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PubMed1991

Preparation of potentially bioactive aza and thiaza polycyclic compounds containing a bridgehead nitrogen atom synthesis and antimicrobial activity of some pyrrolo[1,2,3-de]-1,4-benzothiazines.

The synthesis of the 2,3-dihydro-pyrrolo[1,2,3-de]-1,4-benzothiazine 1a and 11b, 12-dihydro-isoquino[1,2-c]-1,4-benzothiazine 8 has been accomplished by using a Bischler type cyclization of the N-(2,2-diethoxyethyl)-3,4-dihydro-2H-1,4-benzothiazines 3a and 3d, respectively. The new compounds 1a and 8 together with the known pyrrolobenzothiazines 1b,c and some their derivatives and intermediates of preparation were tested in vitro for their antimicrobial activity. Compound 1b was the most active against the Gram-positive Bacillus subtilis. Compound 7b showed interesting antifungal activity when tested against Saccharomyces cerevisiae.

Anti-Bacterial Agents↗
PubMed2000

Solid-phase extraction of polycyclic aromatic compounds.

Solid-phase extraction (SPE) for two groups of polyaromatic compounds--polycyclic aromatic hydrocarbons and naphthalenesulfonates--with completely different problems in the extraction process are reviewed. The sorbents used in each case and the different steps of SPE are studied. Particular problems encountered in the SPE of each group are described. Adsorption problems of PAHs which require an organic solvent or a surfactant to be added to the sample are explained. The need of ion-pair solid-phase extraction for extracting naphthalenesulfonates and the influence of the inorganic species in the extraction are discussed. The on-line systems are described for both group of compounds.

Chromatography, Gas↗
PubMed2002

Identification of atmospheric volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and carbonyl compounds in Hong Kong.

Volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and carbonyl compounds are the major organic pollutants in the atmosphere. Emissions from motor vehicles have been one of the primary pollution sources in the metropolitan area of Hong Kong. A 12-month monitoring program for VOCs, PAHs and carbonyl compounds was performed at a roadside urban station at Hong Kong Polytechnic University (HKPU) in order to determine the correlations of each selected pollutant. The monitoring program ran from 16 April 1999 to 10 April 2000 for a period of 1 year, and a 2-week winter intensive sampling was carried out during January 2000. Traditionally, emission sources are identified from organic compounds in air particulates. Since many of the gaseous and particulate phases of organic compounds are from the same sources, correlations between the major exhausts are to be expected. Therefore, it would be more effective to apportion the sources using the combined gaseous and particulate phases of organic compounds. Correlations of selected pollutants within two other toxic air pollutants (TAPs) monitoring stations in Tsuen Wan (TW) and Central/Western (CW) were analyzed. Good correlations were found between pollutants that came from vehicle exhaust, especially in intensive sampling periods at HKPU roadside station. This was because the washing out effect for particulates during rainy days and photochemical degradation during high solar radiation were minimized in wintertime.

Air Pollutants↗
PubMed1978

Hepatic mixed-function oxidase activity in rainbow trout exposed to several polycyclic aromatic compounds.

The effects of polycyclic aromatic hydrocarbons (PAHs) on microsomal liver enzymes were examined in rainbow trout. Various PAHs (naphthalene through benzo(a)pyrene [B(a)P]) were injected ip to screen for mixed-function oxidase (MFO) activity. Chrysene, B(a)P, and Aroclor 1254 caused MFO induction. When fish were also exposed to solubilized pyrene, fluoranthene, and B(a)P in water, bioaccumulation of B(a)P resulted in MFO induction, whereas bioaccumulation of pyrene and fluoranthene did not. Based on water and injection exposure to B(a)P, it was predicted that tissue concentrations in excess of 300 micrograms/kg B(a)P would be accompanied by MFO induction in rainbow trout.

Animals↗
PubMed1990

The initiator tRNA acceptance assay as a short-term test for carcinogens. 6. Results with 78 polycyclic aromatic compounds.

