Reporter gene assays as screening tools to assess the endocrine disrupting potencies of 20 pesticides

Poster (2009)

LC-MS/MS multi-analyte method for mycotoxin determination in food supplements

in Food Additives & Contaminants (2009), 26(6), 885-895

A multi-analyte method for the liquid chromatography-tandem mass spectrometric determination of mycotoxins in food supplements is presented. The analytes included A and B trichothecenes (nivalenol ... [more ▼]

A multi-analyte method for the liquid chromatography-tandem mass spectrometric determination of mycotoxins in food supplements is presented. The analytes included A and B trichothecenes (nivalenol, deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxyvalenol, neosolaniol, fusarenon-X, diacetoxyscirpenol, HT-2 toxin and T-2 toxin), aflatoxins (aflatoxin-B-1, aflaxoin-G(1) and aflatoxin-G(2)). Alternaria toxins (alternariol, alternariol methyl ether and altenuene), fumonisins (fumonisin-B-1, fumonisin-B-2 and fumonisin-B-3), ochratoxin A, zearalenone, beauvericin and sterigmatocystin. Optimization of the stimulataneous extraction of these toxins and the sample pretreatment procedure, as well as method validation were performed on maca (Lepidium meyenii) food supplements. The results indicated that the solvent mixture ethyl acetate/formic acid (95:5, v/v) n-hexane was applied as partial clean-up step to remove excess of co-extracted non-polar components. Further clean-up was performed on Oasis HLB(TM) cartidges. Samples were analysed using an Acquity UPLC system coupled to a Micromass Quattro Micro triple quadrupole mass spectrometer equipped with an electrospray interface operated in the positive-ion mode. Limits of detection and quantification were in the range of 0.3-30 ng g(-1) and 1-100 ng g(-1), respectively. Recovery yields were above 60% for most of the analytes, except for different food supplements such as soy (Glycine max) isoflavones, St John's wort (Hypericum perforatum), garlic (Allium sativum), Ginkgo biloba, and black radish (Raphanus niger) demonstrated the general applicability of the method. Due to different matrix effects observed in different food supplement samples, the standard addition approach was applied to perform correct quantitative analysis. In 56 out of 62 samples analysed, none of the 23 mycotoxins investigated was detected. Positive samples contained at least one of the toxins fumonisin-B-1, fumonisin-B-2, fumonisin-B-3 and ochratoxin A. [less ▲]

Food flavonoid aryl hydrocarbon receptor-mediated agonistic/antagonistic/synergic activities in human and rat reporter gene assays

in Analytica Chimica Acta (2009), 637

Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor mediating the adverse effects of dioxins and polycyclic aromatic hydrocarbons (PAHs). In this study, we investigated the genetic ... [more ▼]

Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor mediating the adverse effects of dioxins and polycyclic aromatic hydrocarbons (PAHs). In this study, we investigated the genetic-, time-, dose-, species- and tissue-dependent AhR-mediated agonistic/ antagonistic activities of three food flavonoids: quercetin, chrysin and genistein. To that end, four stably transfected cell lines were used in cell-based luciferase reporter gene assays: three lines were transformed with the ptKLuc vector harbouring four dioxinresponsive elements (DREs) upstream of the thymidine kinase promoter and the luciferase gene (HepG2-Luc, T-47D-Luc and H4IIE-ULg). The fourth is a patented cell line transformed with a different construct: H4IIE DR-CALUX®. Both H4IIE cells were compared for their genetic construction. Human hepatoma (HepG2-Luc) and human breast tumour (T-47D-Luc) cells were compared for tissue-dependent effects. Rat hepatoma (H4IIE-ULg) and human hepatoma (HepG2-Luc) cellswere compared for species-dependent activities.We concluded that quercetin, chrysin and genistein act in a time-, dose-, species- and tissue-specific way. For example, genistein displayed agonistic activities when exposed to rat hepatoma cells during 6h but not after 24 h. Flavonoids displayed agonistic/antagonistic activities in human breast tumour cells, depending on the exposure time, while in human hepatoma cells, only antagonistic activities of flavonoids were measured. In addition, we report, in all the cells, a synergy between an isoflavone and two food contaminants; the 2,3,7,8-tetrachlorodibenzop- dioxin and 3-methylcholanthrene, a PAH. In rat cells, this synergy occurred when cells were exposed to flavonoids and contaminant for 6h, while it was observed in human cells only after 24 h. [less ▲]

Establishing a Belgian Nutrition Society (BNS): Filling The Void

in Archives of Public Health (2009), 67

Time-, species- and tissue-dependent activity profiles of food flavonoids on the activation of the aryl hydrocarbon pathway

in van Ginkel, L. A.; Bergwerff, A. A. (Eds.) Residues of Veterinary Drugs in Foods, Proceedings of the Euroresidue VI Conference (2008, May 19)

Persistent organochlorine pollutants, dioxins and polychlorinated biphenyls

in Contaminant and Residue Analysis, Comprehensive Analytical Chemistry of Elsevier (2008)

Cell based assay dioxin screening: utilisation of three new cellular bioassays from different species and tissues

in Organohalogen Compounds (2008), 70

Development and validation of a HPLC/UV/FLD method to detect the 15 (+1) eu priority PAHs in smoke flavourings

Conference (2007, June)

Performance of quadrupole-ion-trap mass spectrometry for the analysis of furan

Poster (2007)

Development and optimisation of a sub room temperature SPME-GC-MS method for the analysis of furan in food

Poster (2007)