title: Flavonol 3-O-glycosides series of Vitis vinifera Cv. Petit Verdot red wine grapes.
abstract: Petit Verdot grape skins by solid-phase extraction using a combination of reverse-phase and ion-exchanging materials. This procedure allowed us to separate a fraction of anthocyanin-free flavonol 3-O-glycosides that was further split into neutral and acidic subfractions, thus facilitating flavonol identification. By means of semipreparative reverse-phase high-performance liquid chromatography, we isolated several of these flavonol 3-O-glycosides for structural elucidation. The identification of different flavonol 3-O-glycosides was based on liquid chromatography-diode array detection-electrospray ionization-tandem mass spectrometry and NMR data when available. The results suggest that red grape flavonol 3-O-glycosides comprise three different complete series, according to the nature of the sugar moiety linked to the C-3 position. The 3-O-glucosides were the main derivative of the six possible flavonol aglycones (kaempferol, quercetin, isorhamnetin, myricetin, laricitrin, and syringetin), whereas the 3-O-galactoside derivatives were found as minor compounds for all of the flavonol aglycones. The 3-O-glucuronides are the third kind of red grape flavonol derivatives and normally account as minor compounds for all of the flavonol aglycones, with the exception of quercetin 3-O-glucuronide, which was as abundant as quercetin 3-O-glucoside. In addition, the presence of quercetin 3-O-(6"-rhamnosyl)-glucoside (rutin) was also detected as a trace compound in the skins of Petit Verdot grapes.
authors.affiliation: Instituto Regional de Investigación Científica Aplicada, Escuela Universitaria de Ingeniería Técnica Agrícola, Universidad de Castilla-La Mancha, Ciudad Real, Spain.
authors.forename: Noelia
authors.initials: N
authors.lastname: Castillo-Muñoz
authors.forename: Sergio
authors.initials: S
authors.lastname: Gómez-Alonso
authors.forename: Esteban
authors.initials: E
authors.lastname: García-Romero
authors.forename: M Victoria
authors.initials: MV
authors.lastname: Gómez
authors.forename: Aldrik H
authors.initials: AH
authors.lastname: Velders
authors.forename: Isidro
authors.initials: I
authors.lastname: Hermosín-Gutiérrez
mesh_terms: D002851:Chromatography, High Pressure Liquid; D044948:Flavonols / Q000032:analysis*; D005638:Fruit / Q000737:chemistry*; D006027:Glycosides / Q000032:analysis*; D011794:Quercetin / Q000032:analysis; D012431:Rutin / Q000032:analysis; D027843:Vitis / Q000737:chemistry*; D014920:Wine / Q000032:analysis
chemical_list: D044948:Flavonols; D006027:Glycosides; D012431:Rutin; D011794:Quercetin