title: Dose-Dependent Protective and Inductive Effects of Xanthohumol on Oxidative DNA Damage inSaccharomyces cerevisiae.
abstract: The effect of xanthohumol, a prenylflavonoid isolated from the hop plant (Humulus lupulusL.), onSaccharomyces cerevisiaeDNA oxidative damage and viability was evaluated. Yeast cultures under oxidative stress, induced by H2O2, displayed stronger growth in the presence of 5 mg/L of xanthohumol than cultures with only H2O2. Likewise, DNA damage assessed by the comet assay was significantly lower in cells co-incubated with xanthohumol and H2O2. Accordingly, fluorescence of dichlorofluorescein in cells treated with H2O2and xanthohumol was considerably lower than in cells exclusively treated with H2O2, indicative of a reactive oxygen species scavenging mechanism and consequent formation of oxidation products, as detected by mass spectrometry. However, at concentrations above 5 mg/L, xanthohumol elicited an opposite effect, leading to a slower growth rate and significant increase in DNA damage. A yeastyap1deletion mutant strain sensitive to oxidative stress grew more slowly in the presence of at least 5 mg/L of xanthohumol than cultures of the wild type, suggesting that xanthohumol toxicity is mediated by oxidative stress. This evidence provides further insight into the impact of xanthohumol on yeast cells, supporting dose-dependent antioxidant/antigenotoxic and prooxidant/genotoxic effects.
authors.affiliation: REQUIMTE/LAQV - Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre 687, PT-4169-007 Porto, Portugal.
authors.forename: Daniel O
authors.initials: DO
authors.lastname: Carvalho
authors.affiliation: Center for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), Department of Biology, University of Minho, Campus de Gualtar, PT-4710-057 Braga, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Oliveira
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, PT-4710-057 Braga, Portugal.
authors.forename: Björn
authors.initials: B
authors.lastname: Johansson
authors.affiliation: REQUIMTE/LAQV - Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre 687, PT-4169-007 Porto, Portugal.
authors.forename: Luís F
authors.initials: LF
authors.lastname: Guido
keywords: Saccharomyces cerevisiae; antioxidant and prooxidant capacity; comet assay; genotoxic and antigenotoxic effects; xanthohumol; yeast viability