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PubMed2001

Pyrene and chrysene fate in surface soil and sand microcosms.

Polycyclic aromatic hydrocarbons (PAHs) are major components of wastes from municipal gas plants and many wood preservatives. Soil contaminated with these wastes is a potential threat to human health because of the carcinogenicity of many PAHs. This study follows the fate of two four-ring PAHs, pyrene and chrysene, in three matrices: an adapted soil (obtained from a site contaminated with PAHs for more than 75 years), an uncontaminated soil (with and without an inoculum of adapted soil), and sand mixed with an inoculum of adapted soil. Radiolabeled pyrene, chrysene, and salicylic acid (a metabolite of PAH biodegradation) were used to trace the mineralization, transformation, extractability, and formation of an unextractable residual over time. Linear approximations of the rates of these processes were made. High-performance liquid chromatography (HPLC) analysis of extracts from inoculated soil showed the transient formation of two known metabolites: 1-hydroxypyrene (from pyrene) and 1-hydroxy-2-naphthoic acid (from chrysene). The amount of extractable label diminished steadily over the course of the study in systems that were not inhibited with sodium azide, whereas the amount of extractable label remained relatively constant in inhibited systems. Correspondingly, the amount of nonextractable residual label generally increased during each incubation in uninhibited systems, whereas the amount of this residual label remained relatively constant in inhibited systems. In contrast, the rate and extent of mineralization varied widely across matrix types. This suggests that alterations of the PAH that impact extractability and residual formation are common, in contrast to mineralization, which was apparently limited to adapted communities.

Biodegradation, Environmental↗
PubMed2002

[Determination of trace chrysene in environmental water by solid-phase microextraction coupled with high performance liquid chromatography].

A rapid method for the determination of trace chrysene in environmental water by solid-phase microextraction (SPME) coupled with high performmnce liquid chromatography (HPLC) was developed. The experimental conditions of SPME, such as extraction time, extraction temperature, effect of ion strength, desorption time, desorption solution, desorption mode and the analytical conditions of HPLC were optimized. The optimal conditions were room temperature, 1,100 r/min of stirring rate, 30 min of extraction time, 3 min of desorption time, and methanol as the desorption solution. Methanol was used as the mobile phase on a C18 reversed phase chromatographic column. The flow rate was 1 mL/min. The detection wavelength was 266 nm on a UV-Vis detector. The linear range was from 0.013 microgram/L to 3.0 micrograms/L, the detection limit was 2.7 ng/L, and the relative standard deviation (RSD) was 5.6%. The method was used for the determination of trace chrysene in tap water, mineral water, rain water and river water. The recoveries were from 103.2% to 119.3%, the RSDs were from 4.8% to 10.2%. The method is fast, convenient, sensitive, solvent-free, and suitable for the determination of trace chrysene in environmental water.

Chromatography, Gas↗
PubMed1987

Electronic considerations in the mutagenesis of some 4,5-bridged chrysenes.

The mutagenic activity of four 4,5-bridged chrysene derivatives, benz(a)aceanthrylene, and 5-methylchrysene was examined using histidine auxotrophic strains TA98 and TA100 of Salmonella typhimurium. All compounds showed a positive mutagenic response with both TA100 and TA98 in the presence of S-9. A correlation between the electronic character of the bridging group and mutagenic activity for the chrysene derivatives is proposed.

Biotransformation↗
PubMed1999

Solution conformation of the (+)-trans-anti-benzo[g]chrysene-dA adduct opposite dT in a DNA duplex.

