title: Analysis of theaflavins and thearubigins from black tea extract by MALDI-TOF mass spectrometry.
abstract: Black tea contains two major groups of pigments, theaflavins (TFs) and thearubigins (TRs). TFs contain a bis-flavan substituted 1,2-dihydroxy-3,4-benzotropolone moiety. Unlike the TFs, TRs have not yet been characterized. The chemical structure of the TRs remains a mystery. The present paper reports our effort to study the structure of TFs and TRs using delayed pulsed ion extraction of ions generated via the matrix-assisted laser desorption ionization (MALDI) technique, on line with a Linear time-of-flight (TOF) mass spectrometer. Spectra of standard TFs show not only pseudomolecular ions but also ions resulting from fragmentation. The analysis of MALDI-TOF spectra of black tea fractions shows the structure of some TRs, which are similar to those of TFs because the same loss of mass is observed.
authors.affiliation: Department of Food Science and Center for Advanced Food Technology, Rutgers University, 65 Dudley Road, New Brunswick, New Jersey 08901-8520, USA.
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Menet
authors.forename: Shengmin
authors.initials: S
authors.lastname: Sang
authors.forename: Chung S
authors.initials: CS
authors.lastname: Yang
authors.forename: Chi-Tang
authors.initials: CT
authors.lastname: Ho
authors.forename: Robert T
authors.initials: RT
authors.lastname: Rosen
mesh_terms: D044946:Biflavonoids / Q000032:analysis* / Q000737:chemistry; D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000031:analogs & derivatives* / Q000032:analysis* / Q000737:chemistry; D005285:Fermentation; D015394:Molecular Structure; D010636:Phenols / Q000032:analysis* / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D059808:Polyphenols; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D044946:Biflavonoids; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols; C086701:thearubigin; C056068:theaflavin; D002392:Catechin