title: Characterization by LC-MS(n) of four new classes of p-coumaric acid-containing diacyl chlorogenic acids in green coffee beans.
abstract: LC-MS4 has been used to detect and characterize in green coffee beans 15 quantitatively minor p-coumaric acid-containing chlorogenic acids not previously reported in nature. These comprise 3,4-di-p-coumaroylquinic acid, 3,5-di-p-coumaroylquinic acid, and 4,5-di-p-coumaroylquinic acid (Mr 484); 3-p-coumaroyl-4-caffeoylquinic acid, 3-p-coumaroyl-5-caffeoylquinic acid, 4-p-coumaroyl-5-caffeoylquinic acid, 3-caffeoyl-4-p-coumaroyl-quinic acid, 3-caffeoyl-5-p-coumaroyl-quinic acid; and 4-caffeoyl-5-p-coumaroyl-quinic acid (Mr 500); 3-p-coumaroyl-4-feruloylquinic acid, 3-p-coumaroyl-5-feruloylquinic acid and 4-p-coumaroyl-5-feruloylquinic acid (Mr 514); and 4-dimethoxycinnamoyl-5-p-coumaroylquinic acid and two isomers (Mr 528) for which identities could not be assigned unequivocally. Structures have been assigned on the basis of LC-MS4 patterns of fragmentation. Forty-five chlorogenic acids have now been characterized in green Robusta coffee beans.
authors.affiliation: Center for Nutrition and Food Safety, School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom. m.clifford@surrey.ac.uk
authors.forename: Michael N
authors.initials: MN
authors.lastname: Clifford
authors.forename: Serena
authors.initials: S
authors.lastname: Marks
authors.forename: Susan
authors.initials: S
authors.lastname: Knight
authors.forename: Nikolai
authors.initials: N
authors.lastname: Kuhnert
mesh_terms: D002726:Chlorogenic Acid / Q000737:chemistry*; D002853:Chromatography, Liquid / Q000379:methods*; D040503:Coffea / Q000737:chemistry*; D003373:Coumaric Acids / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D011422:Propionates; D011801:Quinic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D012639:Seeds / Q000737:chemistry*
chemical_list: D003373:Coumaric Acids; D011422:Propionates; C472707:caffeoylquinic acid; D011801:Quinic Acid; D002726:Chlorogenic Acid; C004999:ferulic acid; C495469:p-coumaric acid