title: A new class of blue anthocyanin-derived pigments isolated from red wines.
abstract: Two newly formed anthocyanin-derived pigments that revealed unique spectroscopic features, showing maximum absorption in their UV-vis spectra at 575 nm, were isolated by TSK Toyopearl HW-40 (S) gel column chromatography and semipreparative HPLC from an aged Port red wine. Further characterization by ESI/MS and NMR ((1)H, gCOSY) showed them to belong to a new class of pigments described here for the first time, the structure of which consisted of a pyranoanthocyanin moiety linked to a flavanol by a vinyl bridge. The extended conjugation of the pi electrons throughout all the pigment molecule is likely to confer a higher stability on it and is probably the origin of the intense blue color. The formation of these pigments was found to arise from the reaction between anthocyanin-pyruvic acid adducts and vinyl-flavanol adducts.
authors.affiliation: Centro de Investigação em Química, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal. nbmateus@fc.up.pt
authors.forename: Nuno
authors.initials: N
authors.lastname: Mateus
authors.forename: Artur M S
authors.initials: AM
authors.lastname: Silva
authors.forename: Julian C
authors.initials: JC
authors.lastname: Rivas-Gonzalo
authors.forename: Celestino
authors.initials: C
authors.lastname: Santos-Buelga
authors.forename: Victor
authors.initials: V
authors.lastname: de Freitas
mesh_terms: D000872:Anthocyanins / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D003116:Color; D005419:Flavonoids / Q000032:analysis; D044948:Flavonols; D009682:Magnetic Resonance Spectroscopy; D010860:Pigments, Biological / Q000032:analysis* / Q000737:chemistry; D019289:Pyruvic Acid / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013053:Spectrophotometry; D014753:Vinyl Compounds / Q000737:chemistry; D014920:Wine / Q000032:analysis*
chemical_list: D000872:Anthocyanins; D005419:Flavonoids; D044948:Flavonols; D010860:Pigments, Biological; D014753:Vinyl Compounds; D019289:Pyruvic Acid