Unraveling Interspecies Differences in the Phase I Hepatic Metabolism of Alternariol and Alternariol Monomethyl Ether: Closing Data Gaps for a Comprehensive Risk Assessment.

The Alternaria mycotoxins alternariol (AOH) and alternariol 9-O-monomethyl ether (AME) are pervasive food contaminants known to exert adverse effects in vitro, yet their toxicokinetics remain inadequately understood. Thus, this study endeavors to elucidate the qualitative and quantitative aspects of the phase I metabolism of AOH and AME. To pursue this goal, reduced nicotinamide adenine dinucleotide phosphate (NADPH)-fortified porcine, rat, and human liver microsomes were incubated for 0-10 min with AOH or AME within a concentration range of 1-100 and 1-50 μM, respectively. The decline in the parent toxin concentration was monitored via liquid chromatography coupled to tandem mass spectrometry, whereas coupling to high-resolution mass spectrometry provided insights into the composition of the arising metabolic mixture. The collected quantitative data allowed us to calculate the hepatic intrinsic clearance rates of AOH and AME, marking a notable contribution to the field. Moreover, we unveiled interspecies differences in the pattern and rate of the phase I metabolism of the investigated mycotoxins. The presented findings lay the groundwork for physiologically based toxicokinetic modeling aimed at estimating local concentrations of these mycotoxins in specific organs, enhancing our understanding of their mode of action and adverse health effects.