7,12-dimethylbenz[a]anthracene appears as yellow to greenish-yellow crystals or a yellow solid. Odorless. Maximum fluorescence at 440 nm. Bluish-violet fluorescence in UV light. (NTP, 1992)
颜色/状态:
Plates, leaflets from acetone-alcohol, faint greenish-yellow tinge
气味:
Odorless[NOAA; CAMEO Chemicals. Database of Hazardous Materials. 7,12-Dimethylbenz
溶解度:
In water, 0.061 mg/L water at 25 °C
蒸汽压力:
6.8X10-7 mm Hg at 25 °C
稳定性/保质期:
- 存在于烟气中。
- 具有致癌性。
分解:
Hazardous decomposition products formed under fire conditions - Carbon oxides.[Sigma-Aldrich; Safety Data Sheet for 7,12-Dimethylbenz
Because of the high incidence of pancreatic cancer in the United States and because of the correlation of pancreatic cancer to environmental exposure, we have undertaken experiments to measure the metabolism of the carcinogen 7,12-dimethylbenzanthracene in the pancreas of the Long-Evans male rat. This study examined the in vitro metabolism of the carcinogen and found the production of aqueous products in pancreas to be similar to that in liver, however, the pancreatic capability was not induced to greater metabolism by pretreatment with either phenobarbital or 3-methylcholanthrene. High pressure liquid chromatographic analysis of the in vitro products of pancreatic metabolism demonstrated a relatively greater abundance of 5,6-epoxy-7-hydroxymethyl-12-methylbenzanthracene than the liver and a relatively less abundance of 7-hydroxymethyl-12-methylbenzanthracene and 7-methyl-12-hydroxymethylbenzanthracene than the liver. Carcinogen levels were measured in pancreas, liver, bile and blood at 2, 5, 10, 16, 22 and 36 hours after injection.
The homogeneous 3 alpha-hydroxysteroid-dihydrodiol dehydrogenase of rat liver cytosol catalyzes the NADP-dependent oxidation of a wide variety of polycyclic aromatic trans-dihydrodiols and has been implicated in their detoxification. This study examined the influence of methyl groups on the velocity and stereochemical course of enzymatic benz(a)anthracene (BA) trans-dihydrodiol oxidation. The racemic trans-3,4-dihydrodiols of BA and 7-methylbenz(a)anthracene (7-MBA) were completely consumed by the purified dehydrogenase, indicating that both stereoisomers are substrates. However, 50% of the ( +/- )-trans-3,4-dihydrodiols of 12-methylbenz(a)anthracene (12-MBA) and 7,12-dimethylbenz(a)-anthracene (DMBA) were oxidized, suggesting that only one stereoisomer is utilized in each case. At low substrate concentrations, enzymatic oxidation of the trans-3,4-dihydrodiols of BA, 12-MBA, and DMBA followed simple first-order kinetics. By contrast, oxidation of the 3,4-dihydrodiol of 7-MBA was of higher order, due to differences in the rate of oxidation of each stereoisomer. Rate constants estimated for each reaction indicate that the non-bay-region methyl group at position 7 has a greater enhancing effect on the rate of oxidation than the bay-region methyl group at position 12 (10- versus 4-fold, respectively). The 3,4-dihydrodiol of DMBA, which possesses both non-bay- and bay-region methyl groups, is oxidized more than 30 times faster than the unmethylated parent hydrocarbon. The absolute stereochemistry of the preferentially oxidized dihydrodiols was assigned by circular dichroism spectrometry. For the 3,4-dihydrodiols of DMBA and 12-MBA, the stereoisomer oxidized has the 3S,4S configuration. A large negative Cotton effect was observed in the circular dichroism spectrum of the 7-MBA 3,4-dihydrodiol which remained at the end of the rapid phase of oxidation of this racemic substrate, indicating that the dehydrogenase displays partial stereochemical preference for the 3S,4S enantiomer. These results suggest that methylation of BA at C-7 greatly enhances the oxidation of the 3S,4S-dihydrodiol, while the presence of a bay-region methyl group at C-12 completely blocks the oxidation of the 3R,4R-stereoisomer. Rapid, stereoselective oxidation of methylated polycyclic aromatic trans-dihydrodiols by this route in vivo may significantly influence their carcinogenicity.
Earlier studies ... demonstrated that benz[a]anthracene (BA), 7-methylbenz[a]anthracene (7-MBA) and 12-methylbenz[a]anthracene (12-MBA) undergo a bio-alkylation substitution reaction in the meso-anthracenic position(s) or L-region leading to the biosynthesis of the potent carcinogen 7,12-dimethylbenz[a]anthracene (7,12-DMBA). These results support the hypothesis that for most, if not all, unsubstituted polycyclic aromatic hydrocarbon carcinogens, the chemical or biochemical introduction of an alkyl group in the meso-anthracenic position(s) or L-region is a structural requirement for strong carcinogenic activity. Here we report that the L-region methyl derivatives 7-MBA, 12-MBA and 7,12-DMBA are oxidized to hydroxymethyl derivatives by a rat liver cytosol preparation without any apparent oxidation of the ring positions.
