30126
2014
eng
45
52
1
7
article
Wageningen Academic Publishers
Wageningen
1
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Preparation of 13C-labelled cis-zearalenone and its application as internal standard in stable isotope dilution analysis
Pure U-[13C18]-labelled cis-zearalenone (cis-ZEA) has been prepared and characterised as internal standard (ISTD) for a reliable quantification of cis-ZEA in contaminated food and feed products. The cis-isomer of the naturally trans-configurated Fusarium mycotoxin zearalenone is often neglected. However, isomerisation easily occurs by exposure of ZEA to (UV-)light. Thus, the applicability of the new cis-ZEA ISTD was demonstrated in a long-term isomerisation study comparing naturally trans-ZEA-contaminated edible oil with spiked edible oil. To estimate the benefits of the newly prepared cis-ZEA ISTD, various approaches to quantify cis-ZEA by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) were compared. As a result, a significant bias was revealed if no appropriate cis-ZEA standards are used. Furthermore, the new ISTD was applied to the analysis of 15 edible oils by stable isotope dilution analysis in combination with HPLC-electrospray ionisation-MS/MS. One of the maize germ oils showed the presence of cis-ZEA above LOD (>0.3 µg/kg), whereas two out of 15 maize germ oils were found to be contaminated with trans-ZEA (range 17.0-31.0 µg/kg).
World mycotoxin journal
33076
10.3920/WMJ2013.1610
1875-0710
1875-0796
10.02.2014
Sarah Drzymala
Juliane Riedel
Robert Köppen
L.-A. Garbe
Matthias Koch
eng
uncontrolled
ZEA
eng
uncontrolled
Zearalenone
eng
uncontrolled
Isomerisation
eng
uncontrolled
Occurrence
eng
uncontrolled
Edible oil
eng
uncontrolled
SIDA
eng
uncontrolled
HPLC-MS/MS
eng
uncontrolled
Quantification
eng
uncontrolled
LC-MS/MS
Verlagsliteratur
Datei im Netzwerk der BAM verfügbar ("Closed Access")
32071
2014
eng
1972
1978
11
27
article
Soc.
Washington, DC, USA
American Chemical Society
1
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In vitro phase I metabolism of cis-zearalenone
The present study investigates the in vitro phase I metabolism of cis-zearalenone (cis-ZEN) in rat liver microsomes and human liver microsomes. cis-ZEN is an often ignored isomer of the trans-configured Fusarium mycotoxin zearalenone (trans-ZEN). Upon the influence of (UV-) light, trans-ZEN isomerizes to cis-ZEN. Therefore, cis-ZEN is also present in food and feed. The aim of our study was to evaluate the in vitro phase I metabolism of cis-ZEN in comparison to that of trans-ZEN. As a result, an extensive metabolization of cis-ZEN is observed for rat and human liver microsomes as analyzed by HPLC-MS/MS and high-resolution MS. Kinetic investigations based on the substrate depletion approach showed no significant difference in rate constants and half-lives for cis- and trans-ZEN in rat microsomes. In contrast, cis-ZEN was depleted about 1.4-fold faster than trans-ZEN in human microsomes. The metabolite pattern of cis-ZEN revealed a total of 10 phase I metabolites. Its reduction products, α- and β-cis-zearalenol (α- and β-cis-ZEL), were found as metabolites in both species, with α-cis-ZEL being a major metabolite in rat liver microsomes. Both compounds were identified by co-chromatography with synthesized authentic standards. A further major metabolite in rat microsomes was monohydroxylated cis-ZEN. In human microsomes, monohydroxylated cis-ZEN is the single dominant peak of the metabolite profile. Our study discloses three metabolic pathways for cis-ZEN: reduction of the keto-group, monohydroxylation, and a combination of both. Because these routes have been reported for trans-ZEN, we conclude that the phase I metabolism of cis-ZEN is essentially similar to that of its trans isomer. As trans-ZEN is prone to metabolic activation, leading to the formation of more estrogenic metabolites, the novel metabolites of cis-ZEN reported in this study, in particular α-cis-ZEL, might also show higher estrogenicity.
