title: Deoxynivalenol-sulfates: identification and quantification of novel conjugated (masked) mycotoxins in wheat.
abstract: We report the identification of deoxynivalenol-3-sulfate and deoxynivalenol-15-sulfate as two novel metabolites of the trichothecene mycotoxin deoxynivalenol in wheat. Wheat ears which were either artificially infected with Fusarium graminearum or directly treated with the major Fusarium toxin deoxynivalenol (DON) were sampled 96 h after treatment. Reference standards, which have been chemically synthesized and confirmed by NMR, were used to establish a liquid chromatography-electrospray ionization (LC-ESI)-MS/MS-based "dilute and shoot" method for the detection, unambiguous identification, and quantification of both sulfate conjugates in wheat extracts. Using this approach, detection limits of 0.003 mg/kg for deoxynivalenol-3-sulfate and 0.002 mg/kg for deoxynivalenol-15-sulfate were achieved. Matrix-matched calibration was used for the quantification of DON-sulfates in the investigated samples. In DON-treated samples, DON-3-sulfate was detected in the range of 0.29-1.4 mg/kg fresh weight while DON-15-sulfate concentrations were significantly lower (range 0.015-0.061 mg/kg fresh weight). In Fusarium-infected wheat samples, DON-3-sulfate was the only detected sulfate conjugate (range 0.022-0.059 mg/kg fresh weight). These results clearly demonstrate the potential of wheat to form sulfate conjugates of DON. In order to test whether sulfation is a detoxification reaction in planta, we determined the ability of the sulfated DON derivatives to inhibit in vitro protein synthesis of wheat ribosomes. The results demonstrate that both DON-sulfates can be regarded as detoxification products. DON-15-sulfate was about 44× less inhibitory than the native toxin, and no toxicity was observed for DON-3-sulfate in the tested range.
authors.affiliation: Center for Analytical Chemistry, Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Str. 20, 3430, Tulln, Austria, benedikt.warth@boku.ac.at.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Warth
authors.forename: Philipp
authors.initials: P
authors.lastname: Fruhmann
authors.forename: Gerlinde
authors.initials: G
authors.lastname: Wiesenberger
authors.forename: Bernhard
authors.initials: B
authors.lastname: Kluger
authors.forename: Bojan
authors.initials: B
authors.lastname: Sarkanj
authors.forename: Marc
authors.initials: M
authors.lastname: Lemmens
authors.forename: Christian
authors.initials: C
authors.lastname: Hametner
authors.forename: Johannes
authors.initials: J
authors.lastname: Fröhlich
authors.forename: Gerhard
authors.initials: G
authors.lastname: Adam
authors.forename: Rudolf
authors.initials: R
authors.lastname: Krska
authors.forename: Rainer
authors.initials: R
authors.lastname: Schuhmacher
mesh_terms: D002138:Calibration; D002853:Chromatography, Liquid; D005506:Food Contamination / Q000032:analysis*; D005670:Fusarium / Q000378:metabolism*; D015394:Molecular Structure; D009183:Mycotoxins / Q000032:analysis* / Q000633:toxicity; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D014255:Trichothecenes / Q000032:analysis* / Q000633:toxicity; D014908:Triticum / Q000737:chemistry* / Q000382:microbiology
chemical_list: D009183:Mycotoxins; D014255:Trichothecenes; C000601824:deoxynivalenol-15-sulfate