Tumorigenicity of Fjord Region Diol Epoxides of Polycyclic Aromatic Hydrocarbons

(±)-anti-Benzo[c]phenanthrene-3,4-diol-1,2-epoxide (BcPDE), (±)-anti-benzo[g]-chrysene-11,12-diol-13,14-epoxide (BgCDE), and (±)-anti-dibenzo[a,l]pyrene-11,12-diol-13,14-epoxide (DB[a,l]PDE) were synthesized for use in biological assays. To compare mammary carcinogenicity, BcPDE and (±)-anti-benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE) were tested by direct application to the mammary glands of female CD rats at a total dose of 12.2 μmol per animal. 6-Nitrochrysene (6-NC) at the same dose was used as a positive control. BcPDE was found to be a potent mammary tumorigen and carcinogen, inducing significantly more fibroadenomas and adenocarcinomas than the other two compounds. In a second bioassay, BcPDE, BgCDE, and DB[a,l]PDE at a total dose of 1.2 μmol were compared. All three diol epoxides were potent mammary carcinogens and based on the collective results to date, the relative carcinogenic activities of the diol epoxides can be approximated as DB[a,l]PDE>BcPDE>BgCDE>BPDE.

To determine tumorigenic potencies in newborn mice, BPDE was compared with BgCDE, DB[a,l]PDE, and BcPDE at a total dose of 25 nmol per mouse, administered on days 1, 7, and 15 of life. BgCDE and BcPDE had similar potency in inducing lung tumors. BgCDE induced more liver tumors in male mice than BcPDE. Both compounds were more tumorigenic than BPDE. DB[a,l]PDE was highly toxic at 25 nmol and all animals died within one week after the first dose. DB[a,l]PDE was also tested at total intended doses of 5 nmol and 1 nmol. Due to high toxicity, only the first dose of the intended 5 nmol was given. This dose as well as the 1 nmol total dose caused significant incidence and multiplicity of lung tumors.

These results support the hypothesis that sterically hindered fjord region diol epoxides are potent mammary carcinogens in CD rats and strong lung tumorigens in newborn mice.     

Time-Integrated DNA Adduct Levels and Relative Tumorigenic Potencies of Six Polycyclic Aromatic Hydrocarbons in Strain A/J Mouse Lung

We have investigated the induction of DNA adducts and adenomas in the lungs of strain A/J mice following the i.p. administration of several polycyclic aromatic hydrocarbons (PAH): pyrene, dibenz[a,h]anthracene (DBA), benzo[a]pyrene (B[a]P), benzo[b]fluoranthene (B[b]F), 5-methylchrysene (5-MeC), 3-methylcholanthrene (3-MC), and cyclopenta[cd]pyrene (CPP). All of the PAH induced lung adenomas, with relative tumor potency rankings as a function of administered dose: DBA = 3-MC > 5-MeC > CPP > B[a]P > B[b]F. DNA adducts reached maximal levels between 3 and 7 days after injection, followed by a gradual decrease. The time-integrated DNA adduct level (TIDAL) was calculated by numerically integrating the areas under the adduct persistence curves extrapolated out to 240 days for each PAH at each dose level. Tumorigenic potencies as a function of TIDAL values for 5-MeC, B[a]P, B[b]F, and CPP were all equal, while 3-MC was 2.6-fold more potent and DBA was 25.8-fold more potent.     

Detection of Reactive Quinones in the Metabolism of Polycyclic Aromatic Hydrocarbons by the Formation of their Glutathione Conjugates

The biotransformation of polycyclic aromatic hydrocarbons to quinones by rat liver microsomes was investigated. The employment of an electrochemical detector allowed the specific detection of quinones separated by reverse phase HPLC with higher sensitivity as compared to UV detection. Microsomal incubations of benzo[a]pyrene (BP) resulted in the formation of 1,6-, 3,6- and 6,12-quinones, of naphthalene in the detection of naphthalene-1,4-quinone, whereas ortho-quinones could only be detected in trace amounts. Additional protein binding studies showed that only 9–22% of synthetic ortho-quinones could be recovered from microsomal incubations. In order to scavenge possible reactive quinone metabolites with glutathione (GSH) and to identify these metabolites, GSH-conjugates of naphthalene-1,2-quinone, naphthalene-1,4-quinone, chrysene-1,2-quinone, BP-7,8-quinone and BP-9,10-quinone were synthesized and spectroscopically characterized. After incubations of 1-naphthol or naphthalene with rat liver microsomes the GSH conjugate of naphthalene-1,2-quinone could be identified by cochromatography with the authentic reference compound.     