Chemical research in toxicology
35132
10.1021/tx500312g
0893-228X
1520-5010
27.11.2014
Sarah Drzymala
Antje Herrmann
Ronald Maul
Dietmar Pfeifer
L.-A. Garbe
Matthias Koch
eng
uncontrolled
Cis-ZEN
eng
uncontrolled
Phase I metabolism
eng
uncontrolled
LC-MS/MS
eng
uncontrolled
HRMS
eng
uncontrolled
Depletion kinetics
Verlagsliteratur
Datei im Netzwerk der BAM verfügbar ("Closed Access")
33067
2015
eng
3489
3497
12
407
article
Springer
Berlin
1
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--
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Automated solid-phase extraction coupled online with HPLC-FLD for the quantification of zearalenone in edible oil
Established maximum levels for the mycotoxin zearalenone (ZEN) in edible oil require monitoring by reliable analytical methods. Therefore, an automated SPE-HPLC online system based on dynamic covalent hydrazine chemistry has been developed. The SPE step comprises a reversible hydrazone formation by ZEN and a hydrazine moiety covalently attached to a solid phase. Seven hydrazine materials with different properties regarding the resin backbone, pore size, particle size, specific surface area, and loading have been evaluated. As a result, a hydrazine-functionalized silica gel was chosen. The final automated online method was validated and applied to the analysis of three maize germ oil samples including a provisionally certified reference material. Important performance criteria for the recovery (70–120 %) and precision (RSDr <25 %) as set by the Commission Regulation EC 401/2006 were fulfilled: The mean recovery was 78 % and RSDr did not exceed 8 %. The results of the SPE-HPLC online method were further compared to results obtained by liquid&–liquid extraction with stable isotope dilution analysis LC-MS/MS and found to be in good agreement. The developed SPE-HPLC online system with fluorescence detection allows a reliable, accurate, and sensitive quantification (limit of quantification, 30 µg/kg) of ZEN in edible oils while significantly reducing the workload. To our knowledge, this is the first report on an automated SPE-HPLC method based on a covalent SPE approach.
Analytical and bioanalytical chemistry
36146
10.1007/s00216-015-8541-5
1618-2642
1618-2650
22.04.2015
Sarah Drzymala
S. Weiz
J. Heinze
S. Marten
Carsten Prinz
Annett Zimathies
L.-A. Garbe
Matthias Koch
eng
uncontrolled
Dynamic covalent hydrazine chemistry (DCHC)
eng
uncontrolled
Maize germ oil
eng
uncontrolled
Food
eng
uncontrolled
Mycotoxin
eng
uncontrolled
ZEA
eng
uncontrolled
Isomerisation
eng
uncontrolled
Occurrence
eng
uncontrolled
Edible oil
eng
uncontrolled
SIDA
eng
uncontrolled
LC-MS/MS
eng
uncontrolled
Quantification
Verlagsliteratur
Datei im Netzwerk der BAM verfügbar ("Closed Access")
34167
2015
eng
10
12
105
article
Elsevier
Oxford [u.a.]
1
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Estrogenicity of novel phase I and phase II metabolites of zearalenone and cis-zearalenone
Zearalenone and its cis-isomer, cis-zearalenone, are nonsteroidal mycotoxins that elicit an estrogenic response upon binding to the estrogen receptor. This study compares the estrogenicity of eleven congeners including novel metabolites as 15-OH-zearalenone, zearalenone-14-sulfate, α-cis-zearalenol and β-cis-zearalenol using the E-Screen assay. Overall, a change in the configuration from trans to cis retains significant estrogenic activity. In contrast, alterations of the aromatic moiety including hydroxylation and sulfation showed a markedly decreased estrogenicity when compared to zearalenone.
Toxicon
37296
10.1016/j.toxicon.2015.08.027
0041-0101
1879-3150
17.09.2015
Sarah Drzymala
J. Binder
Antje Brodehl
M. Penkert
M. Rosowski
L.-A. Garbe
Matthias Koch
eng
uncontrolled
Zearalenone
eng
uncontrolled
Mycotoxin
eng
uncontrolled
MCF-7
eng
uncontrolled
E-screen assay
eng
uncontrolled
Estrogenicity
eng
uncontrolled
Isomerization
Verlagsliteratur
Datei im Netzwerk der BAM verfügbar ("Closed Access")