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<div class="csl-entry">Pirker, K. F. (2005). <i>EPR investigations of free radical formation during oxidation of some plant and fungal tissues and naturally-occurring phenols</i> [Dissertation, Technische Universität Wien]. reposiTUm. https://resolver.obvsg.at/urn:nbn:at:at-ubtuw:1-19091</div>
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The generation of free radicals by cell disruption in different biological materials was investigated in the presence of spin traps by Electron Paramagnetic Resonance (EPR). Pro-oxidative activity of carrot and herb samples was observed with the spin traps PBN and 4-POBN.<br />Carbon-centred radicals were detected with DMPO derivatives, TRAZON and PEPO, .OH radicals were also trapped with DEPMPO and DPPMPO as spin traps. Specific identification of the free radical from mushroom as the N-t-butylhydronitroxide radical was possible with this range of spin traps. Oxidation of four specific phenolic compounds (kaempferol, luteolin, rosmarinic acid, carnosic acid) under different conditions resulted in different EPR spectra which were interpreted. Various structural suggestions have been formulated. The chosen oxidation conditions were relatively mild but all components could be easily oxidised, consistent with their excellent abilities to scavenge free radicals by donating hydrogen atoms. The stability of the detected radicals was quite long with at least 6 min. lifetime. The structures of kaempferol and CA changed by oxidation and their metabolites may be of relevance in the antioxidant mechanism. In contrast, the structures of RA and luteolin remained intact, and they are likely to be able to be redox-cycled. Information gained in this work could serve as basis for further investigations of food preparation or even the chewing process.<br />Furthermore the radical formation of relevant phenolic compounds was detected under physiologically relevant conditions at pH 7 and the formation of stable free radicals may be relevant to questions relating to their use as health products or pro-oxidative and toxic substances.
de
dc.language
English
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dc.language.iso
en
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dc.rights.uri
http://rightsstatements.org/vocab/InC/1.0/
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dc.subject
Kräuter
de
dc.subject
Karotte
de
dc.subject
Oxidation
de
dc.subject
Freies Radikal
de
dc.subject
Elektronenspinresonanzspektroskopie
de
dc.subject
Champignon
de
dc.subject
Polyphenole
de
dc.title
EPR investigations of free radical formation during oxidation of some plant and fungal tissues and naturally-occurring phenols
en
dc.type
Thesis
en
dc.type
Hochschulschrift
de
dc.rights.license
In Copyright
en
dc.rights.license
Urheberrechtsschutz
de
dc.contributor.affiliation
TU Wien, Österreich
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dc.rights.holder
Katharina Franziska Pirker
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tuw.version
vor
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tuw.thesisinformation
Technische Universität Wien
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dc.contributor.assistant
Stolze, Klaus
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tuw.publication.orgunit
E164 - Institut für Chemische Technologien und Analytik