Contribution of reactive oxygen species (ROS) to genotoxicity of nitrobenzene on V. faba.

Nitrobenzene is an important organic intermediate widely used in industry that can be hazardous to the environment. In our previous study, nitrobenzene showed genotoxic effect on soybean and tobacco plants at concentrations in the culture medium higher than 10 mg/L. The genotoxicity of nitrobenzene has been hypothesized to be multifactorial and reflective of the generation of free radicals; however, the mechanism has not been fully elucidated. The aim of this study was to investigate the relationship between the induction of genotoxicity and the production of free radicals in young seedlings of V. faba exposed to nitrobenzene, nitrobenzene + Vitamin C, and the controls (distilled water or Vitamin C). Micronucleus and chromosome aberration assays performed on root and leaf tissue of V. faba seedlings exposed to nitrobenzene (25 mg/L) demonstrated genotoxic effects which were partly reduced by Vitamin C at 25 mg/L. Increases in lipid peroxidase, O2•-, H2O2, superoxide dismutase and catalase activities were also observed in these tissues along with an attenuation of their induction by Vitamin C. Concomitant occurrence of genotoxicity and the generation of free radicals that are attenuated in the presence of Vitamin C, a scavenger of cellular free radicals, indicate that reactive oxygen species may contributes to genotoxicity of nitrobenzene in V. faba. These results are valuable for further understanding the genotoxicity mechanism of nitrobenzene.