Polycyclic Aromatic Hydrocarbons in Agroecosystems - Example of Poland

Evaluation of the content of polycyclic aromatic hydrocarbons (PAHs) in agricultural soils in Poland was performed on the basis of the results of three separate investigation programmes carried out in the years 1992-1997. Two of the programmes were restricted to small regions of different exposition to anthropogenic activity, the third one covered country-wide scale. The results confirm high point contamination in areas situated in the proximity of industrial/municipal/transport pollution sources. Arable soils from rural regions were characterised by very low contamination with PAHs with median content of σ 13PAH 180 μg/kg. The usefulness of the existing European criteria for the evaluation of soil contamination with PAHs was discussed.     

Chlorinated Polycyclic Aromatic Hydrocarbons Associated with Drinking Water Disinfection: Synthesis,Formation under Aqueous Chlorination Conditions and Genotoxic Effects

Polycyclic aromatic hydrocarbons (PAHs) are among the most persistent and toxic organic micropollutants present in water and several of them are mutagenic and carcinogenic. Although it has been shown that chlorinated derivatives of PAHs (Cl-PAHs) may be formed during the water chlorination procedure, little is known about their potential genotoxic and carcinogenic effects. The objectives of the present work were to prepare and characterize the major chlorinated derivatives of benzo[a]pyrene (BaP) and fluoranthene (Fluo), to develop an analytical methodology for their quantification in water samples and to analyse their potential genotoxicity. Chlorinated standards were prepared by a newly developed two phase method (water/n-hexane) using sodium hypochlorite. 6-Chloro-benzo[a]pyrene was selectively obtained from BaP, while 1,3-dichloro-fluoranthene and 3-chloro-fluoranthene were obtained from Fluo. All products were isolated and characterized by nuclear magnetic resonance and mass spectrometry. The formation of BaP- and Fluo-chlorinated derivatives under aqueous chlorination conditions was observed using a SPE-HPLC-FLD methodology. In addition, the cytotoxic and genotoxic activities of the three chlorinated derivatives were analyzed in comparison to their parent compounds, in a human-derived hepatoma cell line using the neutral red uptake and comet assays, respectively. The results showed that, at the equimolar doses of 100 and 125 μM, 6-Cl-BaP was able to induce a significantly higher level of DNA damage than BaP, suggesting a more potent genotoxic effect. In contrast, neither Fluo nor its chlorinated derivatives were genotoxic in the same cell line. The identification of new and possibly hazardous water chlorination by-product from PAHs emphasizes the need to minimize total organic carbon content of raw water and the implementation of safer water disinfection methods.     

NMR Conformational Analysis of DNA Duplexes Containing Diol Epoxide Adducts of Polycyclic Aromatic Hydrocarbons

The principal adducts formed between DNA and polycyclic aromatic hydrocarbon diol epoxides result from N-alkylation of the exocyclic amino groups of the purine bases by the benzylic carbon atom of the epoxide. To date, the solution conformations of more than a dozen alkylated DNA duplexes have been examined by 2D NMR spectroscopy. For trans opened diol epoxides, oligomer duplexes containing N²-adducts at deoxyguanosine have the hydrocarbon residue lying in the minor groove whereas those containing N⁶-adducts at deoxyadenosine have the hydrocarbon intercalated within the DNA helix. Absolute configuration at the site of attachment appears to be a major determinant in establishing whether the hydrocarbon lies to the 3′- or the 5′-side of the adducted base. For trans opened deoxyadenosine adducts with R-absolute configuration, the hydrocarbon residue is positioned toward the 5′-end of the adducted strand whereas trans opened deoxyguanosine adducts with R-absolute configuration have the hydrocarbon located toward the 3′-end of the adducted strand.     

Ozonation of Polycyclic Aromatic Hydrocarbons in Water Solution

The degradation of three polycyclic aromatic hydrocarbons (PAHs): benzo[a]pyrene (BAP), chrysene (CHR), and fluorene (FLU) in aqueous solution using ozone was investigated. The influence of pH of the reaction mixture, ozone concentration, and the presence of a radical scavenger on the reaction rate was determined. The highest rate of PAHs disappearance was achieved in acidic solutions. The radical scavenger, tert-butanol, effectively inhibited the rate of PAHs destruction. The rate constants of direct reaction of PAHs with ozone were calculated and they were equal to (3.32 ± 0.21) × 10⁴; (1.10 ± 0.15) × 10⁴ and 44.8 ± 1.1 M^?1s^?1 for BAP, CHR, and FLU, respectively. The contributions of direct ozonolysis, and radical reaction to PAHs oxidation in ozonation processes, were evaluated.     

