title: Inhibitory effect of hemin, chlorophyllin and related pyrrole pigments on the mutagenicity of benzo[a]pyrene and its metabolites.
abstract: Hemin and chlorophyllin are known to inhibit strongly the mutagenicity of benzo[a]pyrene in the Salmonella assay. To further investigate this phenomenon, a series of these pyrrole pigments including pure samples of Cu- and Fe-chlorins were tested for their potency to inhibit the mutagenicity of benzo[a]pyrene and its metabolites, benzo[a]pyrene-7,8-diol, benzo[a]pyrene-4,5-epoxide, and benzo[a]pyrene-7,8-diol-9,10-epoxide. Hemin was the most potent among the pigments tested for these inhibitions. Both hemin and Cu-chlorin accelerated efficiently the degradation of benzo[a]pyrene-7,8-diol-9,10-epoxide, and this acceleration seemed to be the predominant mechanism by which these pigments inhibit the overall mutagenicity of benzo[a]pyrene in Salmonella. Based on spectroscopic evidence, we speculate that a complex formation between hemin and benzo[a]pyrene-7,8-diol-9,10-epoxide takes place and that this complexing is the cause of the accelerated degradation.
authors.affiliation: Faculty of Pharmaceutical Sciences, Okayama University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Arimoto
authors.forename: K
authors.initials: K
authors.lastname: Kan-yama
authors.forename: H
authors.initials: H
authors.lastname: Rai
authors.forename: H
authors.initials: H
authors.lastname: Hayatsu
mesh_terms: D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide / Q000378:metabolism; D016587:Antimutagenic Agents / Q000378:metabolism / Q000494:pharmacology*; D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors; D001564:Benzo(a)pyrene / Q000031:analogs & derivatives / Q000378:metabolism*; D001580:Benzopyrenes / Q000378:metabolism; D001711:Biotransformation; D002735:Chlorophyllides / Q000378:metabolism / Q000494:pharmacology*; D018736:DNA Adducts / Q000378:metabolism; D005290:Ferric Compounds / Q000378:metabolism / Q000494:pharmacology; D006427:Hemin / Q000378:metabolism / Q000494:pharmacology*; D008665:Metalloporphyrins / Q000378:metabolism / Q000494:pharmacology; D009152:Mutagenicity Tests; D009153:Mutagens / Q000378:metabolism*; D010860:Pigments, Biological / Q000378:metabolism / Q000494:pharmacology*; D011758:Pyrroles / Q000378:metabolism / Q000494:pharmacology*; D012486:Salmonella typhimurium / Q000187:drug effects
chemical_list: D016587:Antimutagenic Agents; D001580:Benzopyrenes; D002735:Chlorophyllides; D018736:DNA Adducts; D005290:Ferric Compounds; D008665:Metalloporphyrins; D009153:Mutagens; D010860:Pigments, Biological; D011758:Pyrroles; C043931:benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide-DNA; C059624:ferric chlorin; D001564:Benzo(a)pyrene; D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; C021338:3-hydroxybenzo(a)pyrene; D006427:Hemin; D001189:Aryl Hydrocarbon Hydroxylases; C007020:chlorophyllin