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The ex situ study of vermiextraction of Acenaphthylene (AcPY), Benzo(e)pyrene (BeP) and Benzo(ghi)perylene (BP) form constructed vermiculture containing petroleum contaminated soil (8.00±0.01, 9.80±0.00 and 5.02±0.00 mg/kg respectively) and vermiaccumulation (AcPY, 1.05±0.00, BeP, 2.01±0.00 and BP, 1.73±0.00 mg/kg) by Esenia fetida squirms with mean vermiremoval efficiency of 100% while vermiconversions were AcPY, 86.88, BeP, 79.49 and BP, 65.54%. The identification and quantification of the 3 polycyclic aromatic hydrocarbons (3PAHs) were performed by GS/MD in accordance with analytical procedure of US. EPA 8270; 625. The bioengineered approach by E. fetida squirms in the vermiculture proved effective to detoxify and remove the persistent organic pollutants of the 3PAHs. The ex situ study of vermiextraction of Acenaphthylene (AcPY), Benzo(e)pyrene (BeP) and Benzo(ghi)perylene (BP) form constructed vermiculture containing petroleum contaminated soil (8.00±0.01, 9.80±0.00 and 5.02±0.00 mg/kg respectively) and vermiaccumulation (AcPY, 1.05±0.00, BeP, 2.01±0.00 and BP, 1.73±0.00 mg/kg) by Esenia fetida squirms with mean vermiremoval efficiency of 100% while vermiconversions were AcPY, 86.88, BeP, 79.49 and BP, 65.54%. The identification and quantification of the 3 polycyclic aromatic hydrocarbons (3PAHs) were performed by GS/MD in accordance with analytical procedure of US. EPA 8270; 625. The bioengineered approach by E. fetida squirms in the vermiculture proved effective to detoxify and remove the persistent organic pollutants of the 3PAHs.

In this study, we investigated the anti-oxidant, anti-inflammatory, whitening, anti-wrinkle, and anti-pollution effects of Neem tree (i.e., Azadirachta indica leaf) 70% ethanol extract. More specifically, the polyphenol content was 51.37 mg/g, and the DPPH and ABTS radical scavenging activities were 34.09 and 72.18%, respectively, at a final concentration of 1,000 μg/mL. SOD experiments showed an effect of 24.13% at a final concentration of 1,000 μg/mL. In addition, to investigate the whitening effect, the tyrosinase inhibition effect was measured, giving a value of 47.21% at a final concentration of 1,000 μg/mL. Furthermore, MTT assay experiments were carried out on macrophages (RAW 264.7) to determine the cytotoxicity using the neem tree leaf extract, it was confirmed that the cell viability was unaffected up to a concentration of 100 μg/mL. Moreover, anti-inflammatory (NO) analysis of the cells using macrophages stimulated with LPS induced an inflammatory response of 68.86%, in addition to an anti-inflammatory activity of 66.45% at a final concentration of 100 μg/mL. The iNOS protein showed an inhibition rate of 97.49% at a concentration of 100 μg/mL, and in the cytotoxicity assay (MTT assay) using keratinocytes (HaCaT), the cell viability was similar to that of the untreated control at 10 μg/mL. Western blotting analysis confirmed the inhibition rate of MMP-1. Additionally, HaCaT and CCD-986sk human skin cells were stimulated with benzo[e]pyrene, which contains fine dust and heavy metals, and then treated with neem tree extract to measure the effect of the extract on the cell viability. Indeed, the anti-pollution efficacy of the extract was confirmed. Overall, the benzo[e]pyrene-stimulated cells presented improvements of >92 and 81% for the HaCaT and CCD cells at a concentration of 25 μg/mL, while improvements were observed at a concentration of 100 μg/mL HaCaT for fine dust-stimulated cells. Moreover, HaCaT cell and CCD cells showed improvements of more than 85 and 76%, respectively. The obtained results therefore indicate that Neem tree 70% ethanol extract is expected to have value for application in cosmetics due to its pharmacological activity and its fine dust-blocking properties.

PurposeThe aim of this study was to examine the effect of 17β-estradiol on Benzo(e)pyrene [B(e)P]-induced toxicity in ARPE-19 cells.MethodsWe pretreated ARPE-19 cells with 20 nM and 40 nM 17β-estradiol for 6 hours, followed by addition of 300 μM B(e)P for additional 24 hours. Cell viability was measured using Trypan blue dye-exclusion assay. JC-1 assay was performed to measure mitochondrial membrane potential (ΔΨm). For a quantitative estimation of cell death, apoptotic markers such as caspase-3/7, caspase-9, and caspase-12 were measured.ResultsOur results demonstrated that when treated with B(e)P, the viability and ΔΨm of ARPE-19 cells declined by 25% and 63%, respectively (P < 0.05). However, pretreating with 17β-estradiol increased the viability of ARPE-19 cells by 21% (20 nM) and 10% (40 nM) (P < 0.05). Furthermore, the significantly reduced ΔΨm in βE+B(e)P treated cells ARPE-19 cells was restored by pre-treatment with 17β-estradiol- ΔΨm was increased by 177% (20 nM) and 158% (40 nM) (P < 0.05). We further observed a significant up-regulation in the activity of Caspases-3/7, -9, and -12 in B(e)P-treated ARPE-19 cells. However, 17β-estradiol treatment significantly reduced the activity of all apoptotic markers (P < 0.05).ConclusionIn conclusion, our results demonstrate that 17β-estradiol protects ARPE-19 cells against B(e)P-induced toxicity by decreasing apoptosis, preventing cell death, and restoring mitochondrial membrane potential.