Effect of the Route of Administration on the Induction of Cytogenetic Damage and DNA Adducts in Peripheral Blood Lymphocytes of Rats and Mice by Polycyclic Aromatic Hydrocarbons

Experiments were designed to investigate how the route of exposure to polycyclic aromatic hydrocarbons (PAHs) in mice and rats affects the induction of cytogenetic end points and DNA adduction. Both mice and rats were exposed to 100 mg/kg of benz[ a ]anthracene (B[ a ]A), benzo[ b ]fluoranthene (B[ b ]F), benzo[ a ]pyrene (B[ a ]P), or chrysene (Chr) by gavage or by intraperitoneal injection (i.p.). Peripheral blood was removed by cardiac puncture 7 days after PAH administration. Blood samples were analyzed in parallel for sister chromatid exchange (SCE) frequency, the frequency of micronuclei in cytochalasin B-induced binucleate cells (MN bn ), and DNA adduction using 32P-postlabeling. The i.p. route of exposure produced both the highest levels of cytogenetic damage and DNA adducts for each PAH. The mouse was more sensitive than the rat to PAH exposure as measured by SCE induction and the total amount of DNA adducts/ w g DNA.     

Fluorescence and Raman Spectrometry of Polycyclic Aromatic Hydrocarbons in Biological Systems

Abstract

Fluorescence and Raman spectrometry were employed for the study of interactions of benzo[a]pyrene and pyrene with heme proteins in the presence of phospholipids. Since BP is asymmetrical and pyrene is symmetrical, dual maxima bands appear in the excimer of BP molecules and one single band in the excimer of pyrene. The metabolized BP molecules may mainly derive from the bilayer surface and with a proper orientation. BP molecules in other sites in the membrane will have to be transferred to these sites in order to be metabolized.     

Isolation and some Properties of Bacteria that Degrade Polycyclic Aromatic Hydrocarbons

Four bacteria, which could grow on pyrene as the sole source of carbon, were isolated from soil from an urban area in Tokyo. One of them, strain H2-5, was a rod bacterium that was positive in gram staining and in acid-fast staining. The optimum growth temperature was 34-35°C, and the upper limit temperature for the growth was around 45°C. At a concentration of 1.3 μg/ml polycyclic aromatic hydrocarbon (PAH), H2-5 cells (45 μg dry weight/ml) grown on Tryptic Soy Broth made disappear 90% of pyrene in 12 hr, and Benzo(a)pyrene (BaP), Benz(a)-anthracene (BaA), and Benzo(ghi)perylene individually disappeared 60%, 25%, and 8%, respectively, in 3 days. PAHs in the extract by dichloromethane from airborne particles in approximately 5 m³ of air disappeared by the action of H2-5 as follows: pyrene, 100% in 3 days; BaA and BaP, 70% and 71%, respectively, in 4 days. Pyrene in tarry matter extracted from soil disappeared 88% in 4 days.     

Contamination of Soil by Polycyclic Aromatic Hydrocarbons in Some Urban Areas

The contamination by 16 polycyclic aromatic hydrocarbons (PAHs) in surface soils, sampled at a 0-5 cm depth in the urban areas of Tallinn, Helsinki, Vilnius, Chicago, London is reported. All samples were analyzed using the same protocol. The median concentrations ( w g/kg) were found to be 117, 539, 127, 3,263, 1,728 for pyrene; 62, 236, 43, 1,634, 1,652 for benzo[ a ]pyrene; 86, 304, 92, 2,295, 2,068 for benzo[ a ]pyrene toxic equivalents, calculated using the benzo[ a ]pyrene toxic equivalency factors; 467, 1,471, 392, 8,981, 6,837 for a total of seven probable human carcinogenic PAHs: benzo[ a ]anthracene, chrysene, benzo[ b ]fluoranthene, benzo[ k ]fluoranthene, benzo[ a ]pyrene, dibenz[ ah ]anthracene, indeno[1,2,3- cd ]pyrene; 911, 2,941, 672, 16,183, 13,718 for the total of 16 PAHs, recommended by the U.S. Environmental Protection Agency: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[ a ]anthracene, chrysene, benzo[ b ]fluoranthene, benzo[ k ]fluoranthene, benzo[ a ]pyrene, dibenz[ ah ]anthracene, benzo[ ghi ]perylene, indeno[1,2,3- cd ]pyrene in Tallinn ( n = 3), Helsinki ( n = 3), Vilnius ( n = 15), Chicago ( n = 4), London ( n = 3), respectively. The size of the population is a statistically significant factor in urban soil contamination by high-molecular-mass PAHs.     

