Antioxidant properties of prepared blueberry (Vaccinium myrtillus) extracts.
A blueberry extract (A) and two anthocyanin-derived extracts (B and C) were prepared. The contents of polyphenols, flavonoids, anthocyanins, and anthocyanin-derived pigments of the extracts were determined for the first time. The pigment profile of blueberry extract A corresponded to 15 anthocyanins, whereas extract B was mainly composed of anthocyanin-pyruvic acid adducts of the blueberry original anthocyanins and extract C was mainly composed of the respective vinylpyranoanthocyanin-catechins (portisins). The extracts' abilities to inhibit lipid peroxidation, induced by 2,2'-azobis(2-methyl-propanimidamide) dihydrochloride in a liposomal membrane system were examined. The antioxidant capacities of the extracts were evaluated through monitoring oxygen consumption and by measuring the formation of conjugated dienes. All of the extracts provided protection of membranes against peroxyl radicals by increasing the induction time of oxidation. This effect increased with the polyphenol content and with the structural complexity of the anthocyanin-derived pigments of the extracts. The pigments present in extract C seemed to induce a higher protection of the liposome membranes toward oxidation. In addition, the antiradical properties and the reducing power of the extracts were determined by using DPPH and FRAP methods, respectively. The results from these assays were in agreement with those obtained with the liposome membranes.
Faria
Ana
A
Centro de Investigação em Química, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
Oliveira
Joana
J
Neves
Patrícia
P
Gameiro
Paula
P
Santos-Buelga
Celestino
C
de Freitas
Victor
V
Mateus
Nuno
N
D000872:Anthocyanins / Q000032:analysis; D000975:Antioxidants / Q000032:analysis* / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D005419:Flavonoids / Q000032:analysis; D016166:Free Radical Scavengers / Q000032:analysis; D005638:Fruit / Q000737:chemistry*; D015227:Lipid Peroxidation / Q000187:drug effects; D010101:Oxygen Consumption; D010636:Phenols / Q000032:analysis; D010936:Plant Extracts / Q000737:chemistry*; D059808:Polyphenols; D029796:Vaccinium / Q000737:chemistry*
D000872:Anthocyanins; D000975:Antioxidants; D005419:Flavonoids; D016166:Free Radical Scavengers; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols