title: Effective Conversion of Metmyoglobin to Oxymyoglobin by Cysteine-Substituted Polyphenols.
abstract: Reaction products from the peroxidase-catalyzed oxidation of polyphenols in the presence of cysteine showed a potent activity for reducing metmyogolobin (MetMb) to bright-colored oxymyogolobin (MbO2). High-performance liquid chromatography (HPLC) purification of the reaction products from catechin, chlorogenic acid, dihydrocaffeic acid, hydroxytyrosol, nordihydroguaiaretic acid, and rosmarinic acid afforded corresponding S-cysteinyl compounds, the structures of which were determined by nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). The isolated cysteinyl polyphenols showed a concentration-dependent reducing activity for MetMb to MbO2 for the initial 1 h. However, after 1 h, some of them decreased the amount of MbO2 produced. The effect of the number of cysteinyl sulfur substitutions in polyphenols on both MetMb reduction and MbO2 maintenance was examined using hydroxytyrosols with different numbers of cysteine substitutions; these hydroxytyrosols were synthesized from hydroxytyrosol and an N-acetylcysteine methyl ester. The hydroxytyrosol derivative substituted with two N-acetylcysteine esters exhibited the most effective reducing activity without any effect on MbO2.
authors.affiliation: Graduate School of Human Life Science, Osaka City University , Osaka 558-8585, Japan.|Graduate School of Integrated Arts and Science, Tokushima University , Tokushima 770-8502, Japan.
authors.forename: Sari
authors.initials: S
authors.lastname: Honda
authors.affiliation: Graduate School of Integrated Arts and Science, Tokushima University , Tokushima 770-8502, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Miura
authors.affiliation: Graduate School of Human Life Science, Osaka City University , Osaka 558-8585, Japan.
authors.forename: Toshiya
authors.initials: T
authors.lastname: Masuda
authors.affiliation: Faculty of Human Life Science, Shikoku University , Tokushima 771-1192, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Masuda
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008786:Metmyoglobin / Q000737:chemistry*; D015394:Molecular Structure; D009211:Myoglobin / Q000737:chemistry*; D010084:Oxidation-Reduction; D059808:Polyphenols / Q000737:chemistry*
chemical_list: D009211:Myoglobin; D059808:Polyphenols; C017595:oxymyoglobin; D008786:Metmyoglobin; D003545:Cysteine
keywords: bright meat color preservation; cysteinyl polyphenols; metmyoglobin reducing activity; peroxidase-catalyzed oxidation