Delphinidin protects colon carcinoma cells against the genotoxic effects of the mycotoxin altertoxin II. (1st March 2018) - Aichinger, Georg
Graphical abstract: Highlights: The mycotoxin altertoxin II (ATX-II) induces DNA strand breaks in HT-29 cells. The anthocyanidin delphinidin (DEL) suppresses this genotoxicity of ATX-II. The presence of DEL diminishes detectable ATX-II levels. Potential contribution of degradation products of DEL. Abstract: Alternaria spp. are ubiquitous molds that are able to produce toxic secondary metabolites which may contaminate food globally. One of those is the mycotoxin altertoxin II (ATX-II), a genotoxic and mutagenic compound. In recent years, different flavonoids that may co-occur with mycotoxins in food were demonstrated to temper toxic effects of molds, mostly through their anti-oxidant properties. Thus, in this study, we assessed the influence of the berry anthocyanidin delphinidin on the toxicity of ATX-II in HT-29 colon carcinoma cells. We performed coupled SRB/WST-1 cytotoxicity assays which revealed only weak antagonistic interactions, and single-cell gel electrophoresis ("comet") assays, where we observed a potent protective effect of delphinidin on the DNA-damaging properties of ATX-II. Furthermore, we investigated the mechanism for this interaction. In the DCF assay delphinidin was found to reduce intracellular oxidative stress levels, which might contribute partly to the latter protection. However, LC-MS experiments showed that co-incubation of the mycotoxin with either delphinidin or its potential degradation product phloroglucinol aldehyde significantly decreased ATX-II concentrations in aqueous solutions, indicating that a direct chemical reaction of ATX-II with these components is likely responsible for the observed loss of toxicity. Our results indicate that delphinidin − and possibly other anthocyanins as well − might play a role in the protection of the gut from Alternaria- induced genotoxicity.