Hadaček, Franz

[["dc.bibliographiccitation.firstpage","476"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Antioxidants"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Kubicova, Lenka"],["dc.contributor.author","Hadacek, Franz"],["dc.contributor.author","Bachmann, Gert"],["dc.contributor.author","Weckwerth, Wolfram"],["dc.contributor.author","Chobot, Vladimir"],["dc.date.accessioned","2020-12-10T18:46:56Z"],["dc.date.available","2020-12-10T18:46:56Z"],["dc.date.issued","2019"],["dc.description.sponsorship","Austrian Science Fund"],["dc.identifier.doi","10.3390/antiox8100476"],["dc.identifier.eissn","2076-3921"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/17062"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/78593"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.notes.intern","Merged from goescholar"],["dc.publisher","MDPI"],["dc.relation.eissn","2076-3921"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.title","Coordination Complex Formation and Redox Properties of Kynurenic and Xanthurenic Acid Can Affect Brain Tissue Homeodynamics"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","11830"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","International Journal of Molecular Sciences"],["dc.bibliographiccitation.lastpage","11841"],["dc.bibliographiccitation.volume","14"],["dc.contributor.author","Chobot, Vladimir"],["dc.contributor.author","Kubicova, Lenka"],["dc.contributor.author","Bachmann, Gert"],["dc.contributor.author","Hadacek, Franz"],["dc.date.accessioned","2018-11-07T09:23:55Z"],["dc.date.available","2018-11-07T09:23:55Z"],["dc.date.issued","2013"],["dc.description.abstract","Some antioxidants have been shown to possess additional pro-oxidant effects. Diverse methodologies exist for studying redox properties of synthetic and natural chemicals. The latter are substantial components of our diet. Exploration of their contribution to life-extending or -compromising effects is mandatory. Among reactive oxygen species (ROS), hydroxyl radical ((OH)-O-center dot) is the most damaging species. Due to its short half-life, the assay has to contain a specific generation system. Plants synthesize flavonoids, phenolic compounds recognized as counter-agents to coronary heart disease. Their antioxidant activities are affected by their hydroxylation patterns. Moreover, in the plant, they mainly occur as glycosides. We chose three derivatives, quercetin, luteolin, and rutin, in attempts to explore their redox chemistry in contrasting hydrogen peroxide environments. Initial addition of hydrogen peroxide in high concentration or gradual development constituted a main factor affecting their redox chemical properties, especially in case of quercetin. Our study exemplifies that a combination of a chemical assay (deoxyribose degradation) with an electrochemical method (square-wave voltammetry) provides insightful data. The ambiguity of the tested flavonoids to act either as anti- or pro-oxidant may complicate categorization, but probably contributed to their evolution as components of a successful metabolic system that benefits both producer and consumer."],["dc.description.sponsorship","Austrian Science Fund (FWF) [P24630-B21]"],["dc.identifier.doi","10.3390/ijms140611830"],["dc.identifier.isi","000320772500063"],["dc.identifier.pmid","23736691"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9484"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/29698"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Mdpi Ag"],["dc.relation.issn","1422-0067"],["dc.rights","CC BY 3.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/3.0"],["dc.title","Versatile Redox Chemistry Complicates Antioxidant Capacity Assessment: Flavonoids as Milieu-Dependent Anti- and Pro-Oxidants"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3917"],["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","International Journal of Molecular Sciences"],["dc.bibliographiccitation.volume","19"],["dc.contributor.affiliation","Chobot, Vladimir; \t\t \r\n\t\t Division of Molecular Systems Biology, Department of Ecogenomics and Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria, vladimir.chobot@univie.ac.at"],["dc.contributor.affiliation","Hadacek, Franz; \t\t \r\n\t\t Department of Plant Biochemistry, Albrecht-von-Haller Institut, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany, franz.hadacek@biologie.uni-goettingen.de"],["dc.contributor.affiliation","Bachmann, Gert; \t\t \r\n\t\t Division of Molecular Systems Biology, Department of Ecogenomics and Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria, gert.bachmann@univie.ac.at"],["dc.contributor.affiliation","Weckwerth, Wolfram; \t\t \r\n\t\t Division of Molecular Systems Biology, Department of Ecogenomics and Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria, wolfram.weckwerth@univie.ac.at"],["dc.contributor.affiliation","Kubicova, Lenka; \t\t \r\n\t\t Division of Molecular Systems Biology, Department of Ecogenomics and Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria, lenka.kubicova@univie.ac.at"],["dc.contributor.author","Chobot, Vladimir"],["dc.contributor.author","Hadacek, Franz"],["dc.contributor.author","Bachmann, Gert"],["dc.contributor.author","Weckwerth, Wolfram"],["dc.contributor.author","Kubicova, Lenka"],["dc.date.accessioned","2020-12-10T18:47:08Z"],["dc.date.available","2020-12-10T18:47:08Z"],["dc.date.issued","2018"],["dc.date.updated","2022-09-05T08:11:57Z"],["dc.description.sponsorship","Austrian