Author(s): Estrago-Franco, M Fernanda; Moustafa, M Tarek; Riazi-Esfahani, Mohammad; Sapkal, Ashish U; Piche-Lopez, Rhina; Patil, A Jayaprakash; Sharma, Ashish; Falatoonzadeh, Payam; Chwa, Marilyn; Luczy-Bachman, Georgia; Kuppermann, Baruch D; Kenney, M Cristina | Abstract: PurposeTo identify inhibitors that could effectively lower reactive oxygen/nitrogen species (ROS/RNS), complement and inflammatory cytokine levels induced by Benzo(e)pyrene [B(e)p], an element of cigarette smoke, in human retinal pigment epithelial cells (ARPE-19) in vitro.MethodsARPE-19 cells were treated for 24 hours with 200 μM, 100 μM, and 50 μM B(e)p or DMSO (dimethyl sulfoxide)-equivalent concentrations. Some cultures were pre-treated with ROS/RNS inhibitors (NG nitro-L-arginine, inhibits nitric oxide synthase; Apocynin, inhibits NADPH oxidase; Rotenone, inhibits mitochondrial complex I; Antimycin A, inhibits mitochondria complex III) and ROS/RNS levels were measured with a fluorescent H2 DCFDA assay. Multiplex bead arrays were used to measure levels of Interleukin-6 (IL-6), Interleukin-8 (IL-8), Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF), Transforming Growth Factor alpha (TGF-α) and Vascular Endothelial Growth Factor (VEGF). IL-6 levels were also measured by an enzyme-linked immunosorbent assay. Real-time qPCR analyses were performed with primers for C3 (component 3), CFH (inhibits complement activation), CD59 (inhibitor of the complement membrane attack complex (MAC)) and CD55/DAF (accelerates decay of target complement target proteins).ResultsThe ARPE-19 cultures treated with B(e)p showed significantly increased ROS/RNS levels (P l 0.001), which were then partially reversed by 6 μM Antimycin A (19%, P = 0.03), but not affected by the other ROS/RNS inhibitors. The B(e)p treated cultures demonstrated increased levels of IL-6 (33%; P = 0.016) and GM-CSF (29%; P = 0.0001) compared to DMSO-equivalent controls, while the expression levels for components of the complement pathway (C3, CFH, CD59 and CD55/DAF) were not changed.ConclusionThe cytotoxic effects of B(e)p include elevated ROS/RNS levels along with pro-inflammatory IL-6 and GM-CSF proteins. Blocking the Qi site of cytochrome c reductase (complex III) with Antimycin A led to partial reduction in B(e)p induced ROS production. Our findings suggest that inhibitors for multiple pathways would be necessary to protect the retinal cells from B(e)p induced toxicity.

We report zero kinetic energy (ZEKE) photoelectron spectroscopy via resonantly enhanced multiphoton ionization (REMPI) for benzo[ e ]pyrene. Extensive vibronic coupling between the first electronically excited state and a nearby state allows b 2 modes to be observed which would be Franck–Condon (FC) disallowed. These vibronic modes are comparable in intensity to the FC allowed a 1 modes. We are able to qualitatively simulate the vibronic spectra of both REMPI and ZEKE using density functional methods. The ZEKE spectra demonstrate propensity in preserving the vibrational excitation of the intermediate state. These results suggest a remarkable structural stability of B e P in accommodating the additional charge.

The donor-acceptor-donor (D-A-D) conjugated molecules 1,4-bis(diarylaminophenylethynyl)anthraquinone (1,4-Am(2)Aq) and 1,4-bis(ferrocenylethynyl)anthraquinone (1,4-Fc(2)Aq), undergo a double proton cyclization reaction with bis(trifluoromethanesulfone)imide acid (TFSIH) to yield 1,4-bis(diarylaminophenyl or ferrocenyl) dipyrylium salts [1,4-R(2)Pyl(2)](TFSI)(2) (R=Am or Fc) with novel planar pentacyclic structures similar to the aromatic benzo[e]pyrene-type skeleton. [1,4-Am(2)Pyl(2)](TFSI)(2) could be reduced to give the neutral molecule [1,4-Am(2)Pyl(2)](0), which is stable and maintains the benzo[e]pyrene-type skeleton. To the best of our knowledge, this is the first oxygen-atom-containing polycyclic aromatic hydrocarbon with 22 (4n+2) π-electrons. The obtained condensed-ring benzo[e]pyrene-type skeleton compounds show physical and chemical properties that are significantly different from those of [1,5-Am(2)Pyl(2)](TFSI)(2), which has a perylene-type skeleton.