Yields 8,9-dihydro-8,9-dihydroxy-7,12-dimethylbenzanthracene, 7-hydroxymethyl-12-methylbenzanthracene, 12-hydroxymethyl-7-methylbenzanthracene in rat, guinea pig, pig and hamster. /From table/
7,12 Dimethylbenzanthracene has known human metabolites that include Benz(a)anthracene-8,9-diol, 7,12-dimethyl-, 7-Hydroxymethyl-12-methylbenz[a]anthracene, 7,12-Dimethylbenz(a)anthracene-5,6-diol, BENZ(a)ANTHRACENE-3,4-DIOL, 7,12-DIMETHYL-, 12-Hydroxymethyl-7-methylbenz(a)anthracene, and BENZ(a)ANTHRACEN-2-OL, 7,12-DIMETHYL-.
IDENTIFICATION AND USE: 7,12-Dimethylbenz(a)anthracene (DMBA) is a solid. It is used mainly as a research chemical in experimental medicine. HUMAN EXPOSURE AND TOXICITY: 7,12-DMBA is one of the most powerful synthetic carcinogens. In humans, it may be an initiator when applied to the skin. Low mutagenic effects were noted for DMBA when tested in human cell cultures with metabolic activation, but practically no effects were noted when tested without activation. ANIMAL STUDIES: After 50-day-old female rats were fed DMBA at either 112 or 133 mg/kg body wt, pancytopenia accompanied by severe depression of hematopoietic and lymphoid precursors developed within weeks. Weekly intravenous injection of DMBA produced dermal melanocytomas and tumors of the forestomach, intestine, ovary, skin subcutis, and lymphoreticular tissue in the Syrian hamster. DMBA admin in single ip doses of 80 mg/kg in corn oil destroyed primordial oocytes in mouse ovaries. DMBA, significantly enhances the overall embryotoxicity in avian species. In rodent cell tests, nonactivated DMBA exhibits weak and activated DMBA moderate mutagenic effects. It also causes sister chromatid exchanges and chromosomal aberrations. Mammalian cell transformation tests for DMBA were slightly positive with metabolic activation. ECOTOXICITY STUDIES: Groups of at least 145 guppies (6 to 11 days old) of the king cobra strain (Poecilia reticulata) were exposed for 6 hours each week for 4 weeks to DMBA. Hepatic neoplasms developed in guppies exposed to the intermediate and high concentration. In addition to liver neoplasms, several other types of lesions developed in DMBA exposed guppies.
Because some epidemiology studies and initiation/promotion studies in rats have suggested a potential for increased breast cancer rates with increasing magnetic field exposure, the ability of 50- and 60-Hz magnetic fields to promote mammary gland tumors initiated by the administration of 7,12-dimethylbenz(a)anthracene (DMBA) was examined in female Sprague-Dawley rats in 13- and 26-week whole-body exposure studies. ... In an initiation/promotion study in which female Sprague-Dawley rats were initiated by four weekly doses of 5 mg DMBA per rat beginning at 50 days of age and exposed to 50-Hz magnetic fields at 1 or 5 G field intensities or to 1 G 60-Hz magnetic fields for 13 weeks, there was no evidence that magnetic fields promoted the development of mammary gland neoplasms. The prevalence and multiplicity of mammary gland carcinomas in all DMBA groups limited the ability of this assay to detect a promoting effect of magnetic fields. In an initiation/promotion study in which female Sprague-Dawley rats were initiated by four weekly doses of 2 mg DMBA per rat beginning at 50 days of age and exposed to 50-Hz magnetic fields at 1 or 5 G field intensities for 13 weeks, there was no evidence that magnetic fields promoted the development of mammary gland neoplasms. In an initiation/promotion study in which female Sprague-Dawley rats were initiated by a single 10 mg DMBA dose at 50 days of age and then exposed to 50-Hz magnetic fields at 1 or 5 G field intensities or to 1 G 60-Hz magnetic fields for 26 weeks, there was no evidence that magnetic fields promoted the development of mammary gland neoplasms.
