title: Suppressive components in rice husk against mutagens-induced SOS response using Salmonella typhimurium TA1535/pSK1002 umu test.
abstract: The EtOAc extract from rice (Oriza sativa cv. Hinohikari) husk showed a suppressive effect on umu gene expression of the SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen, Trp-P-1, which requires liver metabolizing enzyme. To obtain the suppressive compound, the EtOAc extract was fractionated by SiO(2) column chromatography using umu test as a bioassay guide. Suppressive compound was isolated and identified as momilactone A (1) by EIMS, IR, (1)H- and (13)C-NMR spectroscopy. Compound 1 inhibited of the SOS-inducing activity of Trp-P-1 in the umu test. Gene expression was suppressed by 32.6% at less than 0.60 mM. Compound 1 was assayed with activated Trp-P-1. The suppressive effect of Compound 1 was decreased compared with that of Trp-P-1. Furthermore, 1 was assayed with another mutagens, such as MeIQ, activated MeIQ, furylfuramide (AF-2), MNNG, and UV-irradiation. Compound 1 showed greater suppressive effect on AF-2-inducing SOS response than other mutagens.
authors.affiliation: Faculty of Science and Engineering, Department of Applied Chemistry, Kinki University Kowakae, Higashiosaka-shi, Osaka.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Okuno
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Miyazawa
mesh_terms: D002243:Carbolines; D009152:Mutagenicity Tests; D012275:Oryza / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D013014:SOS Response, Genetics / Q000187:drug effects*; D012486:Salmonella typhimurium / Q000187:drug effects*
chemical_list: D002243:Carbolines; D010936:Plant Extracts; C019132:3-amino-1,4-dimethyl-5H-pyrido(4,3-b)indole