Absorption and fluorescence emission spectra of the polycyclic aromatic hydrocarbons benzo[a]pyrene (BaP) and benzo[e]pyrene (BeP) in solution and adsorbed on silica have been obtained and compared to examine the spectroscopic effects of clustering. Molecular mechanics calculations with the UFF potential were done to optimize monomer, dimer and trimer geometries, and energy differences were determined by MP2/6-31G* calculations. Fluorescence emission spectra of adsorbed BeP and BaP display a red shift that progresses with increased loading, and the two differ in their photodegradation kinetics. The experimental and theoretical results are found to be consistent.

New solid-matrix phosphorescence (SMP) methods for (±)- anti -DB[ a , l ]PDE-DNA adducts and B[ e ]P were developed. The methods can be used to detect and characterize (±)- anti -DB[ a , l ]PDE-DNA adducts and B[ e ]P by employing SMP spectra, intensities, and lifetimes acquired with the heavy-atom salt, TlNO 3 , on Whatman 1PS paper. With the SMP data, a number of photophysical parameters were calculated such as biexponential SMP decay curves, pre-exponential factors, and fractional contribution to SMP decay curves. The SMP results were compared with earlier SMP data for (±)- anti -BPDE-DNA adducts and tetrol I-1. The SMP results show that small molecular-weight compounds like B[ e ]P can be readily detected and characterized by SMP. For example, the limit of detection for B[ e ]P was 0.60 pmol. Comparison of the SMP properties of the (±)- anti -DB[ a , l ]PDE-DNA adducts with earlier SMP data for the (±)- anti -BPDE-DNA adducts showed major differences in the SMP spectra, intensities, and lifetimes. The methods developed are important for the comparison of the SMP properties of different diol epoxides of PAH bonded to DNA.

[structure: see text] The synthesis of phenanthrene and benzo[e]pyrene bisimides, 1 and 2, was accomplished via the Diels-Alder trapping of sterically congested o-xylylenols photochemically generated from 3,6-dibenzoyl-o-xylene and 1,4-dibenzoyl-9,10-dihydroanthracene, respectively. Absorption and emission from 2 are red-shifted from 1 and unsubstituted benzo[e]pyrene. The fluorescence quantum yield for 2 is an order of magnitude lower than that of 1 and comparable to that of the parent benzo[e]pyrene.

The solid-matrix fluorescence (SMF) quenching of benzo[e]pyrene and (±)-anti-dibenzo[a,l]pyrene-11,12-diol-13,14-epoxide ((±)-anti-DB[a,l]PDE)-DNA adducts with thallium nitrate (TlNO3) and sodium iodide (NaI) was examined and several SMF quenching models were developed. The SMF quenching data for B[e]P with either TlNO3 or NaI fit a two-independent-binding-site model. However, the SMF quenching of (±)-anti-DB[a,l]PDE-DNA adducts with TlNO3 fits a sphere of action model, but quenching with NaI was modeled with the two-independent-binding-site model. The data were compared with earlier SMF quenching data for 7,8,9,10-tetrahydroxytetrahydro-benzo[a]pyrene (tetrol I-1) and (±)-anti-benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide ((±)-anti-BPDE)-DNA adducts. The interpretation of the SMF quenching data for the (±)-anti-DB[a,l]PDE-DNA adducts was distinctively different than the interpretation of the SMF quenching data for the (±)-anti-BPDE-DNA adducts. This initial study shows that SMF quenching has the potential to characterize polycyclic aromatic hydrocarbon-DNA adducts with different numbers of aromatic rings. In addition, the data indicated that external and intercalated DNA adducts interacted with heavy-atom salts in dissimilar fashions. The new SMF methodology developed is useful for the characterization of both polycyclic aromatic hydrocarbon-DNA adducts and metabolites from polycyclic aromatic hydrocarbons.

A new and simple method has been developed for determining high molecular mass polycyclic aromatic hydrocarbons (PAHs) in refined olive pomace, and other vegetable oils from an initial sample of 0.25 g. The hydrocarbon fraction is isolated by solid-phase extraction (SPE) on silica gel using hexane as eluent. The fraction is evaporated to reduced volume and cleaned-up by SPE on an amino phase eluting with toluene. The evaporated residue, dissolved in acetonitrile, is analyzed by reverse-phase high-performance liquid chromatography with fluorescence detector using programmed excitation and emission wavelengths. The benzo(e)pyrene is determined together with other usual heavy PAHs. Interferences due to squalene and other hydrocarbons are minimized. Recoveries were greater than 80% and detection limits ranged from 0.01 to 0.2 µg kg−1. The method was validated using certified oil samples and was applied to various vegetable oils. Copyright © 2004 Society of Chemical Industry

Benzo[e]pyrene (BeP) is a widespread polycyclic aromatic hydrocarbon found principally in highly polluted areas. The study of its photochemistry is important because of its possible toxic nature and its potential for phototransformation into biologically active products. We studied the primary photophysical and photochemical degradation processes of BeP, both in solution and adsorbed on silica gel and alumina, acting as models for the atmospheric particulate matter. The radical cation of BeP was characterized as an intermediate species during the photodegradation of BeP in polar solvents and adsorbed on the surfaces. The photoionization process was monophotonic, and once the radical cation was formed, it could react with water or oxygen to yield mainly diones, alcohols, and diols. In alumina, the radical yield was small, in accordance with the low photoreactivity observed on this surface. Two triplet−triplet absorption bands at 350 and 560 nm were observed in the time-resolved spectra of adsorbed BeP and ...

