title: Determination of free diferulic, disinapic and dicoumaric acids in plants and foods.
abstract: Hydroxycinnamates are common phenolic compounds of plants and plant foods, often found in substantial quantities. Due to their high in vitro antioxidant activity they can easily be oxidized under oxidative conditions. In this study, we found that in vitro oxidation of coumaric, ferulic and sinapic acids resulted mainly in dimeric compounds. We hypothesized that these dimers are present in plants and plant foods not only in their bound form but also as free acids that can be extracted from non-hydrolyzed samples. By applying sensitive UHPLC-MS/MS method, we were able to identify and quantify four free hydroxycinnamic acid dimers for the first time, namely 8-8'-disinapic, 8-5'-diferulic, 8-O-4'-diferulic and 8-3'-dicoumaric acids, in wheat sprouts, Chinese cabbage, millet sprouts, light beer and parsley. Concentrations of dicinnamates in plant tissues ranged from 0.05 to 2.8 μg g(-1) DW and the monomer:dimer ratio ranged from 2 to 850.
authors.affiliation: Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacky University, Šlechtitelů 11, 783 71 Olomouc, Czech Republic; Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University and Institute of Experimental Botany, Academy of Sciences of Czech Republic, Šlechtitelů 11, 783 71 Olomouc-Holice, Czech Republic. Electronic address: jiri.gruz@upol.cz.
authors.forename: Jiří
authors.initials: J
authors.lastname: Grúz
authors.affiliation: Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacky University, Šlechtitelů 11, 783 71 Olomouc, Czech Republic; Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University and Institute of Experimental Botany, Academy of Sciences of Czech Republic, Šlechtitelů 11, 783 71 Olomouc-Holice, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Pospíšil
authors.affiliation: Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University and Institute of Experimental Botany, Academy of Sciences of Czech Republic, Šlechtitelů 11, 783 71 Olomouc-Holice, Czech Republic.
authors.forename: Hana
authors.initials: H
authors.lastname: Kozubíková
authors.affiliation: Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University and Institute of Experimental Botany, Academy of Sciences of Czech Republic, Šlechtitelů 11, 783 71 Olomouc-Holice, Czech Republic.
authors.forename: Tomáš
authors.initials: T
authors.lastname: Pospíšil
authors.affiliation: Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacky University, Šlechtitelů 11, 783 71 Olomouc, Czech Republic; Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University and Institute of Experimental Botany, Academy of Sciences of Czech Republic, Šlechtitelů 11, 783 71 Olomouc-Holice, Czech Republic.
authors.forename: Karel
authors.initials: K
authors.lastname: Doležal
authors.affiliation: Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT), Adenauerring 20A, 76131 Karlsruhe, Germany.
authors.forename: Mirko
authors.initials: M
authors.lastname: Bunzel
authors.affiliation: Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacky University, Šlechtitelů 11, 783 71 Olomouc, Czech Republic; Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University and Institute of Experimental Botany, Academy of Sciences of Czech Republic, Šlechtitelů 11, 783 71 Olomouc-Holice, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Strnad
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D002853:Chromatography, Liquid; D002934:Cinnamates / Q000737:chemistry; D003373:Coumaric Acids / Q000737:chemistry*; D005502:Food; D009682:Magnetic Resonance Spectroscopy; D000066928:Millets / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry*; D010636:Phenols; D010666:Phenylpropionates / Q000737:chemistry; D053719:Tandem Mass Spectrometry; D014908:Triticum / Q000737:chemistry
chemical_list: D000975:Antioxidants; D002934:Cinnamates; D003373:Coumaric Acids; D010636:Phenols; D010666:Phenylpropionates; C516502:diferulic acid; C029010:cinnamic acid; C035253:3-phenylpropionic acid; C073734:sinapinic acid; D010100:Oxygen
keywords: Food; Hydroxycinnamic and dicinnamic acids; Liquid chromatography; Mass spectrometry; Oxidative coupling; Phenylpropanoids; Plant