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PubMed1983

Regio- and stereo-selective metabolism of 4-methylbenz[a]anthracene by the fungus Cunninghamella elegans.

Metabolism of 4-methylbenz[a]anthracene by the fungus Cunninghamella elegans was studied. C. elegans metabolized 4-methylbenz[a]anthracene primarily at the methyl group, this being followed by further metabolism at the 8,9- and 10,11-positions to form trans-8,9-dihydro-8,9-dihydroxy-4-hydroxymethylbenz[a]anthracene and trans-10,11-dihydro-10,11-dihydroxy-4-hydroxymethylbenz[a]anthracene. There was no detectable trans-dihydrodiol formed at the methyl-substituted double bond (3,4-positions) or at the 'K' region (5,6-positions). The metabolites were isolated by reversed-phase high-pressure liquid chromatography and characterized by the application of u.v.-visible-absorption-, 1H-n.m.r.- and mass-spectral techniques. The 4-hydroxymethylbenz[a]anthracene trans-8,9- and -10,11-dihydrodiols were optically active. Comparison of the c.d. spectra of the trans-dihydrodiols formed from 4-methylbenz[a]anthracene by C. elegans with those of the corresponding benz[a]anthracene trans-dihydrodiols formed by rat liver microsomal fraction indicated that the major enantiomers of the 4-hydroxymethylbenz[a]anthracene trans-8,9-dihydrodiol and trans- 10,11-dihydrodiol formed by C. elegans have S,S absolute stereochemistries, which are opposite to those of the predominantly 8R,9R- and 10R,11R-dihydrodiols formed by the microsomal fraction. Incubation of C. elegans with 4-methylbenz[a]anthracene under 18O2 and subsequent mass-spectral analysis of the metabolites indicated that hydroxylation of the methyl group and the formation of trans-dihydrodiols are catalysed by cytochrome P-450 mono-oxygenase and epoxide hydrolase enzyme systems. The results indicate that the fungal mono-oxygenase-epoxide hydrolase enzyme systems are highly stereo- and regio-selective in the metabolism of 4-methylbenz[a]anthracene.

Benz(a)Anthracenes↗
PubMed1977

Mutagenicity and cytotoxicity of benz[alpha]anthracene diol epoxides and tetrahydro-epoxides: exceptional activity of the bay region 1,2-epoxides.

Three diastereomeric pairs of diol epoxides, two tetrahydro-epoxides, and the K-region oxide of the polycyclic aromatic hydrocarbon benz[a]anthracene were evaluated for mutagenic activity in strain TA 100 of Salmonella typhimurium and in line V79-6 of Chinese hamster lung cells. The two diastereomeric 1,2-epoxides of the trans-3,4-dihydrodiol of benz[a]anthracene are 15 to 35 times more mutagenic to the bacteria and 65 to 125 times more mutagenic to the mammalian cells than are the diastereomeric pairs of benz[a]anthracene-8,9-diol-10,11-epoxides or benz[a]anthracene-10,11-diol-8,9-epoxides. 1,2-Epoxy-1,2,3,4-tetrahydrobenz[a]anthracene is the most mutagenic and cytotoxic of the nine derivatives and is 5 and 25 times more mutagenic than 3,4-epoxy-1,2,3,4-tetrahydrobenz[a]anthracene in bacterial and mammalian cells, respectively. In either test system, benz[a]anthracene 5,6-oxide (K-region oxide) has less than 10% of the activity of any of the 1,2-epoxides derived from benz[a]anthracene. The relative stabilities of the derivatives in aqueous solution do not account for the differences in mutagenic activity because the more mutagenic derivatives tend to be less stable. The benz[a]anthracene diol epoxides, like the benzo[a]pyrene diol epoxides, are refractory to the action of epoxide hydrase. The exceptional mutagenic activity of the 1,2-epoxide derivatives of benz[a]anthracene is consistent with and supportive of the hypothesis that bay region epoxides on saturated, angular benzo-rings of unsubstituted polycyclic aromatic hydrocarbons are ultimate carcinogens.

Benz(a)Anthracenes↗
PubMed1993

Characterization of highly polar bis-dihydrodiol epoxide--DNA adducts formed after metabolic activation of dibenz[a,h]anthracene.

