title: Protective effects of isothiocyanates alone or in combination with vitamin C towards N-nitrosodibutylamine or N-nitrosopiperidine-induced oxidative DNA damage in the single-cell gel electrophoresis (SCGE)/HepG2 assay.
abstract: The aim of this study was to investigate the protective effect of isothiocyanates alone or in combination with vitamin C towards N-nitrosodibutylamine (NDBA) or N-nitrosopiperidine (NPIP)-induced oxidative DNA damage in the single cell gel electrophoresis (SCGE)/HepG2 assay. Phenethyl isothiocyanate (PEITC) and indole-3-carbinol (I3C) alone showed a weak protective effect towards NDBA (0.1 microm, 26-27%, respectively) or NPIP (1 microm, 26-28%, respectively)-induced oxidative DNA damage. Allyl isothiocyanate (AITC) alone did not attenuate the genotoxic effect provoked by NDBA or NPIP. In contrast, HepG2 cells simultaneously treated with PEITC, I3C and AITC in combination with vitamin C showed a stronger inhibition of oxidative DNA-damage induced by NDBA (0.1 microm, 67%, 42%, 32%, respectively) or NPIP (1 microm, 50%, 73%, 63%, respectively) than isothiocyanates (ITCs) alone. One feasible mechanism by which ITCs alone or in combination with vitamin C exert their protective effects towards N-nitrosamine-induced oxidative DNA damage could be by the inhibition of their cytochrome P450 dependent bioactivation. PEITC and I3C strongly inhibited the p-nitrophenol hydroxylation (CYP2E1) activity (0.1 microm, 66-50%, respectively), while the coumarin hydroxylase (CYP2A6) activity was slightly reduced (0.1 microm, 25-37%, respectively). However, the ethoxyresorufin O-deethylation (CYP1A1) activity was only inhibited by PEITC (1 microm, 55%). The results indicate that PEITC and I3C alone or PEITC, I3C and AITC in combination with vitamin C protects human-derived cells against the oxidative DNA damaging effects of NDBA and NPIP, two food carcinogenic compounds.
authors.affiliation: Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: Almudena
authors.initials: A
authors.lastname: García
authors.forename: Ana I
authors.initials: AI
authors.lastname: Haza
authors.forename: Nuria
authors.initials: N
authors.lastname: Arranz
authors.forename: Joseph
authors.initials: J
authors.lastname: Rafter
authors.forename: Paloma
authors.initials: P
authors.lastname: Morales
mesh_terms: D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors / Q000378:metabolism; D001205:Ascorbic Acid / Q000494:pharmacology*; D002273:Carcinogens / Q000633:toxicity*; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D020552:Comet Assay / Q000379:methods; D019363:Cytochrome P-450 CYP1A1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D065637:Cytochrome P-450 CYP2A6; D019392:Cytochrome P-450 CYP2E1 / Q000378:metabolism; D065691:Cytochrome P-450 CYP2E1 Inhibitors; D053960:DNA Breaks / Q000187:drug effects*; D043382:DNA-Formamidopyrimidine Glycosylase / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D017879:Isothiocyanates / Q000494:pharmacology*; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009602:Nitrosamines / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects*
chemical_list: D016588:Anticarcinogenic Agents; D002273:Carcinogens; D065691:Cytochrome P-450 CYP2E1 Inhibitors; D004791:Enzyme Inhibitors; D007211:Indoles; D017879:Isothiocyanates; D009602:Nitrosamines; C002743:N-nitrosopiperidine; C058305:phenethyl isothiocyanate; C012279:dibutylnitrosamine; C004471:allyl isothiocyanate; C016517:indole-3-carbinol; D006899:Mixed Function Oxygenases; D019392:Cytochrome P-450 CYP2E1; D001189:Aryl Hydrocarbon Hydroxylases; C585710:CYP2A6 protein, human; D019363:Cytochrome P-450 CYP1A1; D065637:Cytochrome P-450 CYP2A6; D043382:DNA-Formamidopyrimidine Glycosylase; D001205:Ascorbic Acid