title: Isolation and structural characterization of new acylated anthocyanin-vinyl-flavanol pigments occurring in aging red wines.
abstract: Three newly formed pigments were detected and isolated from a 2-year-old Port wine through TSK Toyopearl HW-40(S) gel column chromatography and characterized by UV-visible spectrophotometry, NMR, and mass spectrometry (ESI/MS). (1)H NMR and (13)C NMR data for these pigments obtained using 1D and 2D NMR techniques (COSY, NOESY, gHSQC, and gHMBC) are reported for the first time. The structure of the pigments was found to correspond to the vinyl cycloadducts of malvidin 3-coumaroylglucoside bearing either a procyanidin dimer or a flavanol monomer ((+)-catechin or (-)-epicatechin). Additionally, conformational analysis was performed for one of these newly formed pigment using computer-assisted model building and molecular mechanics. A chemical nomenclature is proposed to unambiguously name this new family of anthocyanin-derived pigments.
authors.affiliation: Centro de Investigação em Química, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 687, Portugal. nbmateus@fc.up.pt
authors.forename: Nuno
authors.initials: N
authors.lastname: Mateus
authors.forename: Elisabete
authors.initials: E
authors.lastname: Carvalho
authors.forename: Alexandre R F
authors.initials: AR
authors.lastname: Carvalho
authors.forename: André
authors.initials: A
authors.lastname: Melo
authors.forename: Ana M
authors.initials: AM
authors.lastname: González-Paramás
authors.forename: Celestino
authors.initials: C
authors.lastname: Santos-Buelga
authors.forename: Artur M S
authors.initials: AM
authors.lastname: Silva
authors.forename: Victor
authors.initials: V
authors.lastname: De Freitas
mesh_terms: D000215:Acylation; D000872:Anthocyanins / Q000737:chemistry / Q000302:isolation & purification*; D003198:Computer Simulation; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D010860:Pigments, Biological / Q000737:chemistry / Q000302:isolation & purification*; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet; D009626:Terminology as Topic; D013997:Time Factors; D014920:Wine / Q000032:analysis*
chemical_list: C471172:8-vinyl-epi-(4-8)-cat-(1V,2V-5O,4)-malvidin-3-coumaroylglucoside; C471173:8-vinylcat-(1V,2V-5O,4)-malvidin-3-coumaroylglucoside; D000872:Anthocyanins; D010860:Pigments, Biological