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At least 55 records · Page 3Linked to original sources
PubMed2006

Blue rayon-anchored technique/Salmonella microsome microsuspension assay as a tool to monitor for genotoxic polycyclic compounds in Santos estuary.

The most important harbor of Brazil is located in Santos Estuary. In the 1970s, this area was one of the major examples of coastal degradation and although the quality of the environment has improved, the sediment is still contaminated with polycyclic aromatic hydrocarbons (PAHs) and mutagenic activity. Because of sediment dredging and consequently contaminants resuspension, it is useful to have reliable methods to monitor the water quality. Considering that blue rayon (BR) has been successfully used in evaluation of mutagenicity and PAHs content the objective of this work was to verify the applicability and adapt the methodology to monitor the water for mutagenic activity using the BR associated with the Salmonella assay. Analysis of three sites with different levels of contamination was performed using a modification of the BR hanging method denominated in this work BR anchored technique. The microsuspension protocol of the Salmonella/microsome assay was employed with the strain YG1041. The water from the site 1 the most contaminated and under influence of the steel mill discharge presented the highest potency reaching 36,000 revertants/g of BR with S9. Sites 2 and 3 showed less mutagenicity than site 1 with values approximately 1000 revertants/g of BR. We conclude that the BR anchored technique associated with Salmonella assay using YG1041 is a reliable alternative to monitor estuarine waters, especially in regions where sediment resuspension or acute pollution episodes can occur.

Animals↗
PubMed1978

Electrochemical properties of polycyclic compounds studied by the polarographic method in anhydrous systems. VI. The influence of proton-donor on reduction of carcinogenic aromatic hydrocarbons in anhydrous environment.

The authors have studied the electrochemical behaviour of a series of carcinogenic and inactive aromatic hydrocarbons in anhydrous environment in the presence of a proton-donor. As anhydrous environment the authors used water-free dimethylformamide and dimethylsulfoxide; as proton-donor phenol. Phenol gave rise to quantitative changes in the number of polarographic waves when the carcinogenic aromatic hydrocarbons were undergoing reduction. Between the two original waves there originated in the presence of phenol a new polarographic wave in these hydrocarbons. In inactive analogues of the investigated hydrocarbons no such effect of phenol has been ascertained. In their present study the authors discuss the potential mechanism of electroreduction of carcinogenic and inactive aromatic hydrocarbons in anhydrous environment in the presence of a proton-donor and compare the values of half-wave potentials of the investigated compounds measured in water-free dimethylformamide, dimethylformamide + phenol and in ethylenglycolmonomethylether.

Carcinogens↗
PubMed2002

In vitro antimicrobial activity of GSQ1530, a new heteroaromatic polycyclic compound.

GSQ1530 is a compound derived from a newly identified class of antibiotics referred to as heteroaromatic polycyclic (HARP) antibiotics. The aim of this study was to assess the in vitro antimicrobial activity of GSQ1530. By using an NCCLS broth microdilution assay, the activities of GSQ1530 and other antibiotics were coevaluated against 215 clinical isolates. The MICs at which 90% of isolates are inhibited (MIC(90)s) of GSQ1530 for methicillin-susceptible Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) were 2 and 4 micro g/ml, respectively. The MIC(90)s of GSQ1530 for the streptococci tested were 2 micro g/ml or less, regardless of their susceptibilities to other antibiotics. The MIC(90) of GSQ1530 for the enterococci tested (including vancomycin-resistant enterococci) was 4 micro g/ml. No cross-resistance was found between GSQ1530 and other known antibiotics. In a separate assay, GSQ1530 demonstrated excellent activity against vancomycin-intermediate-susceptible staphylococci (MIC(90), 1 micro g/ml). The minimal bactericidal concentration test was conducted with 73 clinical isolates; GSQ1530 was cidal against streptococci and staphylococci but static against enterococci. An in vitro killing kinetic study revealed a time-dependent profile, with at least a 3-log reduction of bacterial growth within 6 h after exposure to four times the MICs of GSQ1530 for both S. aureus and Streptococcus pneumoniae. The checkerboard study showed that GSQ1530 had a synergistic interaction with rifampin against MRSA. The test medium was found to have little effect on in vitro antimicrobial potency. The MICs of GSQ1530 for gram-positive cocci were 4- to 32-fold higher in the presence of serum proteins. GSQ1530 has high levels of plasma protein binding (91 and 89% for rat and human plasma, respectively). These preliminary results demonstrate that GSQ1530, a representative compound of our novel HARP antibiotics, has broad-spectrum activity against gram-positive bacteria. This novel class of antibacterial compounds is profiled in vivo to assess the therapeutic potential in humans. Ongoing in vivo studies will assess whether this class of molecules has promising in vivo efficacy and safety profiles.

