title: Metabolism of the alpha,beta-unsaturated ketones, chalcone and trans-4-phenyl-3-buten-2-one, by rat liver microsomes and estrogenic activity of the metabolites.
abstract: When chalcone and trans-4-phenyl-3-buten-2-one (PBO) were incubated with liver microsomes of untreated rats in the presence of NADPH, 4-hydroxychalcone and trans-4-(4-hydroxyphenyl)-3-buten-2-one (4-OH-PBO), respectively, were formed as major metabolites. Two minor metabolites of chalcone, 4'-hydroxychalcone and 2-hydroxychalcone, were also observed. The oxidase activity affording 4-hydroxychalcone was inhibited by SKF 525-A, disulfiram, ketoconazole, and alpha-naphthoflavone. The oxidase activities leading to 4-hydroxychalcone and 4'-hydroxychalcone were enhanced in liver microsomes of 3-methylcholanthrene- and phenobarbital-treated rats, respectively. The activity generating 2-hydroxychalcone was enhanced in liver microsomes of 3-methylcholanthrene- and dexamethasone-treated rats. The oxidation of PBO to 4-OH-PBO was inhibited by SKF 525-A, ketoconazole, disulfiram, and sulfaphenazole. This activity was enhanced in liver microsomes of 3-methylcholanthrene-, acetone- and phenobarbital-treated rats. 4-Hydroxylation, 4'-hydroxylation, and 2-hydroxylation of chalcone were catalyzed by rat recombinant cytochrome P450 1A1, 1A2, and 2C6; by 1A1 and 2C6; and by 1A1 and 3A1, respectively. PBO was oxidized by cytochrome P450 1A1, 1A2, 2C6, and 2E1. Chalcone and PBO were negative in an estrogen reporter assay using estrogen-responsive human breast cancer cell line MCF-7. However, 4-hydroxychalcone, 2-hydroxychalcone, 4'-hydroxychalcone, and 4-OH-PBO exhibited estrogenic activity.
authors.affiliation: Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Kohno
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Kitamura
authors.forename: Seigo
authors.initials: S
authors.lastname: Sanoh
authors.forename: Kazumi
authors.initials: K
authors.lastname: Sugihara
authors.forename: Nariaki
authors.initials: N
authors.lastname: Fujimoto
authors.forename: Shigeru
authors.initials: S
authors.lastname: Ohta
mesh_terms: D000818:Animals; D001711:Biotransformation; D002074:Butanones / Q000378:metabolism*; D045744:Cell Line, Tumor; D002599:Chalcone / Q000378:metabolism*; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis / Q000378:metabolism*; D004790:Enzyme Induction; D004967:Estrogens / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000378:metabolism; D007654:Ketoconazole / Q000494:pharmacology; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008156:Luciferases; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism; D011335:Proadifen / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020218:Response Elements; D014162:Transfection
chemical_list: D002074:Butanones; D065607:Cytochrome P-450 Enzyme Inhibitors; D004967:Estrogens; D007527:Isoenzymes; D002599:Chalcone; D003577:Cytochrome P-450 Enzyme System; D011335:Proadifen; C025383:benzylideneacetone; D008156:Luciferases; D007654:Ketoconazole