Ames mutagenicity test. Mutagenicity was markedly suppressed b y reduced glutathione but was not influenced by superoxide dismutase o r catalase. In the presence of grape polyphenol oxidase, the mutagenic ity of grape juice was markedly increased. When hepatic cytosol from A roclor 1254-induced rats, supplemented with a reduced nicotinamide ade nine dinucleotide phosphate-generating system, served as an activation system, an increase in the mutagenicity of grape juice was observed. The cytosol-induced mutagenicity of grape juice was attenuated in the presence of superoxide dismutase, catalase and glutathione. It is conc luded that polyphenol oxidase-catalysed oxidation of phenolic compound s generates genotoxic species that are, at least partly, responsible f or the mutagenicity of grape juice. In the presence of hepatic cytosol , one-electron reduction of grape juice quinones leads to the producti on of reactive oxygen species resulting in an increase in the mutageni c response. Copyright (C) 1996 Published by Elsevier Science Ltd