A total of 78 polycyclic aromatic compounds (PAH), including pure hydrocarbons, PAH metabolites, aromatic amines and nitroarenes, were tested in the initiator tRNA acceptance assay (tR assay) for carcinogens. Among the pure hydrocarbons, all strong carcinogens were highly active in the tR assay. Some weak carcinogens showed moderate positive responses, others as well as all possible non-carcinogens were inactive. Various PAH metabolites, including phenols, dihydrodiols, arene oxides, dihydrodiol epoxides, quinones and benzylic sulfate esters, were positive as well. Strikingly, however, their effects rarely reached the levels observed with the strong carcinogens among the pure hydrocarbons. Moreover, the correlation with carcinogenicity was less clear, partially due to limitations in the available carcinogenicity data. The activities in the tR assay were also compared with the mutagenicity in Salmonella typhimurium. No appreciable correlation was observed. For example, trans-9,10-dihydroxy-9,10-dihydrobenzo[c]chrysene, in the absence of a mammalian metabolic system, was highly active in the tR assay, but non-mutagenic. Upon addition of rat liver enzymes, the reverse result was obtained. syn-Benzo[c]chrysene-9,10-dihydrodiol-11,12-oxide, on the other hand, was a potent direct mutagen, but required the presence of liver microsomes for a positive response in the tR assay. Thus, the metabolic basis for these two activities is different, and not yet understood for the tR assay. The partial correlations in the tR assay and in the Salmonella mutagenicity assay with carcinogenicity, and the pronounced discrepancies between these in vitro tests, may suggest that they detect different mechanisms involved in carcinogenicity. However, the tR assay was less predictive for the carcinogenicity of PAHs as compared to the previously investigated N-nitroso compounds and mycotoxins.

Carcinogenicity Tests↗
PubMed1990

The relationship between mutagenicity and chemical composition of polycyclic aromatic compounds from coal pyrolysis.

The polycyclic aromatic compounds (PAC) produced from the pyrolysis of a bituminous coal at temperatures of 1125 to 1425 degrees K prove to be mutagenic to S. typhimurium, both in the presence and in the absence of postmitochondrial supernatant (PMS) prepared from Aroclor 1254-induced rat liver. Mutagenicity of the PAC samples measured in the absence of PMS exhibits little dependence on pyrolysis temperature; that measured in its presence is higher at the higher pyrolysis temperatures. However, because of the decrease in PAC yield as the temperature is raised, mutagenicity per mass of coal consumed falls with an increase in temperature if measured without PMS (-PMS) and peaks at an intermediate temperature of 1378 degrees K if measured with PMS (+PMS). Using a new chromatographic technique, we have split each coal-derived PAC sample into two fractions: LC1, containing PAC with alkyl and O-containing substitutions and LC2, consisting of unsubstituted PAC. Substituted (LC1) fractions show no significant +PMS mutagenicity, indicating that, as a whole, the alkylated PAC in our coal pyrolysis products are not mutagenic. Only at the higher temperatures do the substituted fractions exhibit significant -PMS mutagenicity, attributed to PAC with carbonyl or etheric functionalities. The extremely low yields of the substituted PAC under the conditions where they show some activity, however, ensure that they contribute little to overall mutagenicity. In contrast to the substituted fractions, the unsubstituted (LC2) fractions display significant mutagenicity under all conditions and appear to be responsible for virtually all of the mutagenicity in these coal-derived PAC samples. In this fraction, -PMS activity is attributed to nitrogen-containing heterocyclic aromatics.

Animals↗
PubMedDate not supplied

Polycyclic aromatic compounds: extraction and determination in food.

Polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic compounds (PACs) in general, comprise the largest class of known environmental carcinogens. Reports of some studies of total diet in a number of developed countries indicate that food constitutes an important source of exposure of man to PACs, although other authors have shown the need to develop accurate data, in order that the overall public health hazard may be effectively evaluated and controlled. In this context, this review aims to give an overview of methods used to determine the PAC content of foodstuffs. At first, the nature, classification and derived compounds of PAHs are considered. Likewise, the occurrence of PAHs in processed and in non-processed foods is shown. The main causes are environmental contamination and the utilization of procedures which give rise to the presence of PACs during the processing, preservation, and packaging of foods. Octanol: water partition coefficients of PACs and their relationships with some properties, such as aqueous solubility and bioaccumulation, are considered. The solubility of complex mixtures of PACs in several organic solvents and the different methods for extraction and isolation of the PAC-fraction from foodstuffs are reviewed. The methodologies used for the separation, identification and quantitative determination also are briefly considered.

Chromatography↗
PubMed1982

Capillary column gas chromatography of environmental polycyclic aromatic compounds.

The methodologies are described for isolating clean fractions of polycyclic aromatic compounds from diverse environmental samples such as air particulate matter, sediments, and fish tissue. The common step in all procedures is the separation of the polycyclic aromatic compound fraction into well-defined chemical classes by adsorption chromatography on an alumina column. These procedures greatly facilitate the detailed characterization of the polycyclic aromatic hydrocarbons, sulfur heterocycles, and nitrogen heterocycles by capillary column gas chromatography.