The photodegradation of several polycyclic aromatic hydrocarbons (PAHs) including phenanthrene, benzo(a)pyrene, and benzo(e)pyrene was studied under different estuarine conditions to elucidate the effects of dissolved organic matter (DOM), salinity, and suspended particles on PAH photodegradation in the estuarine surface water. Besides the competitive light absorption effect, DOM can accelerate the photodegradation of small PAHs such as phenanthrene by enhancing the formation of reactive intermediates and inhibit the photodegradation of large PAHs such as benzo[a]pyrene (BaP) and benzo[e]pyrene (BeP) by binding the PAH molecules. High salinity would accelerate the photodegradation of PAHs; however, the magnitude and direction of the salt effect are complicated in the presence of DOM due to the "salting-out" effect on the binding of PAHs with DOM. Suspended particulate matter in the estuary provides an alternative solid-phase photodegradation pathway for PAHs, which proceeds faster than the aqueous phase. Particulates apparently exert different effects on the photodegradation of phenanthrene (Phe) and BaP as a result of the combined effects of light absorption, particulate organic matter, PAH surface sorption, and concentration dilution in the presence of suspended particulate matter.

The objective of this study is to clarify the effect of photooxidation on δ13C of benzo(a)pyrene (BaP) and benzo(e)pyrene (BeP) in the atmosphere. They are structural isomers but are known to differ significantly in terms of photooxidation rate. The results of literature reviews and measurements revealed that the concentration ratio of BaP and BeP (BaP/BeP) is almost constant independent of the fuel type and emission source (almost constant at 2.1), while δ13C values for the two PAHs are almost equal. On the other hand, the results of ultraviolet irradiation experiments indicated that the concentration of BaP was reduced by photooxidation while δ13C of the remaining BaP increased due to isotopic fractionation. In contrast, BeP was not photooxidized and there was no change in δ13C. These results lead to the expectation that BaP/BeP and the difference in δ13C between BaP and BeP (δ13CBaP – δ13CBeP) would decrease and increase, respectively, from the corresponding values at the time of emissions (BaP/BeP: ∼2.1; δ13CBaP – δ13CBeP: ∼0) with the progress of photooxidation. This anticipated relationship was close to the results observed over Matsue, which is located on the Japan Sea coast, strongly suggesting there is a change in δ13C of BaP due to photooxidation. In addition, the observed results revealed that BaP/BeP and δ13CBaP – δ13CBeP levels during the winter, when photooxidation is less likely to occur compared to the summer, were similar to the levels during the summer. This supports the hypothesis that in winter, BaP emitted in the Asian continent was photooxidized during the long-range transport process before reaching the atmosphere over Matsue.

NRH:quinone reductase (QR2) is present in the retinas of embryonic and post-hatched (PH) chicks. 5-Methoxycarbonylamino-N-acetyltryptamine (5-MCA-NAT) is a QR2 ligand that increases cAMP levels in developing retinas, but it does not affect cAMP levels in CHO-QR2 cells. The dopamine quinone reductase activity of QR2 retrieves dopamine, which increases cAMP levels in developing retinas. The objective of the present study was to investigate whether 5-MCA-NAT increases endogenous dopamine levels in retinas from chick embryos and post-hatched chicks. Endogenous dopamine was measured by enzyme-linked immunosorbent assay (ELISA). 5-MCA-NAT increased retinal endogenous dopamine levels at all developmental stages studied and in PH chicks (-logEC50=11.62±0.34 M). This effect was inhibited by non-selective antagonists of receptors and melatonin binding sites N-acetyl-2-benzyltryptamine (luzindole, 5 μM), but it was not inhibited by the Mel1b melatonin receptor antagonist 4-phenyl-2-propionamidotetralin (4-P-PDOT, 10 nM). The QR2 cosubstrate, N-methyl-dihydronicotinamide (NMH) (-logEC50=6.74±0.26 M), increased endogenous dopamine levels in controls and in retinas stimulated with 5-MCA-NAT (3 nM). The QR2 inhibitor benzo[e]pyrene inhibited endogenous dopamine levels in both control (-logIC50=7.4±0.28 M) and NMH-stimulated (at 100 nM and 1 μM benzo[e]pyrene concentrations) retinas. Theoretical studies using Molegro Virtual Docking software corroborated these experimental results. We conclude that 5-MCA-NAT increases the level of endogenous dopamine via QR2. We suggest that this enzyme triggers double reduction of the dopamine quinone, recovering dopamine in retinal development.

