title: Potent suppressing activity of the non-polyphenolic fraction of green tea (Camellia sinensis) against genotoxin-induced umu C gene expression in Salmonella typhimurium (TA 1535/pSK 1002)--association with pheophytins a and b.
abstract: Antigenotoxic and antimutagenic activities of green tea extract and tea-derived polyphenols have been studied using in vitro and in vivo experiments. However, antigenotoxic substances in the non-polyphenolic fraction of green tea have been poorly elucidated. In the present study, the effect of the non-polyphenolic fraction of green tea on genotoxin-induced umu C gene expression was analyzed using a tester bacteria, and potent antigenotoxic substances in the non-polyphenolic fraction were identified. The non-polyphenolic fraction of green tea showed strong suppressive activities against umu C gene expression in Salmonella typhimurium (TA 1535/pSK 1002) induced by 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indol (Trp-P-1) or mitomycin C (MMC) in the presence or absence of S9 metabolizing enzyme mixture. The non-polyphenolic fraction of green tea exhibited major two-color bands in a silica gel TLC and they were identified as chlorophyll-related compounds, pheophytins a and b, judged by their specific colors, Rf values in silica gel TLC and absorption spectra. These pigments showed significant suppressive activities against umu C gene expression in tester bacteria induced by Trp-P- and MMC in a dose-dependent manner. These results suggest that the non-polyphenolic fraction of green tea contains pheophytins a and b as potent antigenotoxic substances.
authors.affiliation: Department of Human Life Science, Osaka Kun-Ei Women's College, Set's City, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Okai
authors.forename: K
authors.initials: K
authors.lastname: Higashi-Okai
mesh_terms: D016587:Antimutagenic Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics*; D004259:DNA-Directed DNA Polymerase; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D010674:Pheophytins / Q000494:pharmacology*; D013014:SOS Response, Genetics / Q000187:drug effects; D012486:Salmonella typhimurium / Q000235:genetics*; D018724:Spinacia oleracea / Q000737:chemistry; D013662:Tea / Q000737:chemistry*
chemical_list: D016587:Antimutagenic Agents; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D010674:Pheophytins; D013662:Tea; C078202:UmuC protein, E coli; D004259:DNA-Directed DNA Polymerase