Purpose: This study was designed to investigate the effects of antioxidants on mitomycin C (MMC) induced sister chromatid exchanges (SCE) and micronuclei (MN). Material and Methods: The action of vitamins C (10-4 M), E (10-6 M) and β-carotene (10-6 M) on the genotoxic activity of mitomycin C (10-7 M) was evaluated in cultured human lymphocytes of five donors with the help of SCE and MN frequencies. Results: It was found that SCE and MN levels were significantly increased by MMC. The presence of vitamins C, E and β-carotene caused a significant reduction in the numbers of SCE and MN induced by MMC when used separately, but no antioxidant effect of β-carotene was observed in MMC-induced MN frequency. On the other hand, in triple combinations of vitamins C, E and β-carotene and MMC. MMC-induced SCE and MN frequencies were reduced significantly (22.02% - 24.04% for SCEs and 31.91% - 57.55% for MN). Conclusion: These results indicated that the combinations of vitamins C, E and β-carotene can modify the DNA damaging effect of the carcinogens and act as biological antioxidants under in vitro conditions