Animals↗
PubMed1965

METABOLISM OF POLYCYCLIC COMPOUNDS. THE METABOLISM OF 7,12-DIMETHYLBENZ(ALPHA)ANTHRACENE BY RAT-LIVER HOMOGENATES.

1. The main products of the metabolism of 7,12-dimethylbenz[a]anthracene by rat-liver homogenates are the isomeric monohydroxymethyl derivatives. The syntheses of these compounds are described. 2. Two phenolic products and two dihydrodihydroxy compounds were formed, but none of these appeared to have been formed by hydroxylation at the ;K region'. There was little evidence for the formation of a glutathione conjugate of the hydrocarbon. 3. The monohydroxymethyl derivatives are products of the hydroxylation of the hydrocarbon in the ascorbic acid-Fe(2+)-oxygen model hydroxylating system.

Anthracenes↗
PubMed1965

METABOLISM OF POLYCYCLIC COMPOUNDS. THE METABOLISM OF 1,4-EPOXY-1,4-DIHYDRONAPHTHALENE IN RATS.

1. 1,4-Epoxy-1,4-dihydronaphthalene is converted by rats into 1,4:2,3-diepoxy-1,2,3,4-tetrahydronaphthalene, which was isolated from the urine. The synthesis of the diepoxide is described. 2. The monoepoxide also yielded a compound that is believed to be 1,4-dihydro-1,4-dihydroxynaphthalene, but no corresponding mercapturic acid was detected. A number of unidentified metabolites of the monoepoxide were detected that appear to arise by the hydroxylation of the diepoxide. 3. The monoepoxide is converted into the diepoxide by a rat-liver microsomal system. 4. 1,4-Epoxy-1,4-dihydronaphthalene does not appear to be an intermediate in naphthalene metabolism.

Chromatography↗
PubMed1978

Electrochemical properties of polycyclic compounds studied by the polarographic method in anhydrous systems. V. Oxidation potentials of carcinogenic hydrocarbons in acetonitrile.

The half-wave oxidation potentials of polycyclic carcinogenic hydrocarbons have been studied at the rotating platinum electrode in anhydrous acetonitrile with sodium perchlorate as the supporting electrolyte. The good agreement was obtained by the comparison of the carcinogenic activity of studied compounds with the values of the oxidation potentials. The values of the oxidation half-wave potentials were correlated also with the reduction potentials measured in acetonitrile and with the root xn of the Hückel secular equation for the highest bonding orbital.

Acetonitriles↗
PubMed1977

Electrochemical properties of polycyclic compounds studied by the polarographic method in anhydrous systems. IV. Polarographic study of carcinogenic and noncarcinogenic hydrocarbons in ethylenglycolmonomethylether.

An experiment was carried out to determine whether there is any correlation between the values of polarographic reduction potentials of polycyclic hydrocarbons and their carcinogenic activity. A comparison of half-wave potentials of polarographic wave I and II of pyrene benzologs revealed that the carcinogenic ones become reduced in ethylenglycolmonomethylether on a mercury dropping electrode at more positive potentials than the inactive benzo- and dibenzopyrenes. The discussion bears both on the reduction mechanism of the compounds and on the relationship between the half-wave potentials and the absorption electron spectra measured in the same solvent.

Benzopyrenes↗
PubMed2002

Synthesis of aza polycyclic compounds derived from pyrrolidine, indolizidine, and indole via intramolecular Diels-Alder cycloadditions of neutral 2-azadienes.

A method for the preparation of novel oxaza and diaza polycyclic 9-oxa-4-azaphenanthrene, 5H-pyrido[2,3-a]pyrrolizine, 5H,6H-pyrido[3,2-g]indolizine, and 5H,6H-indeno[2,1-a]indole is described, based on tandem reactions: aza-Wittig reaction of N-vinylic phosphazenes with functionalized aldehydes and an intramolecular aza-Diels-Alder reaction.

Journal Article↗
PubMed1998

Research on 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, Part 2.

Acid catalyzed cyclization reactions of both 3-alkyl- and 3-aryl-substituted N-(2,2-dialkoxyethyl)-3,4-dihydro-2H-1,4-benzothiazines (2) lead to 2,3-dihydro-pyrrolo[1,2,3-de]-1,4-benzothiazines (3). The pyrrolobenzothiazine structure was deduced on the basis of 2D 1H NMR-NOESY experiments and fully determined by X-ray data. Compounds 3a-c showed poor antibacterial activity. However, the 3-phenyl-N-(2,2-dimethoxyethyl)-3,4-dihydro-2H-1,4-benzothiazine (2b') showed antifungal activity against Aspergillus niger 16-fold greater than miconazole.

Animals↗