title: Kale extract increases glutathione levels in V79 cells, but does not protect them against acute toxicity induced by hydrogen peroxide.
abstract: This study aims to evaluate the antioxidant potential of extracts of Brassica oleracea L. var. acephala DC. (kale) and several materials of Pieris brassicae L., a common pest of Brassica cultures using a cellular model with hamster lung fibroblast (V79 cells) under quiescent conditions and subjected to H₂O₂ induced oxidative stress. Cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and glutathione was determined by the 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB)-oxidized glutathione (GSSG) reductase recycling assay. The phenolic composition of the extracts was also established by HPLC-DAD. They presented acylated and non acylated flavonoid glycosides, some of them sulfated, and hydroxycinnamic acyl gentiobiosides. All extracts were cytotoxic by themselves at high concentrations and failed to protect V79 cells against H₂O₂ acute toxicity. No relationship between phenolic composition and cytotoxicity of the extracts was found. Rather, a significant increase in glutathione was observed in cells exposed to kale extract, which contained the highest amount and variety of flavonoids. It can be concluded that although flavonoids-rich extracts have the ability to increase cellular antioxidant defenses, the use of extracts of kale and P. brassicae materials by pharmaceutical or food industries, may constitute an insult to health, especially to debilitated individuals, if high doses are consumed.
authors.affiliation: REQUIMTE/Laboratório de Farmacognosia, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, Nº 228, 4050-313 Porto, Portugal.
authors.forename: Fátima
authors.initials: F
authors.lastname: Fernandes
authors.forename: Carla
authors.initials: C
authors.lastname: Sousa
authors.forename: Federico
authors.initials: F
authors.lastname: Ferreres
authors.forename: Patrícia
authors.initials: P
authors.lastname: Valentão
authors.forename: Fernando
authors.initials: F
authors.lastname: Remião
authors.forename: José A
authors.initials: JA
authors.lastname: Pereira
authors.forename: Paula B
authors.initials: PB
authors.lastname: Andrade
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001937:Brassica / Q000737:chemistry*; D002080:Butterflies / Q000737:chemistry*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D045424:Complex Mixtures / Q000737:chemistry; D006224:Cricetinae; D005243:Feces / Q000737:chemistry; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects*; D005419:Flavonoids / Q000494:pharmacology; D005978:Glutathione / Q000096:biosynthesis*; D006027:Glycosides / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007814:Larva / Q000737:chemistry; D018384:Oxidative Stress / Q000187:drug effects; D010636:Phenols / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry*; D013778:Tetrazolium Salts; D013844:Thiazoles
chemical_list: D000975:Antioxidants; D045424:Complex Mixtures; D005419:Flavonoids; D006027:Glycosides; D010636:Phenols; D010936:Plant Extracts; D013778:Tetrazolium Salts; D013844:Thiazoles; D006861:Hydrogen Peroxide; C022616:thiazolyl blue; D005978:Glutathione