title: Protective effects of black tea extract against oxidative DNA damage in human lymphocytes.
abstract: The aim of the present study was to examine the genoprotective and radioprotective effects of black tea extract (BTE) against the induction of single strand DNA breaks in human lymphocytes subjected to hydrogen peroxide (H2O2) or gamma-rays (2 Gy dose). Lymphocytes were incubated with or without different concentrations of BTE (0.005-500 µg/ml) for 30 min, followed by treatment with or without H2O2 (0.088 µmol/l) for 5 min. To examine the radioprotective effect of BTE, the lymphocytes were incubated with or without BTE for 30 and 60 min prior to and following in vitro irradiation. Oxidative damage to DNA was monitored using a comet assay. BTE at lower concentrations prevented H2O2-induced DNA damage. An increase in BTE concentrations resulted in increased formation of single strand DNA breaks. BTE also exerted significant protective effects against gamma radiation-induced total DNA damage in healthy lymphocytes during their 30 or 60 min incubation with BTE prior to or following irradiation. Therefore, the protective effect of BTE against irradiation was time-dependent. The results contribute to the research on potential beneficial effects of natural compounds, such as BTE, in cancer and its protective effects of normal tissue during radiation therapy.
authors.affiliation: Institute of Medical Chemistry, Biochemistry and Clinical Biochemistry, Faculty of Medicine, Comenius University, Bratislava 813 72, Slovakia.
authors.forename: Miriam
authors.initials: M
authors.lastname: Ježovičová
authors.affiliation: Institute of Medical Chemistry, Biochemistry and Clinical Biochemistry, Faculty of Medicine, Comenius University, Bratislava 813 72, Slovakia.
authors.forename: Katarína
authors.initials: K
authors.lastname: Koňariková
authors.affiliation: Institute of Medical Chemistry, Biochemistry and Clinical Biochemistry, Faculty of Medicine, Comenius University, Bratislava 813 72, Slovakia.
authors.forename: Zdeňka
authors.initials: Z
authors.lastname: Ďuračková
authors.affiliation: Molecule of Life, Ltd., Lichnerova, Senec 903 01, Slovakia.
authors.forename: Ján
authors.initials: J
authors.lastname: Keresteš
authors.affiliation: Radiotherapy Department of St. Elisabeth Cancer Institute, Bratislava 813 72, Slovakia.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Králik
authors.affiliation: Institute of Medical Chemistry, Biochemistry and Clinical Biochemistry, Faculty of Medicine, Comenius University, Bratislava 813 72, Slovakia.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Žitňanová
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000378:metabolism; D019610:Cytoprotection / Q000187:drug effects* / Q000528:radiation effects; D053904:DNA Breaks, Single-Stranded / Q000187:drug effects / Q000528:radiation effects; D004249:DNA Damage; D005720:Gamma Rays; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D008214:Lymphocytes / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D008875:Middle Aged; D010084:Oxidation-Reduction / Q000187:drug effects / Q000528:radiation effects; D010936:Plant Extracts / Q000494:pharmacology*; D020011:Protective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D013662:Tea / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D020011:Protective Agents; D013662:Tea; D006861:Hydrogen Peroxide