EFFECT OF EUGENOL ON THE GENOTOXICITY OF ESTABLISHED MUTAGENS IN THE LIVER

The influence of in vivo treatment with eugenol on established mutagen s was studied to determine whether eugenol has antigenotoxic potential . The effects of eugenol in rats was investigated in the unscheduled D NA synthesis (UDS) assay with established mutagens and the Salmonella typhimurium mutagenicity assay. In addition, the effect of in vitro tr eatment with eugenol on benzo[a]pyrene (B[a]P)-induced genotoxicity in human hepatoma cell line Hep G2 was investigated in the single-cell g el electrophoresis assay. The mutagenicity of B[a]P in the S. typhimur ium mutagenicity assay was lower in liver S-9 fractions prepared from rats treated with eugenol orally (1000 mg/kg body weight) than in live r S-9 fractions from control rats. Incubation of liver S-9 fractions f rom eugenol-treated rats with dimethylbenzanthracene (DMBA) had no ant imutagenic effect. Eugenol did not modify UDS activity in hepatocytes isolated from rats pretreated with eugenol orally after exposure of th ese cells in vitro to DMBA and aflatoxin B-1. Four different treatment schemes of combinations of B[a]P and eugenol were examined in Hep G2 cells: pre-treatment with eugenol; simultaneous treatment with eugenol and B[a]P; a combination of these (pretreatment/simultaneous treatmen t); and post-treatment with eugenol. An increase in the genotoxicity o f B[a]P was found in Hep G2 cells. No effect of eugenol on the genotox icity of B[a]P was found with the pre- and post-treatments. It is conc luded that the effect of eugenol on genotoxicity induced by establishe d mutagens is not univocal: in vivo treatment of rats with eugenol res ulted in a reduction of the mutagenicity of B[a]P in the S. typhimuriu m mutagenicity assay, while in the UDS assay no effect of eugenol was found. In vitro treatment of cultured cells with eugenol resulted in a n increase in genotoxicity of B[a]P. These findings indicate that ther e is only limited support for the antigenotoxic potential of eugenol i n vivo.