Dibenz[a,h]anthracene as well as a biologically important metabolite of dibenz[a,h]anthracene, namely the M-region dihydrodiol trans-3,4-dihydroxy-3,4-dihydrodibenz[a,h]anthracene were in addition to further metabolism to a bay region diol epoxide, extensively transformed to a distal bisdihydrodiol, 3,4,10,11-tetrahydroxy-3,4,10,11-tetrahydro-dibenz[a,h]anthracene, which exhibited after renewed metabolic activation high DNA binding efficiency, leading to a new class of very polar DNA adducts. After incubation of dibenz[a,h]anthracene with DNA in the presence of liver microsomes from Aroclor 1254 treated male Sprague-Dawley rats highly polar DNA adducts probably originating from 3R,4R,10R,11R-tetrahydroxy-3,4,10,11-tetrahydrodibenz[a,h]an thracene and 3R,4R,10S,11S-tetrahydroxy-3,4,10,11-tetrahydrodibenz[a,h]anthr ace ne were identified by reversed phase HPLC and by the 32P-postlabeling method. The adducts obtained were further characterized by comparing their fluorescence spectra with those obtained from 3,4,10,11-tetrahydroxy- 3,4,10,11-tetrahydrodibenz[a,h]anthracene and from 3,4-dihydroxy-3,4-dihydrodibenz[a]anthracene, the putative chromophore of the polar adduct. DNA adducts formed via 3S,4S,10S,11S-tetrahydroxy-3,4,10,11-tetrahydro- dibenz[a,h]anthracene were not found. After incubation of 14C-labelled dibenz[a,h]anthracene highly polar DNA adducts derived from the bisdihydrodiol contributed 38% to the adducts found in the HPLC profile. Bay region diol epoxide adducts represented a fraction of 25%. Using the 32P-postlabelling technique a higher DNA binding yield for the racemic bisdihydrodiol (38 +/- 12 pmol/mg DNA) was calculated than for the most active 3,4-dihydrodiol enantiomer, 3R,4R-dihydroxy-3,4- dihydrodibenz[a,h]anthracene (23 +/- 6 pmol/mg DNA).

Animals↗
PubMed1975

Glutathione conjugates as metabolites of benz[a]anthracene.

1. [3H]Benz[a]anthracene is converted into water-soluble metabolites by microsomal plus soluble fractions of rat-liver in the presence of NADPH and glutathione. Chromatography on Sephadex G25 gave four radioactive peaks; the first contained hydrocarbon or hydrocarbon derivatives bound to soluble protein while the other three peaks contained glutathione conjugates of hydrocarbon metabolites. 2. Conjugates formed when either of the benz[a]anthracene metabolites, 5,6-dihydro-5,6-dihydroxybenz[a]anthracene or 8,9-dihydro-8,9-dihydroxybenz[a]anthracene, were similarly incubated were probably S-(5,6,8,9-tetrahydro-5,6,9-trihydroxybenz[a]anthracen-8-yl)glutathione and S-(5,6,8,9-tetrahydro-6,8,9-trihydroxybena[a]anthracen-5-yl)glutathione respectively. The corresponding peak obtained in the metabolism of benz[a]anthracene probably contains a mixture of these two isomers. 3. The third peak contained the conjugate, S-(5,6-dihydro-l-hydroxybenz-[a]anthracen-k-yl)glutathione, also formed by the conjugation of the "K-region" epoxide of benz[a]anthracene with glutathione. This was not formed in the metabolism of the dihydrodiols. 4. The fourth peak contained a new type of conjugate that is probably S-(8,9,10,11-tetrahydro-8,9,10-trihydroxybenz[a]anthracen-11-yl)glutathione. This conjugate is chromatographically similar to a product obtained from incubation of the 8,9-dihydrodiol, and is probably formed by microsomal oxidation of the 10,11-bond of the dihydrodiol, followed by conjugation of the resulting diol-epoxide with glutathione.

Animals↗
PubMed2002

Responses of Mycobacterium sp. LB501T to the low bioavailability of solid anthracene.

