title: Antimutagenicity of green tea polyphenols in the liver of transgenic medaka.
abstract: We examined the ability of a mixture of the predominant green tea polyphenolic compounds (GTP) to reduce benzo[a]pyrene (B[a]P)-induced mutations in the cII gene of the lambda transgenic medaka. Fish were treated with 50 ppb B[a]P for 24 hr, followed by exposure to 2 ppm or 10 ppm GTP for 28 days. cII mutations in livers of fish exposed to B[a]P were increased significantly, 2.6-fold above controls. In contrast, the addition of GTP significantly reduced the frequency of cII mutants by 84%, comparable to that of controls. The frequencies of mutations at G:C basepairs, mutations that are highly characteristic of B[a]P exposure, were elevated significantly in treated fish. By comparison, B[a]P-exposed fish also treated with GTP showed reductions in these mutations, demonstrating a protective effect of GTP against B[a]P-induced mutagenesis. The antioxidant mechanism of GTP possibly played an important role in the reduction of B[a]P mutagenicity. These results corroborate findings from rodent models, showing that the protective effects of green tea extend to different species, and suggesting that similar mechanisms of B[a]P mutagenesis and GTP antimutagenesis are shared among the models. These studies illustrate the utility of lambda transgenic medaka for in vivo mutation analyses and suggest that this fish may be a valuable model in chemoprevention studies.
authors.affiliation: Aquatic Biotechnology and Environmental Laboratory, Warnell School of Forest Resources, University of Georgia, Athens, 30602, USA. rwinn@uga.edu
authors.forename: Richard N
authors.initials: RN
authors.lastname: Winn
authors.forename: Heather
authors.initials: H
authors.lastname: Kling
authors.forename: Michelle B
authors.initials: MB
authors.lastname: Norris
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D016587:Antimutagenic Agents / Q000737:chemistry / Q000494:pharmacology*; D001564:Benzo(a)pyrene / Q000037:antagonists & inhibitors / Q000633:toxicity; D002273:Carcinogens / Q000037:antagonists & inhibitors / Q000633:toxicity; D005419:Flavonoids / Q000737:chemistry / Q000494:pharmacology*; D008099:Liver / Q000737:chemistry / Q000187:drug effects*; D009152:Mutagenicity Tests; D009154:Mutation; D009990:Oryzias / Q000235:genetics; D010636:Phenols / Q000737:chemistry / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D059808:Polyphenols; D013662:Tea / Q000737:chemistry*
chemical_list: D016587:Antimutagenic Agents; D002273:Carcinogens; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols; D013662:Tea; D001564:Benzo(a)pyrene