Relationship Between Urinary Levels of 1-Hydroxypyrene and 3-Hydroxybenzo[ a ]pyrene for Workers Exposed to Polycyclic Aromatic Hydrocarbons

Biomonitoring of workers was carried out in three working areas--an artificial target factory, an aluminum plant, and an electrometallurgy plant--to assess exposure to PAHs. All the 48 hr-voided urine samples of the exposed workers were collected and the 3-hydroxybenzo[ a ]pyrene (3-OHB a P) and 1-hydroxypyrene (1-OHPy) analyzed according to procedures using automated column-switching high-performance liquid chromatography. The exposure profiles indicate an important lag between the excretion of the two metabolites: the maximum of 3-OHB a P urinary excretion is observed 10 to 17 hr after the 1-OHPy maximum, with a much closer correlation ( r = 0.81) than that obtained with both metabolites in real time ( r = 0.21). This delayed excretion agrees with data from animal intoxication studies (intravenous administration or inhalation). Mean ratios of 1-OHPy to 3-OHB a P were studied without lag (varying from 2,230 to 15,330) and with a lag of 16 hr (varying from 940 to 8,390).     

The Use of Spectrofluorimetry for Monitoring the Bioaccumulation and the Biotransformation of Polycyclic Aromatic Hydrocarbons in Daphnia magna

A rapid and direct spectrofluorimetric method was tested in order to monitor the bioaccumulation of PAHs in Daphnia magna in a control media. After exposure to water containing benzo[ a ]pyrene or fluoranthene, daphnids were put in solvent, sonicated, and filtered. The fluorescence spectrum observed in the filtrate was recorded. Results were compared to HPLC measurements of the same pools of organisms. In fluoranthene experiments, the fluorescence peak of the daphnid extract spectrum was linearly related to the PAH content as measured with HPLC. In benzo[ a ]pyrene experiments, other fluorescent compounds progressively appeared in the sample. They were assumed to be metabolites. A linear regression involving fluorescence intensities at two different wavelengths was necessary for a satisfactory correlation with HPLC measurements. A water extraction was performed to isolate metabolites. None or very few fluoranthene metabolites were isolated in the aqueous phase, whereas increasing benzo[ a ]pyrene metabolites were observed while the exposure time increased.     

Activation of Polycyclic Aromatic Compounds by cDNA-Expressed Phase I and Phase II Enzymes

A large number of human and other mammalian xenobiotic-metabolizing enzymes have been expressed in target cells of standard mutagenicity tests, such as Ames's Salmonella typhimurium strains and Chinese hamster V79 cells. These recombinant cells are useful for determining the ability of individual enzymes to activate (or inactivate) a given compound. In contrast to standard S9-mediated test systems, they also allow the detection of mutagenic metabolites that do not penetrate cell membranes--a situation often found with reactive phase II metabolites. We present mutagenicity data for benzo[ a ]pyrene and dibenzo[ a,l ]pyrene in V79-derived cells expressing human cytochrome P450 (CYP) 1A1, 1A2, and 1B1, and for 1-hydroxymethylpyrene, R - and S -1-( f -hydroxyethyl) pyrene, 4-hydroxycyclopenta[ def ]chrysene and N -hydroxy-2-acetylaminofluorene in V79-derived cells and/or Salmonella strains expressing the 11 human sulfotransferases (SULTs) identified. In some cases, allelic variants and orthologous enzymes from other mammalian species were also investigated. The data indicate that mutagenicity of many compounds is detected in the appropriate recombinant systems at extremely low substrate concentrations, that the activation of various promutagens is mediated with high specificity by only one or few enzyme forms, and that substantial differences may occur between alloenzymes from the same species and orthologous enzymes from different species. Such information could be important for understanding differences in susceptibility between tissues, species, individual genetic traits, and physiological states.     