Several recent reports have indicated that some bacteria may have adapted to the low bioavailability of hydrophobic environmental chemicals and that generalizations about the bioavailability of compounds such as polycyclic aromatic hydrocarbons (PAHs) may be inappropriate. Experimental evidence and theoretical considerations show that the utilization of PAHs requires bioavailability-enhancing mechanisms of the bacteria such as: (1) high-affinity uptake systems, (2) adhesion to the solid substrate, and (3) biosurfactant excretion. We examined possible specific physiological responses of anthracene-degrading Mycobacterium sp. LB501T to poorly water-soluble anthracene in batch cultures, using solid anthracene as a sole carbon source. Mycobacterium sp. LB501T exhibited a high specific affinity for anthracene (a(o)A=32,500 l g(-1) protein h(-1)) and grew as a confluent biofilm on solid anthracene present as sole carbon source. No biofilm formation on anthracene was observed when excess glucose was provided as an additional substrate. This difference could be attributed to a modification of the cell surface of the bacterium. Anthracene-grown cells were significantly more hydrophobic and more negatively charged than glucose-grown cells. In adhesion experiments, anthracene-grown cells adhered 1.5- to 8.0-fold better to hydrophobic Teflon and up to 70-fold better to anthracene surfaces than glucose-grown cells. However, no production of biosurfactants was observed. Our results thus indicate that attachment and biofilm formation may be a specific response of Mycobacterium sp. LB501T to optimize substrate bioavailability.

Anthracenes↗
PubMed2006

Effects of anthracene on development of an arbuscular mycorrhizal fungus and contribution of the symbiotic association to pollutant dissipation.

The influence of anthracene, a low molecular weight polycyclic aromatic hydrocarbon (PAH), on chicory root colonization by Glomus intraradices and the effect of the root colonization on PAH degradation were investigated in vitro. The fungus presented a reduced development of extraradical mycelium and a decrease in sporulation, root colonization, and spore germination when exposed to anthracene. Mycorrhization improved the growth of the roots in the medium supplemented containing 140 mg l(-1) anthracene, suggesting a positive contribution of G. intraradices to the PAH tolerance of roots. Anthracene disappearance from the culture medium was quantified; results suggested that nonmycorrhizal chicory roots growing in vitro were able to contribute to anthracene dissipation, and in addition, that mycorrhization significantly enhanced anthracene dissipation. These monoxenic experiments demonstrated a positive contribution of the symbiotic association to anthracene dissipation in the absence of other microorganisms. In addition to anthracene dissipation, intracellular accumulation of anthracene was detected in lipid bodies of plant cells and fungal hyphae, indicating intracellular storage capacity of the pollutant by the roots and the mycorrhizal fungus.

Anthracenes↗
PubMed1994

Evaluation of the antimutagenic potential of anthracene: in vitro and ex vivo studies.

The present study was undertaken in order to evaluate the in vitro and ex vivo antimutagenicity of anthracene against the food-borne carcinogen IQ (2-amino-3-methylimidazo[4,5-f]quinoline). Anthracene caused a marked, concentration-dependent decrease in the mutagenicity of IQ in the Ames test, whether hepatic S9 or isolated microsomes from Aroclor 1254-induced rats served as the activation systems. Anthracene gave rise to a concentration-dependent inhibition of the 0-deethylation of ethoxyresorufin, a diagnostic probe for CYP1A (cytochrome P450 family 1, subfamily A) activity, and of the metabolic activation of Glu-P-1 (2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole, a diagnostic probe for CYP1A2. When microsomal metabolism of IQ was terminated by menadione, incorporation of anthracene into the incubation mixture once again inhibited the mutagenicity of IQ. All the above observations indicate that anthracene owes its antimutagenic response against IQ to: (a) inhibition of its CYP1A-mediated activation and (b) direct interaction between anthracene and the reactive intermediate(s) of IQ leading to their inactivation. Treatment of rats with anthracene did not greatly influence the ability of hepatic preparations to bioactivate IQ to mutagens. Similarly, administration of anthracene 2 h before sacrifice to Aroclor 1254-pretreated rats, did not modulate the hepatic activation of IQ. These findings demonstrate that the in vitro mechanisms of the antimutagenicity of anthracene are not operative in vivo, and further illustrate the inadequacy of in vitro studies, conducted in isolation, in predicting such effects.

Animals↗
PubMed1999

Ratio of the concentration of anthraquinone to anthracene in coastal marine sediments.