/The objective was/ to investigate the induction of neoplastic lesions under the action of ultraviolet B radiation (UVR-B) and dimethylbenzanthracene (DMBA). Forty Wistar rats were assigned to four groups (ten animals each), according to the procedure: group A received UVR-B irradiation, group B received topic DMBA, group C, UVR-B+DMBA and group D as control, observed for ten weeks. In the tenth week they went through a skin biopsy and histopathological study. The average thickness of the epidermis was calculated and evaluated statistically. Macroscopic lesions in group B were more of inflammatory kind compared to group A. Group C presented more injuries with neoplastic features than the others (p<0.01). Histologically there was a significant increase in thickness of the epidermis of all groups compared to control, however the greatest thickness measures occurred in Group C (p<0.01). The population exposed to ultraviolet B radiation is subject to suffer skin lesions that can develop into cancer. The association with hydrocarbons as the dimethyl benzanthracene increases the possibility of malignancy. ...
Vegetables of the Cruciferae family contain high levels of glucosinolates, metabolites of which are believed to enhance detoxification. Spanish black radishes (SBR) contain 4x more glucosinolates than other crucifers. This study examined whether feeding mice a diet containing 20% SBR for 2 wk could enhance metabolism of 7,12-dimethylbenz(a)anthracene (DMBA) and inhibit DMBA-mediated bone marrow toxicity. Expression of Phase I and II detoxification enzymes was significantly greater for mice fed SBR than control diet. Six hours after DMBA administration, the blood levels of DMBA in mice fed the SBR diet were significantly lower than mice fed a control diet. DMBA reduced bone marrow cells in mice fed control diet to a significantly greater extent than mice fed the SBR diet. Colony forming assays demonstrated that mice on the SBR diet had 1) less reduction in lymphoid CFU-preB progenitor cells, 2) greater recovery of CFU-preB progenitor cells at 168 hr, and 3) less reduction of CFU-GM progenitor cells at 6 hr. Therefore, mice fed a 20% SBR diet for 2 wk had greater expression of detoxification enzymes, faster metabolism of DMBA, and a reduction in DMBA-induced bone marrow toxicity. Overall, these results support the hypothesis that glucosinolates in SBR are protective against acute toxicity.
Human lymphocytes were exposed to binary mixtures of the mutagens B[a]P, DMBA, Trp-P-1 and MX for 1 hour with or without S9. Viability was assessed with trypan blue dye and the genotoxicity by the comet assay. All of the hydrocarbon showed an effect with furanone. With and without S9, the most toxic interactions were observed between hydrocarbons. Synergistic interaction was observed without S9 between B [a] P and Trp-P-1 and between DMBA and Trp-P-1 with metabolic activity. Without S9 antagonistic interaction was observed only between Trp-P-1+DMBA, and with S9 between Trp-P-1+MX and MX+DMBA. It observed an increase dose dependent in tail length. Half the cultures showed genotoxic damage and increased cell damage. ...
Studies in animals indicate that ... 7,12-dimethylbenz(a)anthracene ... readily absorbed from intestinal tract and tends to localize primarily in body fat and fatty tissues such as breast. ... The distribution of radioactivity in rats after admin of labeled ... /cmpd/ by stomach tube was ... studied. Major route of excretion was found to occur via the bile into the feces. There was rather prolonged retention of radioactivity in body fat, ovaries, and adrenals.
来源:Hazardous Substances Data Bank (HSDB)
吸收、分配和排泄
7,12-DMBA 以 20 mg/kg 的剂量口服给予大鼠,溶解在淋巴中乳糜微粒的脂质部分中。
7,12-DMBA orally administered to rats at 20 mg/kg dissolved in the lipid fraction of the chylomicrons in the lymph.
48 hr after oral admin, 90% was excreted by mice. Pretreatment of mice with 3-methylcholanthrene slightly incr initial rate of 7,12-DMBA elimination, but after 48 hr amt of residual 7,12-DMBA was the same as that in the nonpretreated mice. Ethyl acetate extractable polar metabolites and water-sol metabolites were more abundant in urine and feces of pretreated mice than in nonpretreated ones.
Two hr after ip injection, 7,12-dimethylbenz(a)anthracene (DMBA) was present throughout the body of Amazon mollies, except in brain and ovary. There was an enhanced deposition at 4 sites, in macrophages of atrium of heart and peritoneum, liver, and exocrine pancreas. DMBA was taken up by reticuloendothelial macrophages for 78 hr after injection, then it was lost. Accumulation and disapperance of radioactive label seen in liver and pancreatic cells probably represented pattern of metab of compd. By 400 hr after injection there was little DMBA remaining. Label accumulated in ameloblasts, which secrete the enamel capping of the teeth. No preferential metab of DMBA by spleen was observed.
