title: Protective effect of yellow tea extract on N-nitrosodiethylamine-induced liver carcinogenesis.
abstract: Context Yellow tea containing the same catechins as other types of tea but in different proportions has been suggested to possess potent anticancer activities. Objective This study investigates the chemopreventive effect of yellow tea aqueous extract against N-nitrosodiethylamine (NDEA)-induced liver carcinogenesis in rats by employing histological and biochemical methods. Materials and methods Wistar rats were divided randomly into four groups: control (I), yellow tea (II), NDEA (III), and yellow tea + NDEA (IV). Groups II and IV were exposed via a diet to yellow tea extract in a concentration of 10 g/kg feed; groups III and IV received 0.01% NDEA in drinking water. The experiment lasted for 13 weeks. Results Daily intake of yellow tea in an average dose of 800 mg/kg b.w. alleviated the carcinogenic effect of NDEA as evidenced by reversed histopathological changes towards normal hepatocellular architecture and decreased lipid peroxidation, protein carbonyl formation, and DNA degradation by 64%, 37% and 15%, respectively, as compared with values obtained in NDEA alone-treated rats. Treatment with yellow tea extract caused protection of superoxide dismutase (SOD) and catalase (CAT); their activity was recovered by 47% and 12%, respectively, as compared with the NDEA-treated rats. Moreover, the extract normalized the NDEA-induced activity of paraoxonase 1 (PON1) and glutathione peroxidase (GPx), while a further increase in the level of reduced glutathione (GSH) was noticed. Conclusions On the basis of these findings, it can be concluded that treatment with yellow tea partially protected the livers of rats from NDEA-induced hepatocarcinogenesis and that its antioxidant activity contributed to this effect.
authors.affiliation: a Department of Toxicology , Poznan University of Medical Sciences , Poznań , Poland ;
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Kujawska
authors.affiliation: a Department of Toxicology , Poznan University of Medical Sciences , Poznań , Poland ;
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Ewertowska
authors.affiliation: a Department of Toxicology , Poznan University of Medical Sciences , Poznań , Poland ;
authors.forename: Teresa
authors.initials: T
authors.lastname: Adamska
authors.affiliation: b Department of Pharmaceutical Biochemistry , Poznan University of Medical Sciences , Poznań , Poland ;
authors.forename: Ewa
authors.initials: E
authors.lastname: Ignatowicz
authors.affiliation: c Faculty of Food Science and Nutrition , Poznań University of Life Sciences , Poznań , Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Gramza-Michałowska
authors.affiliation: a Department of Toxicology , Poznan University of Medical Sciences , Poznań , Poland ;
authors.forename: Jadwiga
authors.initials: J
authors.lastname: Jodynis-Liebert
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000302:isolation & purification / Q000494:pharmacology*; D000975:Antioxidants / Q000302:isolation & purification / Q000494:pharmacology*; D015415:Biomarkers / Q000097:blood; D028241:Camellia sinensis / Q000737:chemistry; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D004249:DNA Damage / Q000187:drug effects; D004052:Diethylnitrosamine; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000097:blood / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects; D008517:Phytotherapy; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D050050:Protein Carbonylation / Q000187:drug effects; D017208:Rats, Wistar
chemical_list: D016588:Anticarcinogenic Agents; D000975:Antioxidants; D015415:Biomarkers; D010936:Plant Extracts; D004052:Diethylnitrosamine
keywords: Antioxidant enzymes; chemoprevention; histopathology; lipid peroxidation; oxidative stress; paraoxonase 1; polyphenols