The solution structure of the adduct derived from the covalent bonding of the fjord region (+)-(11S, 12R, 13R, 14S) stereoisomer of anti -11,12-dihydroxy-13,14-epoxy-11,12,13, 14-tetrahydrobenzo[g]chrysene, (+)- anti -B[g]CDE, to the exocyclic N(6)amino group of the adenine residue dA6, (designated (+)- trans-anti -(B[g]C)dA6), positioned opposite a thymine residue dT17 in the DNA sequence context d(C1-T2-C3-T4-C5-(B[g]C)A6-C7-T8-T9-C10-C11). d(G12-G13-A14-A15-G16-T17-G18-A19-G20++ +-A21-G22) (designated (B[g]C)dA. dT 11-mer duplex), has been studied using structural information derived from NMR data in combination with molecular dynamics (MD) calculations. The solution structure of the (+)- trans-anti -(B[g]C)dA.dT 11-mer duplex has been determined using an MD protocol where both interproton distance and dihedral angle restraints deduced from NOESY and COSY spectra are used during the refinement process, followed by additional relaxation matrix refinement to the observed NOESY intensities to account for spin diffusion effects. The results established that the covalently attached benzo[g]chrysene ring intercalates into the DNA helix directed towards the 5'-side of the modified strand and stacks predominantly with dT17 when intercalated between dC5.dG18 and (B[g]C)dA6.dT17 base-pairs. All base-pairs, including the modified (B[g]C)dA6.dT17 base-pair, are aligned through Watson-Crick pairing as in normal B -DNA. In addition, the potential strain associated with the highly sterically hindered fjord region of the aromatic portion of the benzo[g]chrysenyl ring is relieved through the adoption of a non-planar, propeller-like geometry within the chrysenyl ring system. This conformation shares common structural features with the related (+)- trans-anti -(B[c]Ph)dA adduct in the identical base sequence context, derived from the fjord region (+)-(1S,2R,3R,4S)-3, 4-dihydroxy-1,2-epoxy-1,2,3,4-tetrahydrobenzo[c]phenanthrene stereoisomer, in which intercalation is also observed towards the 5'-side of the modified dA6.dT17 base-pair.

Binding Sites↗
PubMed1977

Mutagenicity of polycyclic hydrocarbons. II. Monitoring genetical hazards of chrysene in vitro and vivo.

Mutagenicity tests were performed with chrysene in the Salmonella/microsome test, NMRI-mice oocytes, bone-marrow cells and spermatogonia of Chinese hamsters. Only in mice oocytes was a weak but significant increase of structural chromosome aberrations observed. Correlations were found between weak carcinogenic and observed weak mutagenic activities of chrysene in vitro and in vivo.

Animals↗
PubMed1993

Absence of mutagenicity of benzo[c]phenanthridine alkaloids in somatic cells of Drosophila melanogaster: comparison with 7,12-dimethylbenz[a]anthracene and chrysene.

The wing somatic mutation and recombination test (SMART) of Drosophila melanogaster was used to study the mutagenic potential of three benzo[c]phenanthridines with antileukemic properties, fagaronine, nitidine and O-methylfagaronine, as compared with that of two structurally related aromatic polycyclic hydrocarbons: 7,12-dimethylbenz[a]anthracene and chrysene. Although toxic to larvae, the benzo[c]phenanthridines and chrysene gave negative or inconclusive results while 7,12-dimethylbenz[a]anthracene was found to be highly mutagenic and recombinogenic as previously reported. These results suggest that the alkoxy groups and the quaternary nitrogen of the benzo[c]-phenanthridines may reduce or eliminate their mutagenicity in spite of their similarity to methylated polycyclic aromatic hydrocarbons.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1985

Effect of methylation on the conformer stability and reactivity of the bay-region diol-epoxides of chrysene.

The relative stabilities of conformers of the bay-region tetrahydroepoxide of methylated chrysene have been calculated. From these calculations on tetrahydroepoxides, one infers that substitution of a methyl group in the same bay-region as the epoxide should destabilize both syn-diaxial and anti-diequatorial bay-region diol-epoxide diastereomers with respect to the syn-diequatorial and anti-diaxial diastereomers. The results of these calculations, together with recent experimental observations, suggest that the enhanced in vivo binding to DNA of the isomer having the methyl group and the epoxide in the same bay-region (1,2-diol-3,4-epoxide of 5-MeC) might be partially due to this destabilization of the syn-diaxial diastereomer. The carbocation delocalization energies associated with epoxide ring opening of the methylated bay-region tetrahydroepoxide isomers of chrysene are also given.

