title: Genotoxicity studies on green tea catechin.
abstract: The beneficial effects of tea catechins are well documented. We evaluated the genotoxic potential of a green tea catechin preparation using established genotoxicity assays, including a bacterial reverse mutation assay (Ames test), a chromosomal aberration assay in cultured Chinese hamster lung cells (CHL/IU), a mouse lymphoma L5178Y/tk assay, and a bone marrow micronucleus (MN) assay in ICR CD mice and SD rats. No significant increases in the number of revertant colonies were observed in the Ames test, but positive responses were observed in two in vitro assays: the chromosomal aberration assay and mouse lymphoma L5178/tk assay. However, the in vivo study demonstrated no significant increase in micronucleated polychromatic erythrocytes (MNPCE) in the bone marrow of both ICR CD mice and SD rats administered a high dose of the green tea catechin preparation up to 2000mg/kg. Combined with favorable epidemiological information suggesting a chemopreventive effect of tea catechins on carcinogenesis, we conclude that green tea catechin presents no significant genotoxic concern under the anticipated conditions of use. These results are consistent with other genotoxicity studies of tea catechins, which show minimal, if any, genotoxic potential.
authors.affiliation: Safety Science Research Laboratories, Kao Corporation, 2606 Akabane, Ichikai-Machi, Haga-Gun, Tochigi 321-3497, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Ogura
authors.forename: N
authors.initials: N
authors.lastname: Ikeda
authors.forename: K
authors.initials: K
authors.lastname: Yuki
authors.forename: O
authors.initials: O
authors.lastname: Morita
authors.forename: K
authors.initials: K
authors.lastname: Saigo
authors.forename: C
authors.initials: C
authors.lastname: Blackstock
authors.forename: N
authors.initials: N
authors.lastname: Nishiyama
authors.forename: T
authors.initials: T
authors.lastname: Kasamatsu
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects; D002392:Catechin / Q000633:toxicity*; D002460:Cell Line; D045744:Cell Line, Tumor; D002869:Chromosome Aberrations / Q000187:drug effects; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D051379:Mice; D008813:Mice, Inbred ICR; D015162:Micronucleus Tests; D009152:Mutagenicity Tests; D009153:Mutagens; D051381:Rats; D017207:Rats, Sprague-Dawley; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D013662:Tea / Q000737:chemistry*; D013937:Thymidine Kinase / Q000235:genetics
chemical_list: D009153:Mutagens; D013662:Tea; D002392:Catechin; D013937:Thymidine Kinase