The ratio of the concentration of the oxidation product anthraquinone to that of its parent polycyclic aromatic hydrocarbon anthracene is reported for several coastal marine sediments. The ratio ranges from 0.317 in a highly contaminated industrialized harbor to 2.81 in a remote, less contaminated site. We hypothesize that differences in this ratio result from the input source of PAHs, with input from atmospheric deposition at remote sites resulting in a predominance of anthraquinone (ratio > 1), and direct discharge to highly contaminated industrialized harbors resulting in a predominance of anthracene (ratio < 1). To support this hypothesis, the fate of anthracene in the marine environment was investigated with respect to conversion to its oxidation product, anthraquinone. Once associated with sediments, anthracene is believed to be relatively persistent; however, it can potentially be subjected to oxidation via biological (microbial degradation) and chemical (chemical oxidation and photooxidation) processes. An assessment of the extent of oxidation of anthracene associated with sediments was conducted both under conditions simulating those found in the marine environment and under rigorous conditions by exposure to UV radiation. Results of this study show that while anthracene associated with marine sediments does not readily undergo oxidation to anthraquinone under conditions normally encountered in the marine environment, under extreme conditions anthracene is photooxidized by exposure to UV radiation. The extent of oxidation is influenced by sediment characteristics such as percent organic carbon, humic acid content and sediment surface area. The relative stability of anthracene under normal conditions may help to validate the use of the anthraquinone to anthracene ratio in marine sediments as an environmental marker of contaminant source.

Air Pollution↗
PubMed1978

Synthesis and carcinogenic activity of 5-fluoro-7-(oxygenated methyl)-12-methylvenz[a]anthracenes.

Treatment of 7,12-benz[a]anthraquinone (2) with methylmagnesium iodide or methyllithium yields mixtures of cis- and trans-7,12-dihydro-7,12-dihydroxy-7,12-dimethylbenz[a]anthracenes (3a,b), in which the ratio of cis to trans lies in the 3--4:1 region. Each isomer afforded high yields of 7-chloromethyl-12-methylbenz[a]anthracene (5) on treatment with hydrogen chloride in ethyl acetate. Similarly, 5-fluoro-7,12-benz[a]anthraquinone (8) afforded a mixture of cis- and trans-5-fluoro-7,12-dihydro-7,12-dihydroxy-7,12-dimethylbenz[a]anthracenes (9) which yielded 7-chloromethyl-5-fluoro-12-methylbenz[a]anthracene (10) on treatment with HCl. The chloromethyl compounds, 5 and 10, yielded 7-acetoxymethyl-12-methylbenz[a]anthracene (6) and 7-acetoxymethyl-5-fluoro-12-methylbenz[a]anthracene (11) on treatment with acetate ion. Hydrolysis of 6 and 11 yielded 7-hydroxymethyl-12-methylbenz[a]anthracene (7) and 5-fluoro-7-hydroxymethyl-12-methylbenz[a]anthracene (12), respectively. Since neither 11 nor 12 is appreciably carcinogenic, the carcinogenic metabolism of 7,12-dimethylbenz[a]anthracene (DMBA) probably does not involve attack at the 7-methyl group.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1973

Epoxy derivatives of aromatic polycyclic hydrocarbons. The preparation and metabolism of epoxides related to 7,12-dimethylbenz(a)anthracene.

The syntheses of 7,12-dimethylbenz[a]anthracene 5,6-oxide, 7-acetoxymethyl-12-methylbenz[a]anthracene 5,6-oxide and a product that appears to be mainly 7-hydroxymethyl-12-methylbenz[a]anthracene 5,6-oxide are described. The compounds readily rearranged to phenols in the presence of mineral acid, and 7,12-dimethylbenz[a]anthracene 5,6-oxide and its 7-hydroxymethyl derivative reacted slowly with water to yield trans-5,6-dihydro-5,6-dihydroxy-7,12-dimethylbenz[a] anthracene and trans-5,6-dihydro-5,6-dihydroxy-7-hydroxymethyl-12-methylbenz [a]anthracene respectively. Both epoxides were converted enzymically by rat liver microsomal fractions and homogenates into the related trans-dihydrodiols. The epoxides reacted chemically with GSH to form conjugates that were identical with the conjugates formed when the epoxides were incubated with rat liver homogenates. The GSH conjugates were more stable to acid than conjugates derived from other arene oxides. In the alkylation of 4-(p-nitrobenzyl)pyridine, 7,12-dimethyl-benz[a]anthracene 5,6-oxide was more active than the 5,6-oxides of 7-methylbenz[a]-anthracene and benz[a]anthracene.

Alkylation↗
PubMed1975

Metabolic pathways of 7,12-dimethylbenz[a]anthracene in hepatic microsomes.

