Binary and tertiary combination of alternariol, 3-acetyl-deoxynivalenol and 15-acetyl-deoxynivalenol on HepG2 cells: Toxic effects and evaluation of degradation products

Fungi producers of mycotoxins are able to synthesize more than one toxin. Alternariol (AOH) is one of the mycotoxins produced by several Alternaria species, the most common one being Alternaria alternata. The toxins 3-Acetyl-deoxynivalenol (3-ADON) and 15-Acetyl-deoxynivalenol (15-ADON) are acetylated forms of deoxynivalenol (DON) produced by Fusarium graminearum. In the present work it is determined and evaluated the toxic effects of binary and tertiary combination treatment of HepG2 cells with AOH, 3-ADON and 15-ADON, by using the MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide), to subsequently apply the isobologram method and elucidate if the mixtures of these mycotoxins produced synergism, antagonism or additive effect; and lastly, to analyze mycotoxins conversion into metabolites produced and released by HepG2 cells after applying the treatment conditions by liquid chromatography tandem mass spectrometry (LC-MS/MS) equipment and extracted from culture media. HepG2 cells were treated at different concentrations over 24, 48 and 72h. IC50 values detected at all times assayed, ranged from 0.8 to >25μM in binary combinations; while in tertiary it ranged from 7.5 to 12μM. Synergistic, antagonism or additive effect detected in the mixtures of these mycotoxins was different depending on low or high concentration. Among all four mycotoxins combinations assayed, 15-ADON+3-ADON presented the highest toxic potential. At all assayed times, recoveries values oscillated depending on the time and combination studied.