title: Fourteen-week toxicity study of green tea extract in rats and mice.
abstract: The toxicity of green tea extract (GTE) was evaluated in 14-week gavage studies in male and female F344/NTac rats and B6C3F1 mice at doses up to 1,000 mg/kg. In the rats, no treatment-related mortality was noted. In the mice, treatment-related mortality occurred in male and female mice in the 1,000 mg/kg dose groups. The cause of early deaths was likely related to liver necrosis. Treatment-related histopathological changes were seen in both species in the liver, nose, mesenteric lymph nodes, and thymus. In addition, in mice, changes were seen in the Peyer's patches, spleen, and mandibular lymph nodes. The no adverse effect level (NOAEL) for the liver in both species was 500 mg/kg. In the nose of rats, the NOAEL in males was 62.5 mg/kg, and in females no NOAEL was found. No NOAEL was found in the nose of female or male mice. The changes in the liver and nose were considered primary toxic effects of GTE, while the changes in other organs were considered to be secondary effects. The nose and liver are organs with high metabolic enzyme activity. The increased susceptibility of the nose and liver suggests a role for GTE metabolites in toxicity induction.
authors.affiliation: National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
authors.forename: Po C
authors.initials: PC
authors.lastname: Chan
authors.forename: Yuval
authors.initials: Y
authors.lastname: Ramot
authors.forename: David E
authors.initials: DE
authors.lastname: Malarkey
authors.forename: Pamela
authors.initials: P
authors.lastname: Blackshear
authors.forename: Grace E
authors.initials: GE
authors.lastname: Kissling
authors.forename: Greg
authors.initials: G
authors.lastname: Travlos
authors.forename: Abraham
authors.initials: A
authors.lastname: Nyska
mesh_terms: D000818:Animals; D028241:Camellia sinensis / Q000737:chemistry*; D056486:Chemical and Drug Induced Liver Injury / Q000209:etiology / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D005260:Female; D008099:Liver / Q000187:drug effects / Q000473:pathology; D008136:Longevity / Q000187:drug effects; D008221:Lymphoid Tissue / Q000187:drug effects / Q000473:pathology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D019055:No-Observed-Adverse-Effect Level; D009666:Nose / Q000187:drug effects / Q000473:pathology; D009929:Organ Size / Q000187:drug effects; D010936:Plant Extracts / Q000633:toxicity*; D051381:Rats; D011916:Rats, Inbred F344; D013662:Tea / Q000737:chemistry*; D018675:Toxicity Tests
chemical_list: D010936:Plant Extracts; D013662:Tea