Polycyclic Aromatic Hydrocarbons in Maternal and Cord Blood Plasma

Abstract

Polycyclic aromatic hydrocarbons (PAH) come from incomplete combustion of organic materials, including tobacco smoke. Some PAH are known to be mutagenic and carcinogenic and of concern for the fetus when women smoke during pregnancy. Known consequences of smoking during pregnancy include low birth weight (LBW) and preterm (PT) delivery. This study was designed to measure concentrations of 3 PAH: anthracene (A), benzo(a)pyrene (BP) and 1-hydroxypyrene (1-HP) in paired maternal (M) and cord blood (CB) samples. Additionally, we explored relationships between the PAH concentrations and LBW or PTD. Cotinine was used as a biomarker of tobacco exposure. All 3 PAH were found in M and CB plasma. A was significantly elevated in CB plasma compared to M plasma at higher M cotinine concentrations. BP in PT infants was significantly lower than in term. There were significant correlations between M and CB concentrations of anthracene. Correlations of 1-HP with cotinine in CB and M plasma were significant but opposite in direction. Anthracene, benzo(a)pyrene and 1-hydroxypyrene are present in measurable concentrations in M and CB plasma at the time of delivery. The higher concentrations of anthracene in CB plasma may be due to differences in maternal metabolism during pregnancy, length of labor or metabolism in the fetus. Long-term effects of anthracene on the infant are unknown and merit further investigation.     

高效液相色谱法检测植物油中苯并[a]芘的含量

建立并验证高效液相色谱法检测植物油中苯并[a]芘的含量.将植物油样品溶于正己烷中混匀,用苯并[a]芘固相萃取柱净化,用正己烷洗脱苯并[a]芘,荧光检测器检测.苯并[a]芘在0.1～100μg/kg浓度范围内线性相关系数r2=0.9999,本方法平均回收率为96.95%～101.30%,相对标准偏差RsD为0.980%～...     

NMR Solution Structures of Adducts Derived from the Binding of Polycyclic Aromatic Diol Epoxides to DNA

Site-specifically modified oligonucleotides were derived from the reactions of stereoisomeric polycyclic aromatic diol epoxide metabolite model compounds with oligonucleotides of defined base composition and sequence. The NMR solution structures of ten different adducts studied so far are briefly described, and it is shown that stereochemical factors and the nature of the oligonucleotide context of the complementary strands, exert a powerful influence on the conformational features of these adducts.     

Photooxidation of Polycyclic Aromatic Hydrocarbons over NaBiO3 under Visible Light Irradiation

The NaBiO₃ samples (NaBiO₃ · nH₂O) used in photooxidation of polycyclic aromatic hydrocarbon were obtained through heating NaBiO₃ · 2H₂O. The samples were characterized by X-ray diffractometer and ultraviolet-visible spectrophotometer. The photooxidation of anthracene and Benz[a]anthracene over NaBiO₃ · nH₂O was investigated, respectively. The intermediates were analysed by gas chromatography-mass spectrometer. The results indicated that the prepared NaBiO₃ samples showed considerable photooxidation activity and stability for PAHs degradation under visible light irradiation. The possible reaction pathways of the decomposition of the two polycyclic aromatic hydrocarbons were proposed. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Preparation of Test Material and Evaluation of a Proficiency Test for Official Food Control Laboratories on the Determination of Polycyclic Aromatic Hydrocarbons in Baby Food

A proficiency test on the determination of polycyclic aromatic hydrocarbons (PAHs) was organized by the German National Reference Laboratory for PAH in 2010. The test samples were produced by spiking cereal-based instant baby food with PAHs at concentration levels between 0.6 and 3.8 μg/kg; homogeneity and stability of the test material were verified before sample dispatch. Twenty-one official laboratories from Germany and Austria participated in the test and the evaluation of the test was done by applying methods of robust statistics. The individual performance was assessed with the help of z-scores. As to the quantitative results, the dispersion of data for the most important group of benzo(a)pyrene (BaP), benz(a)anthracene (BaA), benzo(b)fluoranthene (BbF), and chrysene (CHR) appeared to be acceptable, with a relative robust standard deviation ranging from 13.2% for BbF to 26.7% for BaA. In total, the performance of one laboratory had to be rated as unsatisfactory because of a result for BaP outside the limits of tolerance. The methods applied in the test may be considered to be comparable, as no significant effects in the distribution of data could be attributed to certain analytical procedures.