In the mechanistic study of the oxygenation of polycyclic aromatic hydrocarbons (PAHs) by mixed-function oxidase, we employed hemoglobin (Hb) as a model compound for cytochrome P450. We found that the relative intensities of several Raman peaks of benzo(a)pyrene (BaP) and benzo(e)pyrene (BeP) in the region between 600 and 1600 cm−1 are significantly enhanced by the oxygenated Hb but not by the deoxygenated Hb. This seems to indicate that these affected vibrations could be the modes involved in PAH epoxidation by the heme-bound oxygen. Density functional theoretical calculations were carried out using a commercially available software package. The DN** basis set appears to give the most satisfactory results. The difference in wave numbers between observed and calculated wave numbers is estimated to be

Benzo[e]pyrene (BeP) is a polycyclic aromatic hydrocarbon with teratogenic and possibly mutagenic activities. The study of its phototransformations in the atmosphere is of relevance because some of the photoproducts could be of higher toxicity. Photochemical studies of BeP adsorbed on non-activated silica gel and alumina, selected as models of the atmospheric particulate, were made. The effect of the pore size of the surface, coadsorbed gases (O2 and Ar) and water on the spectroscopic properties and the photodegradation rates of BeP have been studied by fluorescence, diffuse reflectance and EPR techniques. The interaction between the PAH and the surface of the silica gel is affected by the average pore size. Band broadening is observed when water is coadsorbed with BeP. Oxygen quenches significantly the excited singlet state and affects its photodestruction. The formation of new emission and absorption bands is observed when the photolysis is carried out in the presence of oxygen. Under Ar atmosp...

Photoelectron spectra of benzo[a]pyrene and benzo[e]pyrene have been assigned on the basis of ab initio electron propagator theory. Electron correlation effects are included in the partial third order approximation and agreement with experimental peaks is very close. To each ionization energy, there corresponds a Feynman–Dyson amplitude that exhibits the change in electronic structure associated with the removal of an electron. Correlation corrections to the Koopmans description of the cationic states are large for many states, but the qualitative validity of this model remains valid. The lowest final states with σ holes occur around 11.0 eV.

Benzo(a)pyrene (BaP) belongs to a class of polycyclic aromatic hydrocarbon and is reported as a potent human carcinogen. We performed a nanoLC-MS/MS-based label-free quantitative proteomics approach to identify potential biomarkers of exposure in the secretome of BaPtreated vs. non-treated and Benzo(e)pyrene (BeP)-treated human hepatoma cell line HepG2.BeP-treated cells were chosen as a negative control to distinguish the BaP-specific from the HAP-specific regulated proteins: BeP is not classifiable as to its carcinogenicity to humans. 847 proteins have been identified and quantified and 55 proteins were seen as being highly upregulated with a fold change of at least 5. Most of these up-regulated proteins were focused incancer-related activities. Further validation of expression of these proteins in the plasma of BaP-exposed population will assist in the development of biomarkers that will greatly improve early detection, prognosis, prediction of treatment response and prevention.; Le Benzo(a)pyrène (BaP), appartenant à la famille des hydrocarbures aromatiques polycycliques (HAP) est cancérigène pour l’homme. Nous avons développé une approche protéomique quantitative nanoLC-MS/MS label-free pour identifier des biomarqueurs liés à l’exposition au BaP dans le sécrétome des cellules hépatiques humaines exposées au BaP vs. des cellules non exposées et exposées au Benzo(e)pyrène (BeP). Le BeP, agent non classifié comme cancérigène pour l’homme, est choisi comme contrôle négatif afin de distinguer les protéines spécifiques du BaP de celles des HAP. 847 protéines ont été identifiées et quantifiées, et 55 ont été fortement surexprimées avec un ratio supérieur à 5 : la plupart de ces protéinessurexprimées sont précoces et liées au cancer. Une validation ultérieure de l'expression de ces protéines dans le plasma de la population exposée au BaP aidera dans le développement de biomarqueurs qui permettront d'améliorer la détection précoce, le pronostic et prévention.

Benzo[e]pyrene is a pentacyclic aromatic hydrocarbon, which, unlike its structural isomer benzo[a]pyrene, is not a potent carcinogen or mutagen. The metabolism of benzo[e]pyrene was studied using the filamentous fungus Cunninghamella elegans ATCC 36112. C. elegans metabolized 65% of the [9, 10, 11, 12-3H]benzo[e]pyrene and unlabeled benzo[e]pyrene added to Sabouraud dextrose broth cultures after 120 h of incubation. Three major metabolites of benzo[e]pyrene were separated by reversed-phase high-performance liquid chromatography. These metabolites were identified by 1H and 13C NMR, UV-visible, and mass spectral analyses as 3-benzo[e]pyrenylsulfate, 10-hydroxy-3-benzo[e]pyrenyl sulfate, and benzo[e]pyrene 3-O-β-glucopyranoside.

A flow-through/first derivative synchronous spectrofluorimetric sensor for the determination of PAH has been described. This sensor has been used for the simultaneous determination of PAH mixtures (pyrene, benzo(e)pyrene and benzo(ghi)perylene). Linear calibration ranges between 10 and 500 ng/ml with acceptable precision (repeatability, expressed as relative standard deviation, smaller than 4.6%, and sampling frequency of 12 h(-1)) have been obtained. The method has been applied to the determination of the target analytes in spiked water samples with excellent results (recoveries between 94 and 108%).