High pressure liquid chromatography has enabled quantitative analysis of the in vitro metabolism of 7,12-dimethylbenz[a]anthracene, 7-methyl-12-hydroxymethylbenz[a]anthracene, 7-hydroxymethyl-12-methylbenz[a]anthracene, and 7,12-dihydroxymethylbenz[a]anthracene by 3-methylcholanthrene-induced and control rat liver microsomes. The following previously unrecognized metabolites have been tentatively identified: 5,6-dihydro-5,6-dihydroxy-7-methyl-12-hydroxymethylbenz[a]anthracene, 3-hydroxy-7,12-dihydrodihydroxymethylbenz[a]anthracene, 4-hydroxy-7,12-dihydrodihydroxymethylbenz[a]anthracene, and 8,9-dihydro-8,9-dihydroxy-7,12-dihydroxymethylbenz[a]anthracene. The epoxide hydratase inhibitor 1,2-epoxy-3,3,3-trichloropropane was found to eliminate all dihydrodiol formation and markedly inhibit the formation of several dimethylbenzanthracene metabolites. It is proposed that the tentatively identified 3-hydroxy and 4-hydroxy derivatives are formed by an enzymatic mechanism that does not involve epoxides as intermediates. The metabolic pathways of 7,12-dimethylbenz[a]anthracene in hepatic microsomal enzymes are proposed.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1995

Multiple DNA binding modes of anthracene-9-carbonyl-N1-spermine.

The poly(dAdT)2 complex of anthracene-9-carbonyl-N1-spermine, a spermine derivative terminally substituted with an anthracene moiety, has been studied using fluorescence, linear dichroism, circular dichroism, normal absorption spectroscopy (as a function of temperature) and computer modelling. For comparison, some data are also provided for the same ligand with poly(dGdC)2 and calf thymus DNA. Following detailed fluorescence and CD spectroscopic studies, we propose that anthracene-9-carbonyl-N1-spermine intercalates in at least two different binding orientations with poly(dAdT)2. Based on computer simulation data, we deduce that the ligand can intercalate from both the minor groove and the major groove. In contrast, intercalation with poly(dGdC)2 probably occurs only from the major groove. At high ligand concentrations, the CD spectra suggest anthracene-anthracene interactions, whilst the LD data point towards a groove-bound anthracene. Again from computer simulations, we propose binding modes consistent with these observations. Other data from the LD spectra suggest a sequential nature to the binding of the ligand to calf thymus DNA, with GC-rich sites being occupied first. At low ligand concentrations, anthracene-9-carbonyl-N1-spermine is able to stabilize poly(dAdT)2 against thermal decomposition, but not as effectively as spermine. The reverse is found to be true with calf thymus DNA. Both the anthracene-9-carbonyl-N1-spermine and spermine complexes of poly(dAdT)2 show pre-melt transitions in their melting curves. The anthracene-9-carbonyl-N1-spermine complex with poly(dAdT)2 also shows a post-melt transition.

Antineoplastic Agents↗
PubMed1995

Control of the depth of molecules within membranes by polar groups: determination of the location of anthracene-labeled probes in model membranes by parallax analysis of nitroxide-labeled phospholipid induced fluorescence quenching.

The location of anthracene-labeled molecules incorporated into model membranes was measured by fluorescence quenching. The depth of the anthracene group was calculated from the degree of quenching by lipids carrying a nitroxide at different depths, using the parallax analysis (Chattopadhyay & London (1987) Biochemistry 26, 39-45). A series of anthracene derivatives was examined in order to determine what polar functional groups would anchor at the membrane surface, and at what depth anchoring would occur. An anthracene with only a methyl group was not anchored at the membrane surface, but derivatives with polar or charged groups did anchor near the membrane surface as demonstrated by a shallower anthracene depth. Based on anthracene depths, protonated primary amine, secondary amine, and hydroxyl groups appear to be located 15-16 A from the center of the membrane. A quaternary amino locates more shallowly, at 18 A from the bilayer center. A protonated carboxyl group is slightly deeper, at 14 A from the center of the bilayer. Ester groups are found to be weakly anchoring, having a location dependent on the structure of the molecule to which they are attached. In methyl 9-anthracenepropionate, the ester group is located about 13 A from the bilayer center. Anthracene esters attached to cholesterol or cholesterol esters showed various depths. An anthracene ester attached to the tail of cholesterol was located 1-6 A from the center of the bilayer for a cholesterol derivative, but at 12 A from the bilayer center for a cholesterol oleate derivative.(ABSTRACT TRUNCATED AT 250 WORDS)

Anthracenes↗
PubMed1984

Photo-induced dimerization of anthracene phospholipids for the study of the lateral distribution of lipids in membranes.

