title: Structural annotation and elucidation of conjugated phenolic compounds in black, green, and white tea extracts.
abstract: Advanced analytical approaches consisting of both LC-LTQ-Orbitrap Fourier transformed (FT)-MS and LC-time-of-flight-(TOF)-MS coupled to solid-phase extraction (SPE) NMR were used to obtain more insight into the complex phenolic composition of tea. On the basis of the combined structural information from (i) accurate mass fragmentation spectra, derived by using LC-Orbitrap FTMS(n), and (ii) proton NMR spectra, derived after LC-TOFMS triggered SPE trapping of selected compounds, 177 phenolic compounds were annotated. Most of these phenolics were glycosylated and acetylated derivatives of flavan-3-ols and flavonols. Principal component analysis based on the relative abundance of the annotated phenolic compounds in 17 commercially available black, green, and white tea products separated the black teas from the green and white teas, with epicatechin-3,5-di-O-gallate and prodelphinidin-O-gallate being among the main discriminators. The results indicate that the combined use of LC-LTQ-Orbitrap FTMS and LC-TOFMS-SPE-NMR leads to a more comprehensive metabolite description and comparison of tea and other plant samples.
authors.affiliation: Laboratory of Biochemistry, Wageningen University and Research Centre , Dreijenlaan 3, 6703 HA Wageningen, The Netherlands. justin.vanderhooft@wur.nl
authors.forename: Justin J J
authors.initials: JJ
authors.lastname: van der Hooft
authors.forename: Moktar
authors.initials: M
authors.lastname: Akermi
authors.forename: Fatma Yelda
authors.initials: FY
authors.lastname: Ünlü
authors.forename: Velitchka
authors.initials: V
authors.lastname: Mihaleva
authors.forename: Victoria Gomez
authors.initials: VG
authors.lastname: Roldan
authors.forename: Raoul J
authors.initials: RJ
authors.lastname: Bino
authors.forename: Ric C H
authors.initials: RC
authors.lastname: de Vos
authors.forename: Jacques
authors.initials: J
authors.lastname: Vervoort
mesh_terms: D028241:Camellia sinensis / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D015394:Molecular Structure; D010636:Phenols / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*; D013662:Tea / Q000737:chemistry*
chemical_list: D010636:Phenols; D010936:Plant Extracts; D013662:Tea