Metabolites of benzo(e)pyrene (B[e]P) formed upon incubation of [3H]-B[e]P with hepatic microsomes from control and induced rats have been separated by high-pressure liquid chromatography and identified by comparison of retention times, absorbance and fluorescence spectra with those of synthetic standards. The major metabolite produced was B[e]P-4,5-dihydrodiol, accounting for 20-30% of the total metabolism depending on the source of the microsomes. This was followed by a phenolic metabolite (shown not to be 4-OH-; 9-OH-; or 10-OH-B[e]P). A possible proximate carcinogenic derivative of B[e]P, B[e]P-9,10-dihydrodiol, was identified, but was found to constitute less than 1% of the total metabolites. Similar results were obtained with a purified and reconstituted mixed-function oxidase system. In these later incubations, production of the dihydrodiols was dependent on the addition of purified epoxide hydrase to the incubation mixtures. These results suggest that formation of the reactive diol-epoxide, 9,10-dihydroxy-11,12-epoxy-9,10,11,-12-tetrahydro-B[e]P, a potential ultimate carcinogenic metabolite of B[e]P, is not favored by rat liver enzymes. This provides a partial explanation for the lack of carcinogenicity of B[e]P within the framework of the bay region theory of chemical carcinogenesis.

Hepa 1c1c7 (WT), TAOc1BPrc1 (CI), and BPrc1 (CII) mouse hepatoma cells were exposed to benzo[e]pyrene (B[e]P) or benzo[a]pyrene (B[a]P). B[e]P induced activity of a rat CYP1A1 reporter gene construct (-3015 to +2545 bp) by 1.8- to 2-fold and 5-fold in WT and CI cells, respectively. B[e]P caused a 2-fold induction of a truncated CYP1A1 reporter gene construct (-658 to +2545 bp) in WT cells and induced ethoxyresorufin O-deethylase (EROD) activity by 24- and 13-fold in WT and CI cells. B[a]P also induced CYP1A1 reporter gene and EROD activity in these cells. WT and CII cells had both 8S (Ah) receptor and 4S polycyclic hydrocarbon (PAH)-binding activity, while CI cells exhibited a lower 4S binding activity; 8S binding activity was not detected in CI cells under two separate binding conditions. 8S binding activity in the presence of sodium molybdate was 60-fold greater in WT cells than in CII cells. The absence of sodium molybdate resulted in a dramatic decrease of 8S binding activity in WT cells. The ability of B[e]P to induce CYP1A1 promoter-reporter gene activity and EROD activity in WT and CI cells suggested a role for the 4S PAH-binding protein in the induction of CYP1A1. The lack of detectable 8S binding activity in CI cells was in concert with this role.

Naphtho[1,2,3-mno]acephenanthrylene, a cyclopenta-fused derivative of benzo[e]pyrene more mutagenic than benzo[e]pyrene in the Salmonella typhimurium plate incorporation assay, was shown to be metabolized by Aroclor 1254-treated rat liver S9 principally to the cyclopenta dihydrodiol, trans 3,4-dihydroxy-3,4-dihydronaphtho[1,2,3-mno]acephenanthrene. Since the metabolic profile indicated that the cyclopenta epoxide was quantitatively the major intermediate formed, this epoxide was synthesized, by oxidation of the parent hydrocarbon with dimethyldioxirane. Direct-acting mutagenic potency was about 200 revertants per nanomol in strain TA98, approximately five times that previously reported for the parent hydrocarbon. The activity of the epoxide was decreased, but not entirely abolished, in the presence of S9. Epoxidation at the cyclopenta-fused ring can therefore account for much of the genotoxicity of naphtho[1,2,3-mno]acephenanthrylene in the Salmonella typhimurium plate incorporation assay system.

The present studies were undertaken to provide a rationale for the observation that benzo( a )pyrene and 2-acetylaminofluorene induce the hepatic CYP1 A1 protein, whereas their non-carcinogenic isomers benzo( e )pyrene and 4-acetylaminofluorene are, at best, relatively very weak inducers. Using amino acid sequence alignment, a molecular model of the CYP1A1 was constructed by analogy to CYP101, the bacterial protein for which the 3-dimensional structure is known from X-ray crystallographic analysis. The putative structure of the active site of the CYP1A1 protein shows the presence of two phenylalanine residues preferentially aligned in parallel orientation, presumably functioning as a ‘sieve’ for planar molecules, the established substrates of CYP1A1. The molecular dimensions of this putative access channel show a width and depth of 8.321 and 3.261 A, respectively. The width of 4-acetylaminofluorene, 8.794 A, and benzo( e )pyrene, 9.153 A, precludes their passage through this channel access in contrast to benzo( a )pyrene and 2-acetylaminofluorene having a width of 7.150 and 5.283 A, respectively, explaining their difference in CYP1A1 induction potential.

