Protective effects of isothiocyanates towards N‐nitrosamine‐induced 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 towards N-nitrosamine-induced DNA damage in the single-cell gel electrophoresis (SCGE)/HepG2 assay. None of the isothiocyanates (ITCs) concentrations tested in the presence or absence of formamidopyrimidine-DNA glycosylase (Fpg) caused DNA damage per se. Combined treatments of HepG2 cells with phenethyl isothiocyanate (PEITC), allyl isothiocyanate (AITC) or indol-3-carbinol (I3C) and N-nitrosopyrrolidine (NPYR) or N-nitrosodimethylamine (NDMA) reduced the genotoxic effects of the N-nitrosamines in a dose-dependent manner. The protective effect of the three ITCs tested was higher towards NPYR-induced oxidative DNA damage than against NDMA. The greatest protective effect towards NPYR-induced oxidative DNA damage was shown by I3C (1 microM, 79%) and by PEITC (1 microM, 67%) and I3C (1 microM, 61%) towards NDMA (in presence of Fpg enzyme). However, in absence of Fpg enzyme, AITC (1 microM, 72%) exerted the most drastic reduction towards NPYR-induced oxidative DNA damage, and PEITC (1 microM, 55%) towards NDMA. Our results indicate that ITCs protect human-derived cells against the DNA damaging effect of NPYR and NDMA, two carcinogenic compounds that occur in the environment.

Antimutagenic Effect of Phenethyl Isothiocyanate

“…In contrast to findings of Arranz et al (31), who described the PEITC-caused reduction of SSB induced by N-nitrosamine in HepG2 cells, we have not seen any PEITC-caused reduction of SSB induced by IQ. Our results are in accordance with findings of García et al (44), who found a weak protective effect of PEITC towards N-nitrosodibutylamine or N-nitrosopiperidine oxidative DNA damage in the single cell gel electrophoresis (SCGE)/HepG2 assay.…”

“…Modulation of the clastogenic effect of mitomycine C and cyclophosphamide by PEITC was detected in bone marrow cells of mice (30). The protective effect of isothiocyanates towards N-nitrosamine induced DNA damage was proved in HepG2 cells by the single-cell gel electrophoresis assay (31).…”

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

“…In our previous studies, the protective effect of ITCs alone towards Nnitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) was evaluated (Arranz et al, 2006). Our results showed that the protective effects of ITCs tested were higher towards NPYR induced oxidative DNA damage than against NDMA.…”

“…I3C exerted greater inhibition on coumarin hydroxylase activity than PEITC. The antimutagenic effects of cruciferous vegetables extracts against food N-nitrosamines have been previously evaluated in our laboratory (Ikken et al, 1998) as well as the protective effect of PEITC, AITC and I3C towards NDMA or NPYR-induced oxidative DNA damage (Arranz et al, 2006). The results of theses studies reported that broccoli extracts exhibited strong antimutagenic effects against NDBA (43.5%) and NPIP (39%) by the Ames test.…”

“…The induction of DNA damage by PEITC, AITC, I3C and vitamin C alone in human HepG2 cells was also evaluated in our laboratory. None of the ITCs (0.1, 0.5 and 1 μM) or vitamin C (10 μM) concentrations tested caused DNA damage per se (Arranz et al, 2006(Arranz et al, , 2007. Figure 1 shows the effect of PEITC alone (A) or in combination with vitamin C (B) on NPIP or NDBAinduced oxidative DNA damage in HepG2 cells incubated with Fpg enzyme.…”