It is shown that photo-induced cross-linking reaction between anthracene-labelled phospholipids can be used for studying, at a molecular level, their lateral distribution in bilayer structures. A simple and versatile method is proposed. It is based on the property of anthracene to form covalently bound dimers upon irradiation in the near ultraviolet (360 nm) and on the possibility of separating the lipid photo-dimers from the lipid monomers by thin-layer chromatography. Identification of the photo-dimers is easily achieved since, upon illumination at a shorter wavelength (250-280 nm), they partially dissociate to the native monomer molecules. The feasibility of the method was tested by checking the effects of cations (sodium, calcium) on the homogeneity of 1/1 mixtures of anthracene-phosphatidylcholine, i.e. 1-acyl-2-[9-(2-anthryl)-nonanoyl]-sn-glycero-3-phosphocholin e (Anthr-PC) with anthracene-phosphatidic acid (Anthr-PA) and with anthracene-phosphatidylglycerol (Anthr-PG) in the form of liposomes. These lipids were anthracene-labelled by acylation of their glycerol backbone at the sn-2 position with the synthetic 9-(2-anthryl)-nonanoic acid. Data presented indicate a good miscibility of these lipids in the presence of sodium. For each lipid mixture, the lipid heterodimers were clearly identified and, quantitatively, they dominated the lipid homodimers, as expected for a regular distribution of the lipids in the 1/1 mixture. Addition of calcium ions to the lipid suspensions did not alter the miscibility properties of Anthr-PC and Anthr-PG. In contrast, calcium triggered a clear-cut phase separation in the Anthr-PC/Anthr-PA mixture as, in this case, only traces of the heterodimer form of the lipids remained observable on the chromatogram. The three anthracene-phospholipids, pure or mixed together, exhibit a clear-cut gel-to-liquid phase transition which was detectable by fluorescence intensity measurements. The analysis of the corresponding phase-transition temperatures confirms, at a 'macroscopic' level, the effects of sodium and calcium on the mixing properties of the anthracene phospholipids which were revealed at a 'microscopic' level by the dimerization procedure.

Anthracenes↗
PubMed2001

Efficient preparation of monoadducts of [60] fullerene and anthracenes by solution chemistry and their thermolytic decomposition in the solid state.

The efficient preparation of monoadducts of [60]fullerene and seven anthracenes (anthracene, 1-methylanthracene, 2-methylanthracene, 9-methylanthracene, 9,10-dimethylanthracene, 2,3,6,7-tetramethylanthracene, and 2,6-di-tert-butylanthracene) by cycloaddition in solution is described. The seven mono-adducts of [60]fullerene and the anthracenes were characterized spectroscopically and were obtained in good yields as crystalline solids. The monoadducts of [60]fullerene and anthracene, 1-methylanthracene, 2-methylanthracene and 9,10-dimethylanthracene crystallized directly from the reaction mixture. The thermolytic decomposition at 180 degrees C of the crystalline monoadducts of [60]fullerene and anthracene, 1-methylanthracene, 9-methylanthracene and 9,10-dimethylanthracene all gave rise to the specific formation of a roughly 1:1 mixture of [60]fullerene and the corresponding antipodal bisadducts ("trans-1"-bisadducts) of [60]fullerene and the anthracenes. In contrast, the crystalline monoadducts of [60]fullerene and the anthracene derivatives 2-methylanthracene, 2,3,6,7-tetramethylanthracene and 2,6-di-tert-butylanthracene all decomposed to [60]fullerene and anthracenes (without detectable formation of bisadducts) upon heating in the solid state to temperatures of 180 to 240 degrees C. The formation of the antipodal bisadducts from thermolytic decomposition of crystalline samples of the monoadducts was rationalized by topochemical control.

Journal Article↗
PubMed1988

Metabolism of 7,12-dimethylbenz[a]anthracene by mouse mammary epithelial cells cultured serum-free inside collagen gels.

