Structural identification of theaflavin trigallate and tetragallate from black tea using liquid chromatography/electrospray ionization tandem mass spectrometry

Black tea contains two major pigments, theaflavins and thearubigins. These polyphenols have been associated with certain health benefits including prevention of heart disease and cancer. Elucidating and characterizing the structural aspects of thearubigins, the most abundant pigment in black tea, has been a challenge for many years. Therefore further studies of black tea polyphenols must be conducted in effort to solve this thearubigin dispute. In the present study, black tea extract was found to possess theaflavin trigallate and tetragallate by means of liquid chromatography/electrospray ionization mass spectrometry. These structures were confirmed by analysis of the MSn (n = 1-4) spectra and comparison of the MS/MS spectra of the product ions to the MS/MS spectra of authentic (-)-epigallocatechin-3-gallate, (-)-epicatechin-3- gallate and theaflavin-3,3′-digallate. To our knowledge, this is the first report to confirm the presence of theaflavin trigallate and tetragallate in black tea. © 2012 American Chemical Society.