Chemical Phenomena↗
PubMed2001

Polycyclic aromatic compounds as anticancer agents: structure-activity relationships of chrysene and pyrene derivatives.

A large number of diamides and diamines were synthesized using 6-amino chrysene and 1-amino pyrene as starting materials. A structure activity study with cis-platinum as internal control against animal and human tumor lines was carried out in vitro. This study indicated that the in vitro cytotoxicity toward these lines depends on the functionality present in the molecules. The diamino compounds were found to be more potent than the diamides, and these were equally active irrespective of the end heterocyclic group, whereas the activity of the diamides was strongly dependent on the terminal unit. In general, the diamides containing chrysene as the chromophore were more active than those with a pyrene ring. The size of the end heterocyclic ring, along with the nature of the spacer connecting the polycyclic ring to the heterocyclic ring, seemed to affect the biological activity in certain cell lines. Hemolysis experiments on a lead compound established that it had activities similar to those described for membrane-stabilizing agents. This agent also demonstrated the capacity to produce differentiation in leukemia cell lines.

Animals↗
PubMed2003

Analysis of 6-(2,2-Dichloroacetamido)chrysene interaction with the hypoxanthine phosphoribosyltransferase from Trypanosoma cruzi.

Selective inhibition is needed for drugs targeting the hypoxanthine phosphoribosyltransferase of Trypanosoma cruzi, etiologic agent of Chagas' disease. 6-(2,2-Dichloroacetamido)chrysene, was shown herein to be a selective inhibitor of the trypanosomal enzyme. SAR analysis revealed that the 6-amido moiety was essential, but the dichloroaceto moiety was not essential for achieving the low K(i) for this inhibitor. Understanding the molecular basis for these interactions could facilitate the design of selective inhibitors without a chrysene moiety.

Animals↗
PubMed2005

Convenient syntheses of dibenzo[c,p]chrysene and its possible proximate and ultimate carcinogens: in vitro metabolism and DNA adduction studies.

Dibenzo[c,p]chrysene (DB[c,p]C) is the only hexacyclic polycyclic aromatic hydrocarbon having two fjord regions, both in different chemical environments. Its environmental presence and relative tumorigenic potency are not known due to the lack of synthetic standards. We report here the synthesis of dibenzo[c,p]chrysene (1), its proximate carcinogens, i.e., trans-1,2-dihydroxy-1,2-dihydro-DB[c,p]C (2) and trans-11,12-dihydroxy-11,12-dihydro-DB[c,p]C (3), and possible ultimate carcinogens, i.e., anti-trans-1,2-dihydroxy-3,4-epoxy-1,2,3,4-tetrahydro-DB[c,p]C (4) and anti-trans-11,12-dihydroxy-13,14-epoxy-11,12,13,14-tetrahydro-DB[c,p]C (5). The syntheses of 1 and the appropriately methoxy-substituted DB[c,p]C (12 and 27), key intermediates for the synthesis of its proximate and ultimate metabolites, were tried first using a Suzuki cross-coupling reaction. However, the cyclization of olefins (10 and 11) gave poor yields of the desired products. An alternate method was thus developed employing a photochemical approach. The in vitro metabolism of DB[c,p]C was established with the S9 fraction of liver homogenate from phenobarbital/beta-naphthoflavone-induced Sprague-Dawley rats. The major dihydrodiol formed was identified as the fjord region 11,12-dihydroxy-11,12-dihydro-DB[c,p]C, while the major and minor phenols were identified as 11-hydroxy-DB[c,p]C and 12-hydroxy-DB[c,p]C, respectively. Further, the DNA adduction studies with the calf thymus DNA led to a mixture of dA and dG adducts for both fjord region diol epoxides (4 and 5). Interestingly, the dA to dG ratio for 1,2-dihydroxy-3,4-epoxide was much higher (3.2) compared to that of 11,12-dihydroxy-13,14-epoxide (0.5).

