The anticlastogenicity of β-carotene evaluated on human hepatoma cells

Abstract The efficiency of β-carotene as a modulatory agent against clastogenicity induced by a cyclophosphamide (CPA), an indirect-acting mutagen, and mitomycin C (MMC), a direct-acting mutagen, was evaluated in human hepatoma cells (Hep G2) using three different treatment regimes. Six doses of β-carotene, 0.25, 0.5, 1.0, 2.0, 4.0 and 6.0 μM, were tested as pre-treatment, simultaneous treatment and pre- + simultaneous treatment. Since these cells are able to activate mutagens without any exogenous metabolizing system (S9 mix), some problems related to the use of S9 mix were eliminated. The data obtained show a statistically significant decrease in the frequency of micronuclei (MN) induced by CPA when the cells were treated with β-carotene, for all treatments, and no effect of this provitamin on the clastogenicity of MMC was found. These results reinforce the anticlastogenicity of β-carotene showing and its action is independent of the treatment regime used. On the ther hand, the fact that β-carotene had a protective action only on CPA-induced MN suggests an effect on activation of the promutagen and emphasizes the important utility of cell lines capable of metabolizing chemical mutagens, in such basic studies.