Science Fund"],["dc.identifier.doi","10.3390/ijms19123917"],["dc.identifier.eissn","1422-0067"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/78657"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.relation.eissn","1422-0067"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0/"],["dc.title","Antioxidant Properties and the Formation of Iron Coordination Complexes of 8-Hydroxyquinoline"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","5850"],["dc.bibliographiccitation.issue","24"],["dc.bibliographiccitation.journal","Molecules"],["dc.bibliographiccitation.volume","25"],["dc.contributor.author","Chobot, Vladimir"],["dc.contributor.author","Hadacek, Franz"],["dc.contributor.author","Bachmann, Gert"],["dc.contributor.author","Weckwerth, Wolfram"],["dc.contributor.author","Kubicova, Lenka"],["dc.date.accessioned","2021-04-14T08:27:20Z"],["dc.date.available","2021-04-14T08:27:20Z"],["dc.date.issued","2020"],["dc.description.sponsorship","Austrian Science Fund"],["dc.identifier.doi","10.3390/molecules25245850"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/82251"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-399"],["dc.publisher","MDPI"],["dc.relation.eissn","1420-3049"],["dc.rights","https://creativecommons.org/licenses/by/4.0/"],["dc.title","In Vitro Evaluation of Pro- and Antioxidant Effects of Flavonoid Tricetin in Comparison to Myricetin"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","111"],["dc.bibliographiccitation.journal","Journal of Organometallic Chemistry"],["dc.bibliographiccitation.lastpage","115"],["dc.bibliographiccitation.volume","782"],["dc.contributor.author","Kubicova, Lenka"],["dc.contributor.author","Hadacek, Franz"],["dc.contributor.author","Weckwerth, Wolfram"],["dc.contributor.author","Chobot, Vladimir"],["dc.date.accessioned","2018-11-07T09:58:31Z"],["dc.date.available","2018-11-07T09:58:31Z"],["dc.date.issued","2015"],["dc.description.abstract","The tryptophan metabolite, quinolinic (2,3-pyridinedicarboxylic) acid, is known as an endogenous neurotoxin. Quinolinic acid can form coordination complexes with iron or copper. The effects of quinolinic acid on reactive oxygen species production in the presence of iron or copper were explored by a combination of chemical assays, classical site-specific and ascorbic acid-free variants of the deoxyribose degradation assay, and mass spectrometry (ESI-MS). Quinolinic acid showed evident antioxidant activity in chemical assays, but the effect was more pronounced in the presence of copper as transition metal catalyst than in presence of iron. Nano-ESI-MS confirmed the ability of quinolinic acid to form coordination complexes with iron(II) or copper(II) and quinolinic acid stability against oxidative attack by hydroxyl radicals. The results illustrate a highly milieu-dependent quinolinic acid chemistry when it enters reactions as competitive ligand. (C) 2015 The Authors. Published by Elsevier B.V."],["dc.description.sponsorship","Austrian Science Fund (FWF) [P24630-B21]"],["dc.identifier.doi","10.1016/j.jorganchem.2015.01.030"],["dc.identifier.isi","000351637900017"],["dc.identifier.pmid","25892824"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/13843"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/37376"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Sa"],["dc.publisher.place","Lausanne"],["dc.relation.conference","7th International Symposium on Bioorganometallic Chemistry"],["dc.relation.eventlocation","Vienna, AUSTRIA"],["dc.relation.issn","1872-8561"],["dc.relation.issn","0022-328X"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.title","Effects of endogenous neurotoxin quinolinic acid on reactive oxygen species production by Fenton reaction catalyzed by iron or copper"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","1986"],["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","International Journal of Molecular Sciences"],["dc.bibliographiccitation.volume","17"],["dc.contributor.author","Chobot, Vladimir"],["dc.contributor.author","Hadacek, Franz"],["dc.contributor.author","Bachmann, Gert"],["dc.contributor.author","Weckwerth, Wolfram"],["dc.contributor.author","Kubicova, Lenka"],["dc.date.accessioned","2018-11-07T10:04:51Z"],["dc.date.available","2018-11-07T10:04:51Z"],["dc.date.issued","2016"],["dc.description.abstract","The flavanol (+/-)-catechin shows an OH group but no 4-keto group on ring C (C3), and no conjugation between ring A and B. The related flavanone (+)-eriodictyol has a keto group on C4 but no 3-OH group on ring C. (+)-Taxifolin, another flavanone, has an OH on C3 and a keto group on C4 of the C ring. Deoxyribose degradation assay systems, with hydrogen peroxide and ascorbic acid either added or omitted, were performed in variants in which Fe(III) was added in a complex with ethylenediaminetetraacetic acid (EDTA). In combination with differential pulse voltammetry (DVP), the specific redox-chemical contributions of the ring A m-dihydroxyl groups could be explored more specifically in addition to those of the traditionally investigated o-dihydroxyl groups of ring B."],["dc.description.sponsorship","Austrian Science Fund (FWF) [P24630-B21]"],["dc.identifier.doi","10.3390/ijms17121986"],["dc.identifier.isi","000392280500030"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/14313"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/38785"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Mdpi Ag"],["dc.relation.issn","1422-0067"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.title","Pro- and Antioxidant Activity of Three Selected Flavan Type Flavonoids: Catechin, Eriodictyol and Taxifolin"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","20023"],["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","Molecules"],["dc.bibliographiccitation.lastpage","20033"],["dc.bibliographiccitation.volume","19"],["dc.contributor.author","Chobot, Vladimir"],["dc.contributor.author","Hadacek, Franz"],["dc.contributor.author","Kubicova, Lenka"],["dc.date.accessioned","2018-11-07T09:31:50Z"],["dc.date.available","2018-11-07T09:31:50Z"],["dc.date.issued","2014"],["dc.description.abstract","Iron is an essential co-factor for many enzymes that catalyze electron transfer reactions. It is well known that so-called \"poorly liganded\" iron can increase ROS concentrations and trigger oxidative stress that is capable of initiating apoptosis. Conversely, controlled ROS production has been recognized as an integral part of cellular signaling. Elevated ROS concentrations are associated with aging, inflammatory and degenerative diseases. Anti-aging properties have been attributed especially to antioxidant phenolic plant metabolites that represent food additives in our diet. Consequently, this study explores the effects of flavonoids (quercetin and rutin), several phenolic acids (caffeic, chlorogenic, and protocatechuic acid), and the alkaloid caffeine on iron(II) autoxidation and ROS production in comparison to the standard antioxidants ascorbic acid and Trolox. The iron(II) autoxidation assay was carried out in pH 6.0 (plant apoplast and inflamed human tissue) and 7.4 (cell cytoplasm and human blood plasma). The obtained results accentuate phenolic acids as the more specific antioxidants compared to ascorbic acid and Trolox. Flavonoid redox chemistry depends more on the chemical milieu, specifically on pH. In vivo, the presence of iron cannot be ruled out and \"wrongly\" or \"poorly\" complexed iron has been pointed out as causative agent of various age-related diseases."],["dc.description.sponsorship","Austrian Science Fund (FWF) [P24630-B21]"],["dc.identifier.doi","10.3390/molecules191220023"],["dc.identifier.isi","000346793200042"],["dc.identifier.pmid","25470272"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/11713"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/31621"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Mdpi Ag"],["dc.relation.issn","1420-3049"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.title","Effects of Selected Dietary Secondary Metabolites on Reactive Oxygen Species Production Caused by Iron(II) Autoxidation"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","21328"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","International Journal of Molecular Sciences"],["dc.bibliographiccitation.lastpage","21338"],["dc.bibliographiccitation.volume","14"],["dc.contributor.author","Kubicova, Lenka"],["dc.contributor.author","Hadacek, Franz"],["dc.contributor.author","Chobot, Vladimir"],["dc.date.accessioned","2018-11-07T09:17:50Z"],["dc.date.available","2018-11-07T09:17:50Z"],["dc.date.issued","2013"],["dc.description.abstract","Quinolinic acid (2,3-pyridinedicarboxylic acid, QUIN) is a well-known neurotoxin. Consequently, QUIN could produce reactive oxygen species (ROS). ROS are generated in reactions catalyzed by transition metals, especially iron (Fe). QUIN can form coordination complexes with iron. A combination of differential pulse voltammetry, deoxyribose degradation and Fe(II) autoxidation assays was used for explorating ROS formation in redox reactions that are catalyzed by iron in QUIN-Fe complexes. Differential pulse voltammetry showed an anodic shift of the iron redox potential if iron was liganded by QUIN. In the H2O2/FeCl3/ascorbic acid variant of the deoxyribose degradation assay, the dose-response curve was U-shaped. In the FeCl3/ascorbic acid variant, QUIN unambiguously showed antioxidant effects. In the Fe(II) autoxidation assay, QUIN decreased the rate of ROS production caused by Fe(II) oxidation. Our study confirms that QUIN toxicity may be caused by ROS generation via the Fenton reaction. This, however, applies only for unnaturally high concentrations that were used in attempts to provide support for the neurotoxic effect. In lower concentrations, we show that by liganding iron, QUIN affects the Fe(II)/Fe(III) ratios that are beneficial to homeostasis. Our results support the notion that redox chemistry can contribute to explaining the hormetic dose-response effects."],["dc.description.sponsorship","Austrian Science Fund (FWF) [P24630-B21]"],["dc.identifier.doi","10.3390/ijms141121328"],["dc.identifier.isi","000328624400009"],["dc.identifier.pmid","24232578"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9483"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/28264"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Mdpi Ag"],["dc.relation.issn","1422-0067"],["dc.rights","CC BY 3.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/3.0"],["dc.title","Quinolinic Acid: Neurotoxin or Oxidative Stress Modulator?"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]