Mammary epithelial cells from 3-4-month-old BALB/c virgin mice were cultured inside collagen gels in the following serum-free media: Dulbecco's Modified Eagle's Medium/Ham's F-12 (1:1) supplemented with (A) insulin, bovine serum albumin, epidermal growth factor; (B) insulin, bovine serum albumin, progesterone, prolactin; (C) insulin, bovine serum albumin, progesterone, prolactin, linoleic acid. Cell number increased with all media used. At day 7 of culture, [3H]dimethylbenz[a]anthracene (DMBA) was added to the cultures and its metabolism to water soluble and organic soluble compounds was determined. Mouse mammary epithelial cells were able to metabolize [3H]DMBA to water and organosoluble metabolites. By 72 h, 77-94% of the added DMBA had been metabolized by the epithelial cells in the three media to water and organosoluble metabolites in equivalent amounts. The distribution between water soluble and organosoluble metabolites was approximately equivalent. The high pressure liquid chromatography profiles of organosoluble fractions from the media indicated that the major products appeared to be the phenols, 2-,3-, or 4-hydroxydimethylbenz[a]anthracene, the hydroxymethyl derivatives, 7-methylbenz[a]anthracene and 7-hydroxymethylbenz[a]anthracene, trans-3,4-dihydro-3,4-dihydroxydimethylbenz[a]anthracene and one or two major fractions eluting just behind the marker cis-5,6-dihydro-5,6-dihydroxydimethylbenz[a]anthracene. The major fraction eluting just ahead of the cis-5,6-dihydro-5,6-dihydroxydimethylbenz[a]anthracene was most likely trans-8,9-dihydro 8,9-dihydroxydimethylbenz[a]anthracene. The profiles were similar for the cells cultured in all three serum-free media. The results demonstrate that mouse mammary epithelial cells cultured inside collagen gels with serum-free media can metabolize DMBA to putative carcinogenic forms.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2003

Assessment of the toxicity of anthracene photo-modification products using the topminnow (Poeciliopsis lucida) hepatoma cell line (PLHC-1).

Many polycyclic aromatic hydrocarbons (PAHs) are acutely toxic to fish and other aquatic organisms in the presence of environmentally realistic intensities of solar ultraviolet radiation (SUVR). In this study, the cytoxicity/phototoxicity of anthracene photo-modified products to aquatic animals was assessed based on in vitro toxicity assays using a fish hepatoma cell line (PLHC-1 cell line). The results from this study showed that pre-exposure of anthracene/cell culture media to SUVR caused a significant amount of photo-modification and reduced the phototoxicity of parent anthracene compound. SUVR pre-exposed anthracene did not induce cytotoxicity in the absence of SUVR. It was shown that in comparison with anthracene, two major anthracene photo-modified products (anthraquinone, 1,2-dihydroxyanthraquinone) were significantly less phototoxic to PLHC-1 cells. Also in the absence of SUVR, these chemicals did not induce any detectable cytotoxicity to PLHC-1 cells. In conclusion, this study demonstrated that photo-modification reduced the phototoxicity of anthracene to PLHC-1 cells because major anthracene photo-modified products are not phototoxic. Also it was found that these photo-modified anthracene products were not cytotoxic in the absence of SUVR. This study indicated the need for separate toxicity assessments of individual photo-modified PAH products in both animal and plant models.

Animals↗
PubMed2002

The sorption of anthracene onto goethite and kaolinite in the presence of some benzene carboxylic acids.

The uptake of anthracene from dilute aqueous solutions onto goethite and kaolinite was investigated at 25 degrees C, first in the absence and then in the presence of three benzene carboxylic acids: phthalic acid (benzene-1,2-dicarboxylic acid), trimesic acid (-1,3,5-), and mellitic acid (-1,2,3,4,5,6-). Carboxylic acid concentrations were 0.20, 0.10, and 0.05 mM. Anthracene (0.20 microM) did not adsorb strongly onto the pure mineral surfaces, but in the presence of phthalic acid a substantial increase in anthracene uptake was observed, particularly for the goethite systems. Trimesic and mellitic acids did not enhance anthracene uptake. Phthalate and proton adsorption data have been used to model phthalate adsorption onto the mineral surfaces using an extended constant capacitance surface complexation model. This model was then successfully adapted to account for the observed increase in anthracene uptake, where anthracene molecules were assumed to interact with adsorbed phthalate. We propose that the enhancement of anthracene adsorption in the presence of phthalic acid is due to an increase in the hydrophobicity of the mineral surface once phthalic acid molecules adsorb. The same effect was not observed for the other benzene carboxylates because of their greater polarity.

Acids, Carbocyclic↗