Comparison of animal and plant DNA-adducts after exposure to benzo(a)pyrene.

The occurrence of abnormal hypermodified nucleotides on the DNA upon xenobiotic exposure has long been considered as a characteristic of carcinogenesis and mutagenesis in animal cells. We have previously shown that DNA adducts could also be formed in plants exposed to xenobiotics in natural and controlled conditions. In this study we have compared the DNA adducts formed in different animal species and in different plants after benzo(a)pyrene (B(a)P) exposure. The main DNA adduct in mice stomach and skin correspond to the 7,8-diol 9,10-epoxide B(a)P-guanine. In liver from rat, fish and Xenopus, this adduct is detected, but is not the major one. In plants analyzed, this adduct is never formed. Ten different adducts are detected in plants. This result indicates that the metabolic pathway leading to genotoxic metabolites is different with species. In conclusion, the result suggest that risk assessment for human and environment due to genotoxic compounds should be realized using multiple species assays.