title: Phenolic extracts of brewers' spent grain (BSG) as functional ingredients - assessment of their DNA protective effect against oxidant-induced DNA single strand breaks in U937 cells.
abstract: Brewers' spent grain (BSG), a by-product of the brewing industry, contains high amounts of phenolic acids, which have antioxidant effects. The present study examined the ability of BSG extracts to protect against the genotoxic effects of oxidants, hydrogen peroxide (H(2)O(2)), 3-morpholinosydnonimine hydrochloride (SIN-1), 4-nitroquinoline 1-oxide (4-NQO) and tert-butylhydroperoxide (t-BOOH) in U937 cells. Four pale (P1-P4) and four black (B1-B4) BSG extracts were investigated. U937 cells were pre-incubated with BSG extracts, exposed to the oxidants and the DNA damage was measured by the Comet assay. The black BSG extracts (B1-B4) significantly protected against H(2)O(2)-induced DNA damage. Extract B2, which had the highest phenol content, provided the greatest protection. Extracts P2, B2, B3 and B4 provided significant protection against SIN-1-induced DNA damage. None of the extracts protected against DNA damage induced by t-BOOH and 4-NQO. The DNA protective effects of the BSG phenolic extracts may be related to iron chelation.
authors.affiliation: School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
authors.forename: Aoife L
authors.initials: AL
authors.lastname: McCarthy
authors.forename: Yvonne C
authors.initials: YC
authors.lastname: O'Callaghan
authors.forename: Alan
authors.initials: A
authors.lastname: Connolly
authors.forename: Charles O
authors.initials: CO
authors.lastname: Piggott
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Fitzgerald
authors.forename: Nora M
authors.initials: NM
authors.lastname: O'Brien
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D053904:DNA Breaks, Single-Stranded / Q000187:drug effects*; D004249:DNA Damage / Q000187:drug effects*; D002523:Edible Grain / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity*; D007220:Industrial Waste / Q000032:analysis*; D016877:Oxidants / Q000633:toxicity*; D010636:Phenols / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology*; D020011:Protective Agents / Q000494:pharmacology*; D020298:U937 Cells
chemical_list: D000975:Antioxidants; D007220:Industrial Waste; D016877:Oxidants; D010636:Phenols; D010936:Plant Extracts; D020011:Protective Agents; D006861:Hydrogen Peroxide