Genotoxicity is modulated by ascorbic acid: Studies using the wing spot test in Drosophila

Abstract

The ability of ascorbic acid (Vitamin C) to modulate the genotoxic action of several mutagens was investigated in the wing spot test of Drosophila melanogaster. In this assay, 3-day-old transheterozygous larvae for the multiple wing hairs ( mwh, 3-0.3) and flare ( flr, 3-38.8) genes were treated with three reference mutagenic compounds, namely cobalt chloride (CoCl 2), 4-nitroquinoline 1-oxide (4-NQO) and potassium dichromate (K 2Cr 2O 7). The results obtained show that the three reference mutagens tested were clearly genotoxic in the Drosophila wing somatic mutation and recombination test (SMART). None of the three concentrations tested of ascorbic acid (25, 75 and 250 mM) induced significant increases in the frequency of the mutant clones recorded. When co-treatment experiments with ascorbic acid were carried out, different results were found. Thus, ascorbic acid was effective in reducing the genotoxicity of K 2Cr 2O 7 virtually to the control level; on the contrary, it did not show any antigenotoxic effect on the genotoxicity of 4-NQO. Finally, co-treatments with CoCl 2 and ascorbic acid show a significant increase in the frequency of mutant clones over the values obtained with CoCl 2 alone.