Lumi-ergometrine – structural identification and occurrence in sclerotia

Merkel, Stefan; Köppen, Robert; Koch, Matthias; Emmerling, Franziska; Nehls, Irene

doi:10.1007/s12550-011-0116-5

Cited by 2 publications

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References 23 publications

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“…For example, light degradation processes give rise to the formation of lumi EAs [11], which demonstrate distinctly lower toxicity than (R)-configured EAs [12]. Among foods, EAs are detected in cereals and flour-based products almost exclusively.…”

Section: Introductionmentioning

confidence: 99%

Degradation and epimerization of ergot alkaloids after baking and in vitro digestion

et al. 2012

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The degradation and epimerization of ergot alkaloids (EAs) in rye flour were investigated after baking cookies and subsequently subjecting them to an in vitro digestion model. Different steps of digestion were analyzed using salivary, gastric, and duodenal juices. The degradation and bidirectional conversion of the toxicologically relevant (R)-epimers and the biologically inactive (S)-epimers for seven pairs of EAs were determined by a HPLC method coupled with fluorescence detection. Baking cookies resulted in degradation of EAs (2-30 %) and a shift in the epimeric ratio toward the (S)-epimer for all EAs. The applied digestion model led to a selective toxification of ergotamine and ergosine, two ergotamine-type EAs. The initial percentage of the toxic (R)-epimer in relation to the total toxin content was considerably increased after digestion of cookies. Ergotamine and ergosine increased from 32 to 51 % and 35 to 55 %, respectively. In contrast, EAs of the ergotoxine type (ergocornine, α- and β-ergocryptine, and ergocristine) showed an epimeric shift toward their biologically inactive (S)-epimers. Further experiments indicated that the selective epimerization of ergotamine EAs occurs in the duodenal juice only. These results demonstrate that toxification of EAs in the intestinal tract should be taken into consideration.

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Section: Introductionmentioning

confidence: 99%

Degradation and epimerization of ergot alkaloids after baking and in vitro digestion

et al. 2012

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Localization of ergot alkaloids in sclerotia of Claviceps purpurea by matrix-assisted laser desorption/ionization mass spectrometry imaging

et al. 2016

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The fungus Claviceps purpurea produces highly toxic ergot alkaloids and accumulates these in the hardened bodies of fungal mycelium. These so-called sclerotia, or ergot bodies, replace the crop seed of infected plants, which can include numerous important food- and feedstuff such as rye and wheat. While several studies have explored details of the infection process and development of ergot bodies, little information is available on the spatial distribution of the mycotoxins in the sclerotia. Here we used matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) at a lateral resolution of 35 μm to visualize the distribution of two representative alkaloids, ergocristine and ergometrine, produced by Ecc93 and Gal 310 variants of C. purpurea, respectively, after infection of rye. To improve cryosectioning of this fragile biological material tissue with complex texture, we developed a practical embedding protocol based on cellulose polymers. The MALDI-MS images recorded from the so produced intact tissues sections revealed that ergometrine exhibited a relatively homogeneous distribution throughout the ergot body, whereas ergocristine was found to be enriched in the proximal region. This finding can be correlated to the morphological development of sclerotia as ergot alkaloids are only produced in the sphacelial stage. The ability to localize toxins and other secondary metabolites in intact sections of crop-infecting fungi with high lateral resolution renders MALDI-MSI a powerful tool for investigating biosynthetic pathways and for obtaining a deeper understanding of the parasite-host interaction. Graphical abstract Workflow for identification and spatial localization of ergot alkaloids in infected rye grains.

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Lumi-ergometrine – structural identification and occurrence in sclerotia

Cited by 2 publications

References 23 publications

Degradation and epimerization of ergot alkaloids after baking and in vitro digestion

Degradation and epimerization of ergot alkaloids after baking and in vitro digestion

Localization of ergot alkaloids in sclerotia of Claviceps purpurea by matrix-assisted laser desorption/ionization mass spectrometry imaging

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