title: Metabolism of isomeric nitrobenzo[a]pyrenes leading to DNA adducts and mutagenesis.
abstract: We have been interested in determining the structural and electronic features that may be useful in predicting the mutagenic activity of nitro-polycyclic aromatic hydrocarbons (nitro-PAHs). We have previously found that a correlation between structural and electronic features and direct-acting mutagenicity in Salmonella typhimurium cannot be made using nitro-PAHs with different molecular size. In this study, a series of structurally related nitro-PAHs, the environmental contaminants 1-, 3-, and 6-nitrobenzo[alpha]pyrene (NBaP) and their derivatives, was used to determine structure-activity relationships. It was found that isomeric NBaPs are activated to DNA damaging and mutagenic derivatives by nitroreduction, ring-oxidation, or by a combination of these two pathways. A general finding was that NBaPs and derivatives with their nitro substituent oriented perpendicular to the aromatic system exhibit either very weak or no direct-acting mutagenicity in S. typhimurium strains TA98 and TA100. In this paper, we also discuss the effect of the location of the nitro group on the metabolism and the mutagenicity of NBaPs and the effect of oxygen-containing functional groups on the mutagenicity of NBaP derivatives. These findings provide a useful molecular basis for interpreting and predicting the direct-acting mutagenicity of nitro-PAHs.
authors.affiliation: Department of Health and Human Services, Food and Drug Administration, National Center for Toxicological Research, Division of Biochemical Toxicology, Jefferson, AR 72079, USA.
authors.forename: P P
authors.initials: PP
authors.lastname: Fu
authors.forename: F Y
authors.initials: FY
authors.lastname: Qui
authors.forename: H
authors.initials: H
authors.lastname: Jung
authors.forename: L S
authors.initials: LS
authors.lastname: Von Tungeln
authors.forename: D J
authors.initials: DJ
authors.lastname: Zhan
authors.forename: M J
authors.initials: MJ
authors.lastname: Lee
authors.forename: Y S
authors.initials: YS
authors.lastname: Wu
authors.forename: R H
authors.initials: RH
authors.lastname: Heflich
mesh_terms: D000818:Animals; D001580:Benzopyrenes / Q000378:metabolism; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D018736:DNA Adducts; D007536:Isomerism; D008862:Microsomes, Liver / Q000378:metabolism; D009152:Mutagenicity Tests; D009153:Mutagens; D009566:Nitrates / Q000378:metabolism*; D011083:Polycyclic Compounds / Q000378:metabolism*; D051381:Rats; D012486:Salmonella typhimurium / Q000235:genetics; D013329:Structure-Activity Relationship
chemical_list: D001580:Benzopyrenes; D018736:DNA Adducts; D009153:Mutagens; D009566:Nitrates; D011083:Polycyclic Compounds; C034699:6-nitrobenzo(a)pyrene