Profiling and characterization by LC-MSn of the galloylquinic acids of green tea, tara tannin, and tannic acid.
Green tea, tara tannin, and tannic acid have been profiled for their contents of galloylquinic acids using LC-MS8. These procedures have provided evidence for the first observation of (i) 1-galloylquinic acid (11), 1,3,5-trigalloylquinic acid (22), 4-(digalloyl)quinic acid (28), 5-(digalloyl)quinic acid (29), and either 3-galloyl-5-(digalloyl)quinic acid (32) or 3-(digalloyl)-5-galloylquinic acid (33) from any source; (ii) 4-galloyl-5-(digalloyl)quinic acid (34), 5-galloyl-4-(digalloyl)quinic acid (35), 3-(digalloyl)-4,5-digalloylquinic acid (41), 4-(digalloyl)-3,5-digalloylquinic acid (40), 5-(digalloyl)-3,4-digalloylquinic acid (39), and 1,3,4-trigalloylquinic acid (21) from tara tannin; and (iii) 3-galloylquinic acid (12) and 4-galloylquinic acid (14) from green tea. The first mass spectrometric fragmentation data are reported for galloylquinic acids containing between five and eight gallic acid residues. For each of these mass ranges at least two isomers based on the 1,3,4,5-tetragalloylquinic acid core (25) and at least three based on the 3,4,5-trigalloylquinic acid core (24) were observed. Methanolysis of tara tannin yielded methyl gallate, methyl digallate, and methyl trigallate, demonstrating that some of these galloylquinic acids contained at least one side chain of up to four galloyl residues.
Clifford
Michael N
MN
School of Biomedical and Molecular Sciences, Centre for Nutrition and Food Safety, University of Surrey, Guildford, Surrey, United Kingdom. m.clifford@surrey.ac.uk
Stoupi
Stavroula
S
Kuhnert
Nikolai
N
D002853:Chromatography, Liquid; D053630:Depsides / Q000032:analysis; D005707:Gallic Acid / Q000032:analysis*; D013058:Mass Spectrometry; D053149:Plant Gums; D011134:Polysaccharides; D011801:Quinic Acid / Q000032:analysis*; D013634:Tannins / Q000737:chemistry*; D013662:Tea / Q000737:chemistry*
D053630:Depsides; D053149:Plant Gums; D011134:Polysaccharides; D013634:Tannins; D013662:Tea; D011801:Quinic Acid; C038612:tara gum; D005707:Gallic Acid