Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster , Corrensstraße 45, D-48149 Münster, Germany.
J Agric Food Chem. 2012 Oct 10;60(40):10170-8. doi: 10.1021/jf302571y. Epub 2012 Sep 28.
Glucuronides of the mycotoxin T-2 toxin and its phase I metabolite HT-2 toxin are important phase II metabolites under in vivo and in vitro conditions. Since standard substances are essential for the direct quantitation of these glucuronides, a method for the enzymatic synthesis of T-2 and HT-2 toxin glucuronides employing liver microsomes was optimized. Structure elucidation by nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry revealed that besides T-2 toxin glucuronide and HT-2 toxin 3-glucuronide also the newly identified isomer HT-2 toxin 4-glucuronide was formed. Glucuronidation of T-2 and HT-2 toxin in liver microsomes of rat, mouse, pig, and human was compared and metabolites were analyzed directly by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). A distinct, species specific pattern of glucuronidation of T-2 and HT-2 toxin was observed with interesting interindividual differences. Until recently, glucuronides have frequently been analyzed indirectly by quantitation of the aglycone after enzymatic cleavage of the glucuronides by β-glucuronidase. Therefore, the hydrolysis efficiencies of T-2 and HT-2 toxin glucuronides using β-glucuronidases from Helix pomatia, bovine liver, and Escherichia coli were compared.
真菌毒素 T-2 毒素及其 I 相代谢物 HT-2 毒素的葡萄糖醛酸结合物是体内和体外条件下的重要 II 相代谢物。由于标准物质对于这些葡萄糖醛酸结合物的直接定量至关重要，因此优化了采用肝微粒体的 T-2 和 HT-2 毒素葡萄糖醛酸结合物的酶促合成方法。通过核磁共振波谱（NMR）和质谱法的结构阐明表明，除了 T-2 毒素葡萄糖醛酸结合物和 HT-2 毒素 3-葡萄糖醛酸结合物外，还形成了新鉴定的异构体 HT-2 毒素 4-葡萄糖醛酸结合物。比较了大鼠、小鼠、猪和人肝微粒体中 T-2 和 HT-2 毒素的葡萄糖醛酸化，并通过液相色谱-串联质谱（LC-MS/MS）直接分析代谢物。观察到 T-2 和 HT-2 毒素的葡萄糖醛酸化具有明显的种属特异性模式，且个体间存在有趣的差异。直到最近，葡萄糖醛酸结合物通常通过β-葡萄糖醛酸酶对葡萄糖醛酸结合物进行酶切后分析苷元来间接分析。因此，比较了来自大蜗牛、牛肝和大肠杆菌的β-葡萄糖醛酸酶对 T-2 和 HT-2 毒素葡萄糖醛酸结合物的水解效率。