Animals↗
PubMed2000

New synthetic approaches to polycyclic aromatic hydrocarbons and their carcinogenic oxidized metabolites: derivatives of benzo[s]picene, benzo[rst]pentaphene, and dibenzo[b,def]chrysene.

A new synthetic approach to polycyclic aromatic compounds is described that entails in the key steps double Suzuki coupling of PAH bisboronic acid derivatives with o-bromoaryl aldehydes to furnish aryl dialdehydes that are converted to larger polycyclic aromatic ring systems by either (a) conversion to diolefins by Wittig reaction followed by photocyclization or (b) reductive cyclization with triflic acid and 1,3-propanediol. This synthetic method provides convenient access to as many as three different polycyclic aromatic ring systems from a single Suzuki coupled intermediate. It was utilized to synthesize substituted derivatives of benzo[s]picene, benzo[rst]pentaphene, dibenzo[b,def]chrysene, and 13,14-dihydro-benz[g]indeno[2,1-a]fluorene, as well as the putative carcinogenic bisdihydrodiol metabolites of benzo[s]picene, benzo[rst]pentaphene, and dibenzo[b,def]chrysene.

Benzopyrenes↗
PubMed1995

In vitro reaction with DNA of the fjord-region diol epoxides of benzo[g]chrysene and benzo[c]phenanthrene as studied by 32P-postlabeling.

The chemical reactivities of the optically-pure fjord-region syn- and anti-benzo[g]chrysene 11,12-dihydrodiol 13,14-epoxides (B[g]CDEs) toward DNA in vitro have been compared with those of the optically-pure fjord-region syn- and anti-benzo[c]phenanthrene 3,4-dihydrodiol 1,2-epoxides (B[c]PhDEs), using the standard 32P-postlabeling assay. The (+)-anti-, (+)-syn-, and (-)-syn-isomers of the two sets of diol epoxides showed similar extents of reaction with DNA, but the (-)-anti-B[c]PhDE was 2.5 times more reactive toward DNA than the corresponding B[g]CDE isomer and was the most reactive of the eight diol epoxides studied. When the reactions of the B[g]CDEs with DNA were analyzed by the nuclease P1-enhanced method of 32P-postlabeling, the observed adduct levels were between 3 and 10 times lower than were obtained using the standard method of 32P-postlabeling. By analyzing by TLC and HPLC the 32P-postlabeled products of the reactions of the diol epoxides with synthetic polynucleotides, the relative reactions of the B[g]CDEs and B[c]PhDEs with guanine and adenine bases in DNA were determined. All four B[g]CDE isomers reacted with adenine residues in similar proportions to those seen for the B[c]PhDE isomers. Thus, the presence of an additional benzene ring on the benzo[c]phenanthrene structure, distant from the fjord region, does not radically alter the reactivity or base selectivity of the fjord-region diol epoxides, except in the case of the (-)-anti-isomer of benzo[g]chrysene. The reasons for the lower reactivity of this isomer compared with that of the corresponding isomer of benzo[c]phenanthrene are unclear.(ABSTRACT TRUNCATED AT 250 WORDS)

Autoradiography↗
PubMed1995

Characterization of DNA adducts formed by anti-benzo[g]chrysene 11,12-dihydrodiol 13,14-epoxide.

The anti-11,12-dihydrodiol 13,14-epoxide of benzo[g]chrysene, a fjord-region-containing hydrocarbon, was found to react with DNA in vitro to yield, as the major product, an adduct in which the epoxide of the 11R, 12S, 13S, 14R enantiomer was opened trans by the amino group of deoxyadenosine. The structures of this adduct and other deoxyadenosine and deoxyguanosine adducts were established by spectroscopic methods. In reactions with deoxyguanylic acid, a product tentatively identified as a 7-substituted guanine was also detected. The mutagenic properties of this dihydrodiol epoxide in shuttle vector pSP189 showed that mutation at AT pairs accounted for 39% of base change mutations whereas chemical findings indicated that about 60% of adducts formed in calf thymus DNA involved adenines. Since calf thymus DNA is 56% AT and the target supF gene is 41% AT, the findings represent a fairly close relationship between adduct formation and mutagenic response. Overall, the chemical and mutagenic selectivities for the two purine bases in DNA were similar, though not identical, to those for the only other fjord-region-containing hydrocarbon studied in depth, i.e., benzo[c]phenanthrene. A major difference for these two hydrocarbon derivatives, however, is that benzo[c]phenanthrene dihydrodiol epoxides react to much higher extents (approximately 4-fold) with DNA than did the benzo[g]chrysene derivative.