This study assessed the role of aryl hydrocarbon receptor (AHR) affinity, and cytochrome P4501A (CYP1A) protein and activity in polyaromatic hydrocarbon (PAH)-induced oxidative stress. In the 1–100 nM concentration range benzo[a]pyrene (BaP) but not benzo[e]pyrene (BeP) competitively displaced 2 nM [3H]2, 3, 7, 8-tetrachloro-dibenzo-p-dioxin from rainbow trout AHR2α. Based on appearance of fluorescent aromatic compounds in bile over 3, 7, 14, 28 or 50 days of feeding 3 μg of BaP or BeP/g fish/day, rainbow trout liver readily excreted these polyaromatic hydrocarbons (PAHs) and their metabolites at near steady state rates. CYP1A proteins catalyzed more than 98% of ethoxyresorufin-O-deethylase (EROD) activity in rainbow trout hepatic microsomes. EROD activity of hepatic microsomes initially increased and then decreased to control activities after 50 days of feeding both PAHs. Immunohistochemistry of liver confirmed CYP1A protein increased in fish fed both PAHs after 3 days and remained elevated for up to 28 days. Neither BaP nor BeP increased hepatic DNA adduct concentrations at any time up to 50 days of feeding these PAHs. Comet assays of blood cells demonstrated marked DNA damage after 14 days of feeding both PAHs that was not significant after 50 days. There was a strong positive correlation between hepatic EROD activity and DNA damage in blood cells over time for both PAHs. Neither CYP1A protein nor 3-nitrotyrosine (a biomarker for oxidative stress) immunostaining in trunk kidney were significantly altered by BaP or BeP after 3, 7, 14, or 28 days. There was no clear association between AHR2α affinity and BaP and BeP-induced oxidative stress.

Cyclopenta-fused homologs of polycyclic aromatic hydrocarbons (PAH) have proven to be more genotoxic and tumorigenic than their parent PAHs. In an effort to uncover their mechanisms of metabolic activation, the morphological transforming activities of dibenzo[k,mno]acephenanthrylene (CP(3,4)B[a]P), dibenzo[j,mno]acephenanthrylene (CP(1,12)B[a]P) and naphtho[1,2,3,4-mno]acephenanthrylene (CPB[e]P) were studied in C3H10T12CL8 mouse embryo fibrobiasts. CP(3,4)B[a]P, a PAH with a blocked K region and unblocked bay region, was highly active inducing an average of 1,1 Type II and III foci/dish at 5 μg/ml with an average of 67% of the dishes containing foci. This activity was similar to that of benzo[a]pyrene. CP(1,12)B[a]P and CPB[e]P were inactive. The relative positions of the cyclopenta-ring and bay region may play an essential role in the metabolic activation of these PAHs and their bilogical activities.

Article discussing spectrochemical investigations of preferential solvation and fluorescence emission behavior of select polycyclic aromatic hydrocarbon solute probes dissolved in mixed solvents.

A conformational study, of the stabilities and geometries of benzo[ e ]pyrene, benzo[ e ]pyrene-9,10-oxide, benzo[ e ]pyrene-4,5-oxide, trans -9,10-dihydroxy-9,10-benzo[ e ]pyrene-9,10-oxide and trans -4,5-dihydroxy-4,5-benzo [ e ]pyrene-4,5-oxide was carried out using two semiempirical methods of quantum chemistry (MNDO and AM1). The MNDO method predicted a planar structure for the arenes and dihydrodiols except for the oxygen atom which lies outside the plane, whereas AM1 predicted a more planar conformation. Both methods predict a planar structure for benzo[ e ]pyrene.

AbstrPct: Reactions of K-region arene oxides of benz[a]anthracene (BA-0) and its 1- (1-MBA-0), 4- (CMBA-0), 7- (7-MBA-0), 11- (1 1-MBA-0), 12-methyl- (I2-MBA-O), 7,12-dimethyl-(DMBA-O), and 7-bromo- (7-BrBA-0) substituted derivatives, benzo[a] pyrene (BaP-0), benzo[c] phenanthrene (BcP-0), benzo[e] pyrene (BeP-0), benzo[g]chrysene (BgC-0), chrysene (Chr-0), dibenz[a,h]anthracene (DBA-0), phenanthrene (Phe-0), 3-bromophenanthrene (3-BrPhe-0), and pyrene (Pyr-0) with acid and methoxide ion in methanol, are compared. For the acidcatalyzed reaction, products consist of cis- and tram-methanol adducts and phenols. There is no isotope effect on the ratio of phenols to solvent adducts produced from Phe-0 or BcP-0 when deuterium is substituted for the hydrogen that migrates. This observation is consistent with a mechanism in which product distribution in acid is determined by the relative rates of solvent capture and conformational inversion of a carbocation intermediate. As expected, only trans-methanol adducts, consisting of regioisomeric mixtures for unsymmetrical arene oxides, are formed from the reaction of methoxide ion with K-region arene oxides. The use of methanol permits the identification of products formed at each benzylic position of unsymmetrical arene oxides. Rate data for reactivity at each position could be fitted to the equation log kMso/kMso- = m(1og kH/kH-) + b, where kMd and kH are the second-order rate constants of the methoxide ion addition and acid-catalyzed reaction, respectively, and kM~Phc-o and kHPbe-O are the corresponding rate constants for the reference compound phenanthrene oxide. A plot of log kMso/kMsoM vs log kH/kHPhbO for the reaction of l-MBA-O,12-MBA-O, DMBA-0, BcP-0, and BgC-0, which have either a methyl substituent in the bay region or a sterically crowded fjord region which affects the planarity of the molecules, defined one line (m = 0.31 0.02, b = 0.67 * 0.09), whereas a plot of the data for the reaction of the nearly planar arene oxides BA-O,4-MBA-O, 7-MBA-0,l I-MBA-0, BaP-0, BeP-0, Chr-0, DBA-0, Phe-0, and Pyr-0 defined a different line (m = 0.33 * 0.07,b = -0.05 * 0.05). The nonzero intercept for the sterically crowded, nonplanar arene oxides indicates a steric acceleration of their rates of methoxide ion addition. The positive slopes of both lines are consistent with an SN2 mechanism with an unsymmetrical transition state in which the epoxide C-O bond breaking is more advanced than the formation of the new C-0 bond to methoxide ion, such that a partial positive charge is developed on the aromatic moiety.