Pheromone content of azinphosmethyl-susceptible and -resistant obliquebanded leafrollers (Lepidoptera: Tortricidae) as a function of time of day and female age
作者:Ashraf M. El-Sayed、R.M. Trimble
DOI:10.4039/ent134331-3
日期:2002.6
Abstract
The effect of time of day and age on the amounts and ratios of four pheromone compounds [(Z)-11-tetradecenyl acetate (Z11-14:Ac), (E)-11-tetradecenyl acetate (E11-14:Ac), (Z)-11-tetradecenol (Z11-14:OH), and (Z)-11-tetradecenal (Z11-14:Al)] was compared in azinphosmethyl-susceptible (susceptible) and -resistant (resistant) female obliquebanded leafrollers, Choristoneura rosaceana (Harris). The amounts of all four pheromone compounds varied during the hour before and five hours after the onset of scotophase. The glands of resistant females contained approximately one half the amount of Z11-14:Ac and Z11-14:OH as the glands of susceptible females during the second and third hours of scotophase, and between 50 and 70% as much Z11-14:Al as the glands of susceptible females during the hour before and second to fourth hours of scotophase. The glands of susceptible and resistant females contained similar amounts of E11-14:Ac. The relative amounts of each of the four pheromone compounds were affected by time of day but not by resistance status. There was a negative linear relationship between the amounts of each of the four compounds and female age in both types of females. The amounts of Z11-14:Ac and E11-14:Ac declined at similar rates with age in susceptible and resistant females; the amounts of Z11-14:OH and Z11-14:Al declined more rapidly with age in susceptible than in resistant females. The relative amounts of the four compounds were not affected by female age. Temporal variation in the relative amounts of pheromone in susceptible and resistant C. rosaceana may be associated with similar variation in the emission of pheromone and corresponding temporal variation in the relative attractiveness of the two types of females.
Synthesis of Adducts Formed by Iodine Oxidation of Aromatic Hydrocarbons in the Presence of Deoxyribonucleosides and Nucleobases
作者:Aaron A. Hanson、Eleanor G. Rogan、Ercole L. Cavalieri
DOI:10.1021/tx980127q
日期:1998.10.1
hydrocarbons (PAH) undergo two main pathways of metabolicactivation related to the initiation of tumors: one-electronoxidation to give radical cations and monooxygenation to yield bay-region diol epoxides. Synthesis of standard adducts is essential for identifying biologically formed adducts. Until recently, radical cation adducts were synthesized by oxidation of the PAH in an electrochemical apparatus
De Novo Design of Selective Quadruplex–Duplex Junction Ligands and Structural Characterisation of Their Binding Mode: Targeting the G4 Hot‐Spot
作者:Laura Díaz‐Casado、Israel Serrano‐Chacón、Laura Montalvillo‐Jiménez、Francisco Corzana、Agatha Bastida、Andrés G. Santana、Carlos González、Juan Luis Asensio
DOI:10.1002/chem.202005026
日期:2021.4.7
Targeting the interface between DNA quadruplex and duplex regions by smallmolecules holds significant promise in both therapeutics and nanotechnology. Herein, a new pharmacophore is reported, which selectively binds with high affinity to quadruplex–duplex junctions, while presenting a poorer affinity for G‐quadruplex or duplex DNA alone. Ligands complying with the reported pharmacophore exhibit a
Synthesis and structure determination of the adducts of the potent carcinogen 7,12-dimethylbenz[a]anthracene and deoxyribonucleosides formed by electrochemical oxidation: models for metabolic activation by one-electron oxidation
作者:N. V. S. RamaKrishna、Ercole L. Cavalieri、E. G. Rogan、G. Dolnikowski、R. L. Cerny、M. L. Gross、H. Jeong、R. Jankowiak、G. J. Small
DOI:10.1021/ja00031a047
日期:1992.2
Anodic oxidation of 7,12-dimethylbenz[a]anthracene (7,12-DMBA) in the presence of dG yields four adducts and one oxygenated derivative of 7,12-DMBA: 7-methylbenz[a]anthracene (MBA)-12-CH 2 -C8dG (13%), 7-MBA-12-CH 2 -N7Gua (55%), 12-MBA-7-CH 2 -N7Gua (12%), 7-MBA-12-CH 2 -C8Gua (10%), and 7,12-(CH 2 OH) 2 -BA (10%). The first three are primary products of the electrochemical reaction, whereas the last
Effect of Ultraviolet Light on Polycyclic Hydrocarbons in Sterol Surface Film Systems
作者:W. W. Davis、M. E. Krahl、G. H. A. Clowes
DOI:10.1126/science.94.2448.519
日期:1941.11.28
2-benzanthracenes and other polycyclic hydrocarbons, when irradiated either in bulk aqueous suspensions or in the comparable excess phase under mixed surface films, were converted rapidly by ultraviolet light to photo-oxides. When held in two-dimensional solution or molecular association with sterols in mixed surface films at the air-water interface, the hydrocarbons were protected from such photodecomposition