Base Sequence↗
PubMed1981

Metabolic conversion of dibenz[a,h]anthracene (+/-)trans-1,2-dihydrodiol and chrysene (+/-)trans-3,4-dihydrodiol to vicinal dihydrodiol epoxides.

The hydroxyl groups of dibenz[a,h]anthracene trans-1,2-dihydrodiol and chrysene trans-3,4-dihydrodiol are known to be predominantly in quasi-axial conformations. These dihydrodiols were metabolized by liver microsomes from 3-methylcholanthrene-pretreated rats to form 1,2,3,4-tetrahydrotetrols as the major products. The major metabolites of the dihydrodiols were isolated by reversed-phase high-performance liquid chromatography and identified by ultraviolet--visible absorption and mass spectral analyses. The results indicate that axial hydroxyl groups of dibenz[a,h]anthracene trans-1,2-dihydrodiol and of chrysene trans-3,4-dihydrodiol do not direct metabolism away from their respective vicinal double bond.

Animals↗
PubMed1993

Sulfotransferase-mediated mutagenicity of 1-hydroxymethylpyrene and 4H-cyclopenta[def]chrysen-4-ol and its enhancement by chloride anions.

1-Hydroxymethylpyrene (HMP), a primary benzylic alcohol, and 4H-cyclopenta[def]chrysen-4-ol (OH-CPC), a secondary benzylic alcohol, were investigated for mutagenicity in Salmonella typhimurium (reversion of the his- strain TA98) in the presence of various xenobiotic-metabolizing systems. In the direct test, HMP was inactive and OH-CPC was very weakly active. In the presence of NADPH-fortified postmitochondrial fraction from rat liver (S9/NADPH), no activation of OH-CPC was observed, whereas strong mutagenic effects were elicited by HMP. In the presence of cytosol and 3'-phosphoadenosine-5'-phosphosulfate (PAPS), both alcohols were activated to potent mutagens. For equal mutagenic effects, approximately 650-fold lower concentrations of HMP were required in the cytosol/PAPS-mediated assay than in the S9/NADPH-mediated assay. The cytosol/PAPS-mediated mutagenicity of both alcohols was 3- to 4-fold enhanced, when KCl (125 mM) was present during the exposure. The authentic chloromethylarenes, 1-chloromethylpyrene and 4-chloro-4H-cyclopenta[def]chrysene, showed very strong direct mutagenicity. These results, taken together with previous findings, indicate that both primary and secondary benzylic alcohols derived from polycyclic aromatic hydrocarbons may be activated by sulfotransferases to electrophilic sulfuric acid esters, and by subsequent substitution reaction to further active species such as benzylic chlorides.

Chrysenes↗
PubMed1996

Covalent DNA adducts formed in mouse epidermis by benzo[g]chrysene.