Benzo(e)pyrene (B(e)P) promotes carcinogenesis in the skin. Unlike some other promoters however, B(e)P does not produce an uncoupling effect on gap junction permeability in DM15 transformed fibroblasts. This study demonstrates that DM15 cells exhibit a relatively high level of B(e)P metabolism. Moreover, although pretreatment of DM15 cells with benz(a)anthracene results in an 8-fold increase of arylhydrocarbon hydroxylase activity and a 2-fold increase in the rate of B(e)P metabolism, it did not enable B(e)P to affect Lucifer Yellow transfer between DM15 cells. We conclude that neither B(e)P nor its metabolites are capable of uncoupling gap junction permeability in DM15 cells.

The thermodynamic stabilities of all possible arene oxides of benzo[a]pyrene and benzo[e]pyrene, and of the two parent compounds, have been obtained using semiempirical AM1 and molecular mechanics calculations. The calculations predict that all K-region epoxides are highly stabilized compared to other epoxides for both PAHs. The terminal ring epoxides include proximal and distal types, either close to or remote from the bay-region, respectively. The distal epoxides correspond to the necessary first intermediates in the enzymatic activation process leading to the ultimate bay-region dihydrodiol epoxide carcinogens. There are marked differences in the calculated heats of formation of the distal benzo[a]pyrene-7,8-epoxide and benzo[e]pyrene-9,10-epoxide (compared to either the respective parent PAHs or the K-region epoxides) favoring the epoxide from benzo[a]pyrene. One can propose that these thermodynamic differences may be a principal factor responsible for facile initiation of the activating meta...

The objective of this study was to examine the potential for a specific ligand of carcinogen binding protein (CBP) to induce changes in the overall character of hepatic microsomal cytochromes P-450 (P450) and to compare potential changes with those induced by an Ah receptor ligand. Benzo[e]pyrene (BeP) was previously shown to bind CBP with high affinity and Ah receptor with low affinity. In contrast, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) binds Ah receptor avidly and CBP weakly. Hepatic microsomes were prepared from C57BL/6J (B6) and DBA/2J (D2) mice treated with corn oil, BeP or TCDD. Relative to corn oil controls, pretreatment of B6 mice with BeP or TCDD increased the nmol P450/mg microsomal protein content 26 and 28%, respectively. In D2 mice, nmol P450/mg microsomal protein was increased 23% in the BeP pretreatment, while TCDD pretreatment had no effect relative to the corn oil controls. For the O-alkyl ethers of resorufin, rates of metabolism (per nmol P450) were affected differently in B6 and D2 by BeP pretreatment. Pentoxyresorufin O-dealkylase activity was reduced to 44% of control activity in B6 mice and increased 39% relative to controls in D2 mice. BeP pretreatment had no effect on ethoxyresorufin O-dealkylase activity in B6 mice, while this activity was decreased to 58% of controls in D2 mice. Additionally, benzyloxyresorufin O-dealkylase activity was reduced to 65% of control levels in B6 mice and not affected in D2 mice. Methoxyresorufin O-dealkylase activity was reduced in both strains to an average of 55% of control values. As expected, TCDD pretreatment resulted in increases of all O-dealkylations measured in both strains of mouse. For both inbred strains of mouse, anion exchange chromatography revealed a P450 peak associated with BeP pretreatment that was not present in chromatograms generated with corn oil or TCDD pretreatments. Results of enzyme linked immunosorbant assays also indicated that the pattern of P450 isoenzyme expression associated with BeP pretreatment was distinct from that associated with TCDD pretreatment. Overall, these data show that treatment with a specific ligand of CBP induces changes the biochemical activities and chromatographic behavior of P450 isozymes in murine hepatic microsomes. Moreover, they indicate that changes in P450 occurring after treatment with a CBP ligand are distinct from those changes that are associated with treatment with an Ah receptor ligand (TCDD). Differences between B6 and D2 strains suggest that the hepatic P450 changes occurring in response to pretreatment with a CBP ligand may be influenced by the presence of Ah receptor.

The geometries and energies of the title compounds are reported at the STO-3G and 6-31G* SCF levels, except for circumcoronene, where only the STO-3G level was employed. Group equivalents and homodesmic reactions are used to obtain heats of formation from ab initio energies. At the 6-31G* SCF level, the {Delta}H{sub f}{degrees} values for the first three compounds are similar, ranging from 66.3 to 72.2 kcal/mol. Evidence of a small additional aromatic stability for coronene is found. The ab initio enthalpy changes for homodesmic reactions containing similar structural parameters are shown to be proportional to the natural logarithm of a quantity we term the Kekule ratio: the product of reactant and product Kekule numbers, each raised to a power equal to its stoichiometric coefficient. 26 refs., 1 fig., 5 tabs.