title: Therapeutic efficacy of green tea polyphenols on cellular thiols in 4-Nitroquinoline 1-oxide-induced oral carcinogenesis.
abstract: In cancer, a high flux of oxidants not only depletes the cellular thiols, but damages the whole cell as well. Epidemiological studies suggest green tea may mitigate cancers in human and animal models for which several mechanisms have been proposed. In the present investigation, the levels of cellular thiols such as reduced glutathione (GSH), oxidised glutathione (GSSG), protein thiols (PSH), total thiols, lipid peroxidation product conjugated dienes and the activity of gamma glutamyl transferase (GGT) were assessed in tongue and oral cavity. In 4-Nitroquinoline 1-oxide- (4-NQO) induced rats, there was a decrease in the levels of GSH, PSH and total thiols and an increase in the levels of GSSG, conjugated dienes and the activity of GGT. On supplementation of green tea polyphenols (GTP) for 30 days (200 mg/kg) for the oral cancer-induced rats, there was a moderate increase in the levels of GSH, PSH and total thiols and a decrease in the levels of GSSG, conjugated dienes and the activity of GGT. Thus, GTP reduces the oxidant production thereby maintains the endogenous low molecular weight cellular thiols in oral cancer-induced rats. From the results, it can be concluded that GTP supplementation enhances the cellular thiol status thereby mitigate oral cancer.
authors.affiliation: Department of Biochemistry, University of Madras, Guindy Campus, Chennai-600025,Tamilnadu, India.
authors.forename: Periasamy
authors.initials: P
authors.lastname: Srinivasan
authors.forename: Kuruvimalai Ekambaram
authors.initials: KE
authors.lastname: Sabitha
authors.forename: Chennam Srinivasulu
authors.initials: CS
authors.lastname: Shyamaladevi
mesh_terms: D015112:4-Nitroquinoline-1-oxide; D000818:Animals; D002273:Carcinogens; D002294:Carcinoma, Squamous Cell / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology* / Q000627:therapeutic use; D005978:Glutathione / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D009062:Mouth Neoplasms / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D010636:Phenols / Q000494:pharmacology* / Q000627:therapeutic use; D008517:Phytotherapy / Q000379:methods*; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D059808:Polyphenols; D051381:Rats; D017208:Rats, Wistar; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013662:Tea / Q000737:chemistry*; D005723:gamma-Glutamyltransferase / Q000378:metabolism
chemical_list: D002273:Carcinogens; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols; D013438:Sulfhydryl Compounds; D013662:Tea; D015112:4-Nitroquinoline-1-oxide; D005723:gamma-Glutamyltransferase; D005978:Glutathione