The metabolic activation in mouse skin of benzo[g]chrysene (B[g]C), a moderately carcinogenic polycyclic aromatic hydrocarbon (PAH) present in coal tar, was investigated. Male Parkes mice were treated topically with 0.5 micromol B[g]C and DNA was isolated from the treated areas of skin at various times after treatment and analysed by 32P-post-labelling. Seven major adduct spots were detected, at a maximum level of 6.55 fmol adducts/microg DNA. Mouse skin treated with the PAH benzo[c]phenanthrene (B[c]Ph) gave a total of 0.24 fmol adducts/microg DNA. B[g]C-DNA adducts persisted in skin for at least 3 weeks. Treatment of mice with 0.5 micromol of the optically pure putative proximate carcinogens, the (+)- and (-)-trans benzo[g]chrysene-11,12-dihydrodiols, led to the formation of adducts which comigrated on TLC and HPLC with those formed in B[g]C-treated mice, which suggested that the detected adducts were formed by the fjord region B[g]C-11,12-dihydrodiol-13,14-epoxides (B[g]CDEs). To test this, the four optically pure synthetic B[g]CDEs were reacted in vitro with DNA and the heteroco-polymers poly(dA x dT) and poly(dG x dC) and these samples 32P-postlabelled. Co-chromatography, on both TLC and HPLC, of in vitro and in vivo adducts indicated that B[g]C is activated in mouse skin through formation of the (-)-anti-(11R,12S,l3S,14R) and (+)-syn-(11S,12R,13S,14R) B[g]CDEs. (-)-anti-B[g]CDE formed five adducts with DNA, two of them with adenine and three with guanine bases. (+)-syn-B[g]CDE formed one adduct with each of these bases in DNA. The adenine adducts accounted for 64% of the total major adducts formed in B[g]C-treated mouse skin. The route of metabolic activation or B[g]C is similar to that reported for B[c]Ph, but the extent of activation to the fjord region diol-epoxides is significantly greater in the case of B[g]C, as demonstrated by the higher levels of adduct formation in vivo.

Animals↗
PubMed1999

Specificity of murine glutathione S-transferase isozymes in the glutathione conjugation of (-)-anti- and (+)-syn-stereoisomers of benzo[g]chrysene 11,12-diol 13,14-epoxide.

Specificities of murine glutathione (GSH) S-transferase (GST) isozymes mGSTA1-1, mGSTA2-2, mGSTA3-3 and mGSTA4-4 (alpha class), mGSTP1-1 (pi class) and mGSTM1-1 (mu class) for GSH conjugation of (-)-anti- and (+)-syn-stereoisomers of benzo[g]chrysene 11, 12-diol 13,14-epoxide (B[g]CDE), the activated metabolites of the environmental pollutant benzo[g]chrysene (B[g]C), have been determined. When GST activity was determined as a function of varying (-)-anti- or (+)-syn-B[g]CDE concentration (10-320 microM) at a fixed saturating concentration of GSH (2 mM), each isozyme obeyed Michaelis-Menten kinetics. mGSTA1-1 was significantly more efficient than other murine GSTs in the GSH conjugation of not only (-)-anti-stereoisomer but also (+)-syn-B[g]CDE. For example, the catalytic efficiency (k(cat)/K(m)) of mGSTA1-1 towards (-)-anti-B[g]CDE was approximately 2.3- to 16.6-fold higher compared with other murine GSTs. Likewise, mGSTA1-1 was approximately 2.7-, 6.7-, 4.4- and 12.4-fold more efficient than mGSTA2-2, mGSTA3-3, mGSTP1-1 and mGSTM1-1, respectively, in catalyzing the GSH conjugation of (+)-syn-B[g]CDE. Interestingly, mGSTA4-4, which also belongs to class alpha, was virtually inactive towards both stereoisomers of B[g]CDE. The results of the present study indicate that murine GSTs, especially alpha class isozymes, significantly differ in their ability to detoxify B[g]CDE stereoisomers and that mGSTA1-1 plays a major role in the detoxification of both (-)-anti- and (+)-syn-B[g]CDE, which among four B[g]CDE stereoisomers are formed from the carcinogen B[g]C as major DNA binding metabolites.

Animals↗
PubMed1982

The metabolic activation of chrysene by hamster embryo cells.

The major deoxyribonucleoside--hydrocarbon adducts present in hydrolysates of DNA isolated from hamster embryo cells treated with chrysene were examined by chromatography on Sephadex LH20 and by h.p.l.c. on Zorbax ODS. The results show that both major adducts have chromatographic properties identical to those of adducts formed when r-1,t-2-dihydroxy-t-3,4-oxy-1,2,3,4-tetrahydrochrysene reacts with DNA and provide evidence that metabolic activation of chrysene occurs via the formation of this 'bay-region' diol-epoxide.

Animals↗