title: Genotoxicity of aminohydroxynaphthoquinones in bacteria, yeast, and Chinese hamster lung fibroblast cells.
abstract: There are few studies on the biological activity of aminohydroxy derivates of 1,4-naphthoquinone (1,4-NQ) on prokaryotic and eukaryotic cells. We determined the mutagenic activity of 5-amino-8-hydroxy-1,4-naphthoquinone (ANQ) and 5-amino-2,8-dihydroxy-1,4-naphthoquinone (ANQ-OH) as compared to the unsubstituted 1,4-NQ in Salmonella/microsome assay. Potential mutagenic and recombinogenic effects and cytotoxicity were analyzed in haploid and diploid cultures of the yeast Saccharomyces cerevisiae. In Salmonella/microsome assay, 1,4-NQ was not mutagenic, whereas aminohydroxynaphthoquinones were weakly mutagenic in TA98 and TA102 strains. In haploid yeast in stationary growth phase (STAT), mutagenic response was only observed for the hom3 locus at the highest dose. In diploid yeast, aminohydroxynaphthoquinones did not induce any recombinogenic events, but 1,4-NQ was shown to be a recombinogenic agent. These results suggest that aminohydroxynaphthoquinones are weak mutagenic agents only in prokaryotic cells. The cytotoxicity of 1,4-NQ in yeast stationary cells was more significant in diploid cells as compared to that observed in haploid cells. However, ANQ and ANQOH were slightly cytotoxic in all treatments. Genotoxicity of these naphthoquinone compounds was also determined in V79 Chinese hamster lung fibroblast cells using standard Comet, as well as modified Comet assay with the bacterial enzymes formamidopyrimidine DNA-glycosylase (FPG) and endonuclease III (ENDOIII). Both 1,4-NQ and ANQ induced pronounced DNA damage in the standard Comet assay. The genotoxic effect of ANQ-OH was observed only at the highest dose. In presence of metabolic activation all substances showed genotoxic effects on V79 cells. Post-treatment of V79 cells with ENDOIII and FPG proteins did not have a significant effect on ANQ-OH-induced oxidative DNA damage as compared to standard alkaline Comet assay. However, all naphthoquinones were genotoxic in V79 cells in the presence of metabolic activation and post-treatment with enzymes, indicating that all compounds induced oxidative DNA damage in V79 cells. Our data suggest that aminohydroxynaphthoquinone pro-oxidant activity, together with their capability of DNA intercalation, have an important role in mutagenic and genotoxic activities.
authors.affiliation: Laboratório de Genotoxicidade-Instituto Royal-Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Luis Fernando
authors.initials: LF
authors.lastname: da Costa Medina
authors.forename: Cassiana Macagnan
authors.initials: CM
authors.lastname: Viau
authors.forename: Dinara Jaqueline
authors.initials: DJ
authors.lastname: Moura
authors.forename: Jenifer
authors.initials: J
authors.lastname: Saffi
authors.forename: Valter
authors.initials: V
authors.lastname: Stefani
authors.forename: Adriano
authors.initials: A
authors.lastname: Brandelli
authors.forename: João Antonio Pêgas
authors.initials: JA
authors.lastname: Henriques
mesh_terms: D000818:Animals; D001711:Biotransformation; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004249:DNA Damage; D004260:DNA Repair; D005347:Fibroblasts / Q000187:drug effects; D009153:Mutagens / Q000633:toxicity*; D009285:Naphthoquinones / Q000633:toxicity*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000235:genetics; D013329:Structure-Activity Relationship
chemical_list: D009153:Mutagens; D009285:Naphthoquinones