TY - JOUR A1 - Maul, Ronald A1 - Warth, B. A1 - Schebb, N.H. A1 - Krska, R. A1 - Koch, Matthias A1 - Sulyok, M. T1 - In vitro glucuronidation kinetics of deoxynivalenol by human and animal microsomes and recombinant human UGT enzymes N2 - The mycotoxin deoxynivalenol (DON), formed by Fusarium species, is one of the most abundant mycotoxins contaminating food and feed worldwide. Upon ingestion, the majority of the toxin is excreted by humans and animal species as glucuronide conjugate. First in vitro data indicated that DON phase II metabolism is strongly species dependent. However, kinetic data on the in vitro metabolism as well as investigations on the specific enzymes responsible for DON glucuronidation in human are lacking. In the present study, the DON metabolism was investigated using human microsomal fractions and uridine-diphosphoglucuronyltransferases (UGTs) as well as liver microsomes from five animal species. Only two of the twelve tested human recombinant UGTs led to the formation of DON glucuronides with a different regiospecificity. UGT2B4 predominantly catalyzed the formation of DON-15-O-glucuronide (DON-15GlcA), while for UGT2B7 the DON-3-O-glucuronide (DON-3GlcA) metabolite prevailed. For human UGTs, liver, and intestinal microsomes, the glucuronidation activities were low. The estimated apparent intrinsic clearance (Clapp,int) for all human UGT as well as tissue homogenates was <1 mL/min mg protein. For the animal liver microsomes, moderate Clapp,int between 1.5 and 10 mL/min mg protein were calculated for carp, trout, and porcine liver. An elevated glucuronidation activity was detected for rat and bovine liver microsomes leading to Clapp,int between 20 and 80 mL/min mg protein. The obtained in vitro data points out that none of the animal models is suitable for estimating the human DON metabolism with respect to the metabolite pattern and formation rate. KW - Deoxynivalenol KW - Glucuronidation KW - Uridine-diphosphoglucuronyltransferases (UGT) KW - Human recombinant UGT KW - Trichothecene KW - Phase II metabolism PY - 2015 DO - https://doi.org/10.1007/s00204-014-1286-7 SN - 0340-5761 SN - 1432-0738 VL - 89 IS - 6 SP - 949 EP - 960 PB - Springer CY - Berlin ; Heidelberg [u.a.] AN - OPUS4-33204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schloß, Svenja A1 - Koch, Matthias A1 - Rohn, S. A1 - Maul, R. T1 - Development of a SIDA-LC-MS/MS method for the determination of phomopsin A in legumes N2 - A novel method for the determination of phomopsin A (1) in lupin flour, pea flour, and bean flour as well as whole lupin plants was established based on stable isotope dilution assay (SIDA) LC-MS/MS using 15N6-1 as an isotopically labeled internal standard. Artificially infected samples were used to develop an optimized extraction procedure and sample pretreatment. The limits of detection were 0.5–1 µg/kg for all matrices. The limits of quantitation were 2–4 µg/kg. The method was used to analyze flour samples generated from selected legume seeds and lupin plant samples that had been inoculated with Diaporthe toxica and two further fungal strains. Finally, growing lupin plants infected with D. toxica were investigated to simulate a naturally in-field mycotoxicosis. Toxin levels of up to 10.1 µg/kg of 1 were found in the pods and 7.2 µg/kg in the stems and leaves. KW - Diaporthe toxica KW - Stable isotope dilution assay KW - Isotopic labeled internal standard KW - Legume contamination PY - 2015 DO - https://doi.org/10.1021/acs.jafc.5b04792 SN - 0021-8561 SN - 1520-5118 VL - 63 IS - 48 SP - 10543 EP - 10549 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-35071 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -