title: Seasonal variations of the phenolic constituents in bilberry (Vaccinium myrtillus L.) leaves, stems and fruits, and their antioxidant activity.
abstract: The seasonal variations of the content and diversity of phenolic compounds, as well as the antioxidant activity of leaves, stems and fruits of bilberry collected in May, July and September, were evaluated for two consecutive years. UPLC/MS(n) analyses showed the predominance of anthocyanins in fruits, caffeic acid derivatives in leaves whereas flavanol oligomers represented more than half of the phenolic compounds in stems. Thioacidolysis revealed degrees of polymerization between 2 and 4 and (-)-epicatechin as the main flavanol unit. The sum of the phenolic compounds by UPLC was highly correlated with the total polyphenol content and the antioxidant activity in the DPPH test for all the extracts except for May leaves. The latter were relatively rich in p-coumaric acid derivatives. Seasonal effects were more marked for leaves, which exhibited higher antioxidant activities and phenolic contents in July and September when these parameters were at their highest in July for stems.
authors.affiliation: "Gheorghe Asachi" Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 700050 Iasi, Romania; UMR408 Safety and Quality of Plant Products, INRA, University of Avignon, F-84000 Avignon, France.
authors.forename: Oana-Crina
authors.initials: OC
authors.lastname: Bujor
authors.affiliation: UMR408 Safety and Quality of Plant Products, INRA, University of Avignon, F-84000 Avignon, France.
authors.forename: Carine
authors.initials: C
authors.lastname: Le Bourvellec
authors.affiliation: "Gheorghe Asachi" Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 700050 Iasi, Romania.
authors.forename: Irina
authors.initials: I
authors.lastname: Volf
authors.affiliation: "Gheorghe Asachi" Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 700050 Iasi, Romania.
authors.forename: Valentin I
authors.initials: VI
authors.lastname: Popa
authors.affiliation: UMR408 Safety and Quality of Plant Products, INRA, University of Avignon, F-84000 Avignon, France. Electronic address: claire.dufour@avignon.inra.fr.
authors.forename: Claire
authors.initials: C
authors.lastname: Dufour
mesh_terms: D000872:Anthocyanins / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D003373:Coumaric Acids / Q000737:chemistry; D016166:Free Radical Scavengers / Q000737:chemistry; D005638:Fruit / Q000737:chemistry*; D013058:Mass Spectrometry; D010851:Picrates / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D018547:Plant Stems / Q000737:chemistry; D059808:Polyphenols / Q000737:chemistry*; D011422:Propionates; D012621:Seasons; D021241:Spectrometry, Mass, Electrospray Ionization; D029800:Vaccinium myrtillus / Q000737:chemistry*
chemical_list: D000872:Anthocyanins; D001713:Biphenyl Compounds; D003373:Coumaric Acids; D016166:Free Radical Scavengers; D010851:Picrates; D010936:Plant Extracts; D059808:Polyphenols; D011422:Propionates; C073305:Vaccinium myrtillus extract; C004931:1,1-diphenyl-2-picrylhydrazyl; C495469:p-coumaric acid
keywords: Antiradical capacity; DPPH; Folin–Ciocalteu; Polyphenols; Thioacidolysis; UPLC/MS(n); Vegetation periods