title: Influence of Laccase and Tyrosinase on the Antioxidant Capacity of Selected Phenolic Compounds on Human Cell Lines.
abstract: Polyphenolic compounds affect the color, odor and taste of numerous food products of plant origin. In addition to the visual and gustatory properties, they serve as radical scavengers and have antioxidant effects. Polyphenols, especially resveratrol in red wine, have gained increasing scientific and public interest due to their presumptive beneficial impact on human health. Enzymatic oxidation of phenolic compounds takes place under the influence of polyphenol oxidases (PPO), including tyrosinase and laccase. Several studies have demonstrated the radical scavenger effect of plants, food products and individual polyphenols in vitro, but, apart from resveratrol, such impact has not been proved in physiological test systems. Furthermore, only a few data exist on the antioxidant capacities of the enzymatic oxidation products of phenolic compounds generated by PPO. We report here first results about the antioxidant effects of phenolic substances, before and after oxidation by fungal model tyrosinase and laccase. In general, the common chemical 2,2-diphenyl-1-picrylhydrazyl assay and the biological tests using two different types of cell cultures (monocytes and endothelial cells) delivered similar results. The phenols tested showed significant differences with respect to their antioxidant activity in all test systems. Their antioxidant capacities after enzymatic conversion decreased or increased depending on the individual PPO used.
authors.affiliation: Institute for Molecular Biophysics, Johannes Gutenberg University of Mainz, Jakob-Welder-Weg, 26, 55128 Mainz, Germany. riebelm@uni-mainz.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Riebel
authors.affiliation: Institute for Microbiology and Wine Research, Johannes Gutenberg University of Mainz, Johann-Joachim-Becher-Weg, 15, 55128 Mainz, Germany. sabel@uni-mainz.de.
authors.forename: Andrea
authors.initials: A
authors.lastname: Sabel
authors.affiliation: Institute for Microbiology and Wine Research, Johannes Gutenberg University of Mainz, Johann-Joachim-Becher-Weg, 15, 55128 Mainz, Germany. hclaus@uni-mainz.de.
authors.forename: Harald
authors.initials: H
authors.lastname: Claus
authors.affiliation: Institute for Molecular Biophysics, Johannes Gutenberg University of Mainz, Jakob-Welder-Weg, 26, 55128 Mainz, Germany. petra.fronk@uni-mainz.de.
authors.forename: Petra
authors.initials: P
authors.lastname: Fronk
authors.affiliation: Department of Pharmacology, Johannes Gutenberg University Medical Center of Mainz, Obere Zahlbacher Str. 67, 55131 Mainz, Germany. xianing@uni-mainz.de.
authors.forename: Ning
authors.initials: N
authors.lastname: Xia
authors.affiliation: Department of Pharmacology, Johannes Gutenberg University Medical Center of Mainz, Obere Zahlbacher Str. 67, 55131 Mainz, Germany. huigeli@uni-mainz.de.
authors.forename: Huige
authors.initials: H
authors.lastname: Li
authors.affiliation: Institute for Microbiology and Wine Research, Johannes Gutenberg University of Mainz, Johann-Joachim-Becher-Weg, 15, 55128 Mainz, Germany. hkoenig@uni-mainz.de.
authors.forename: Helmut
authors.initials: H
authors.lastname: König
authors.affiliation: Institute for Molecular Biophysics, Johannes Gutenberg University of Mainz, Jakob-Welder-Weg, 26, 55128 Mainz, Germany. hdecker@uni-mainz.de.
authors.forename: Heinz
authors.initials: H
authors.lastname: Decker
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology*; D002460:Cell Line; D005656:Fungal Proteins / Q000378:metabolism; D006801:Humans; D042845:Laccase / Q000378:metabolism*; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D059808:Polyphenols / Q000032:analysis / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D005656:Fungal Proteins; D010936:Plant Extracts; D059808:Polyphenols; D042845:Laccase; D014442:Monophenol Monooxygenase
keywords: DPPH•; antioxidant activity; cell cultures; laccase; oxidation; polyphenols; tyrosinase