Air Pollutants↗
PubMed1987

Mutagenicity of chlorinated polycyclic aromatic compounds.

The catalytic chlorination of polycyclic aromatic hydrocarbons leads to the formation of complex mixtures of isomers analogous to those found in fly ash samples of an incineration plant for radioactive waste. Therefore chlorination mixtures of chrysene, pyrene, and fluoranthene were analyzed and characterized by gas chromatography-mass spectrometry. Determination of the exact position of each chlorosubstituent within the molecule was not possible either by mass spectrometry or by comparison with well-defined methyl analogs. The toxic as well as mutagenic effects of such mixtures of isomers was compared with those of their parent hydrocarbons in the microtiter fluctuation test using Salmonella typhimurium TA 98 and TA 100 in a concentration range of 0.5 to 5.0 microgram/ml. No toxic effect could be observed, but the chlorinated products in contrast to their parent compounds were found to be strong mutagens to the S. typhimurium test strains and showed a positive response even without enzymatic activation. Frameshift mutations as well as base pair alterations were detected.

Animals↗
PubMed1986

Biotransformation of polycyclic aromatic compounds by fungi.

Incubations of several polycyclic aromatic hydrocarbons (PAHs) and heteroaromatic compounds with a series of common micro-organisms have been performed. The PAHs were not metabolized by any of the fungi studied. The sulphur-containing heterocyclic aromatic compounds dibenzothiophene, thioxanthone and thiochromanone were oxidized at sulphur by C. elegans. Other fungi are capable of oxidation at the sulphur atom of dibenzothiophene and thioxanthone. C-1 and C-3 methyl substituted thioxanthones are hydroxylated at the methyl group by C. elegans.

Biotransformation↗
PubMedDate not supplied

Mutagenicity of polycyclic aromatic compounds (PAC) identified in source emissions and ambient air.

Several polycyclic aromatic compounds (PAC) including nitrated and oxygenated derivatives of polycyclic aromatic hydrocarbons (PAH) were tested for mutagenic activity in the Salmonella/microsome assay. Among the compounds tested the isomer mix of nitro-1-hydroxypyrenes showed the highest direct mutagenic response in both the Salmonella strain TA98 and TA100 (1251 revertants/micrograms and 463 revertants/micrograms, respectively). The direct-acting mutagenicity of the nitro-1-hydroxypyrene isomer mix was dependent upon reduction of the nitro function as evidenced by the decrease in activity observed with the nitroreductase-deficient and arylhydroxylamine esterifying-deficient tester strains. The oxygenated derivatives of PAH containing aldehyde or keto groups showed weak or no mutagenic responses. In most cases addition of S9 was essential for any mutagenic activity and the strain TA100 was more sensitive than the strain TA98. Within this group, 7H-dibenzo[c,g]fluoren-7-one showed the highest mutagenic effect; 7 and 22 revertants/micrograms using the strains TA98 and TA100, respectively.

Air Pollutants↗
PubMed2002

Relative sensitivity of three terrestrial invertebrate tests to polycyclic aromatic compounds.

In a project investigating the ecotoxicity of polycyclic aromatic compounds (PACs), we have previously reported on the sublethal toxicity of eight PACs to springtails (Folsomia fimetaria) and enchytraeids (Enchytraeus crypticus). The model substances included four polycyclic aromatic hydrocarbons (PAHs) and four N-S-O-heterocyclics. Here, new data are presented on the effects of PACs on the survival and growth of the earthworm Eisenia veneta, showing that, in general, earthworm growth was reduced at PAC concentrations above 25 mg/kg soil dry weight. The E. veneta tests were performed using the same soil type and very similar test conditions as for the F. fimetaria and E. crypticus tests, thus providing a good opportunity to compare the sensitivity of these three organisms. Species sensitivity was examined using the 50% reduction in survival (LC50 values) and no-observable-effect concentrations (NOEC values) for growth or reproduction as endpoints. The difference between the least and most sensitive species was generally much larger for LC50 values as compared to the NOEC values, suggesting a higher degree of uncertainty when extrapolating from one species to another for the LC50 data. For the NOEC data, relatively small differences in sensitivity was observed, but as a rather consistent pattern, F. fimetaria was the most sensitive and E. crypticus the least sensitive species. However, one substance (acridine) showed specific toxicity toward E. veneta, which was more sensitive than the two other species by more than one order of magnitude.

Animals↗