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PubMed1996

Separation of naphthalene and flavone derivatives by micellar electrokinetic chromatography with double- and triple-chain surfactants.

Three surfactants, p-bis(2-dodecyloxymethyl-3-oxa-6-sodiosulfonatohexyloxy)benz ene (BDSB) having two sulfonate groups and two lipophilic chains, disodium 10-dodecanoyl-5,15-bis(dodecyloxymethyl)-10-aza-4,7,13,16-tetra oxa-1,19-nonadecanedisulfonate (DDBTN) having two sulfonate groups and three lipophilic chains and disodium 4,11-bis(dodecyloxymethyl)-3,6,9,12-tetraoxa-1,14-tetrade canedionate (DBTT) having two carboxylate groups and two lipophilic chains, were used in micellar electrokinetic chromatography (MEKC). Eight naphthalene derivatives were baseline separated at 10 mM BDSB or 5 mM DBTT, and five flavone derivatives at 5 mM BDSB, DDBTN or DBTT. The elution order of the naphthalene derivatives in MEKC with BDSB was identical with that with DDBTN. However, this elution order was different from that found with DBTT. In the case of the flavone derivatives, BDSB, DDBTN and DBTT produced the identical elution order. These double- and triple-chain surfactants exhibited different selectivity when compared with widely used sodium dodecyl sulfate.

Electrophoresis, Capillary↗
PubMed2002

Naphthalene glucoside and other phenolics from the shoot and callus cultures of Drosophyllum lusitanicum.

The callus and, for the first time established, shoot cultures of Drosophyllum lusitanicum Link. (Droseraceae) yielded new naphthalene glucoside-5-hydroxy-4-methoxy-2-naphthalenecarboxylic acid 5-O-beta-glucoside (drosophylloside) and 5-hydroxy-4-methoxy-2-naphthalenecarboxylic acid methyl ester besides other phenolics like naphthalenes-5-hydroxy-4-methoxy-2-naphthalenecarboxylic acid (ancistronaphthoic acid B), hydroplumbagin 4-O-glucoside, naphthoquinones-plumbagin and 3-chloroplumbagin, C-glycosylflavones- vitexin, isovitexin, orientin and isoorientin. The pattern of phenolics found supports affinity of Drosophyllum to the families-Droseraceae, Ancistrocladaceae and Dioncophyllaceae.

Droseraceae↗
PubMed2002

Development of a kinetic basis for bioavailability of sorbed naphthalene in soil slurries.

The degradation of naphthalene in soil-slurry systems was studied using four different organisms and two soils. Organisms with zero-order, first-order, and Michaelis-Menten rates were selected. The soils had substantially different sorption distribution coefficients. Sorption and desorption was evaluated in abiotic soil-slurry systems. The desorption process was described by a model that accounts for equilibrium, rate-limited and non-desorbing sites. Biodegradation parameters were measured in soil-extract solutions. Bioavailability assays, inoculated soil slurries, were conducted and both liquid- and sorbed-phase naphthalene concentrations were measured over time. For the less sorptive soil, the results could be explained by sequential desorption and degradation processes. For the other soil, enhanced degradation was clearly observed for the organisms with first-order and Michaelis-Menten rates. Several explanations are explored for these observations including direct sorbed-phase degradation and the development of elevated substrate concentrations at the organism/sorbent interface. No enhancement was found for the organism with zero-order kinetics.

Biological Availability↗
PubMed2000

Ground discarded tires remove naphthalene, toluene, and mercury from water.

Ground discarded tires adsorb naphthalene, toluene, and mercury ions (Hg2+) from aqueous solutions. Their sorption properties and kinetics were determined by batch equilibration techniques at 20 degrees C. The isotherms were linear for naphthalene and toluene and their sorption coefficients were about 1340 and 255 (ml/g), respectively. Sorption of the organic compounds by the ground rubber particles was relatively fast (within 30 min). However, the mercury isotherms were non-linear, and its sorption was slow as compared to the sorption of the organics. The rubber particles had a strong affinity for Hg2+. These results show that ground discarded tires are effective in removing organic compounds and Hg2+ from wastewater and other contaminated environments. In addition it would be a useful, environmentally friendly use of discarded tires (one tire per year per capita is discarded in the United States).

Adsorption↗
PubMed2001

Correlation of polychlorinated naphthalenes with polychlorinated dibenzofurans formed from waste incineration.

Isomer composition of polychlorinated naphthalenes (PCNs) was measured for municipal waste incinerator fly ash samples and for emission samples produced from soot and copper-deposit experiments conducted at the United States Environmental Protection Agency (US-EPA). Two types of PCN isomer patterns were identified. One pattern contained specific PCN isomers in which chlorine atoms are substituted as if the peri(alpha-) position were dechlorinated from the higher chlorinated PCNs one by one. In another pattern, the isomers had a tendency for the chlorine atoms to assume successive positions on the naphthalene ring, which may be caused by specifically oriented chlorination. Some of these isomers increased, together with several polychlorinated dibenzofuran (PCDF) and a few polychlorinated dibenzo-p-dioxin (PCDD) isomers. The ratios between some specific PCN, PCDF, and PCDD isomers measured for the fly ash samples agree with those obtained from the soot and copper-deposit experiments. The observations suggest that these isomers were formed possibly from de novo synthesis utilizing the carbon structure contained in soot under the catalytic effect of a copper compound. Typical isomers for PCNs and PCDFs produced from incineration emissions were identified.

Air Pollutants↗
PubMed2002

Effects of atmospheric exposure to naphthalene on xenobiotic-metabolising enzymes in the snail Helix aspersa.

Polycyclic aromatic hydrocarbons are xenobiotics whose elevated toxicity for living organisms requires to efficiently monitor air pollution, either by evaluating their levels in the environment, or by assessing their biological impacts on sentinel organisms. We investigated the effects of naphthalene exposure on some xenobiotic-metabolising enzyme activities in three organs of Helix aspersa. Particular activities depending on cytochrome P450 (ethoxyresorufin O-deethylase, EROD; ethoxycoumarin O-deethylase, ECOD; pentoxyresorufin O-dealkylase, PROD) and associated with glutathione (glutathione S-transferase, GST; glutathione peroxidase, GPX; glutathione reductase, GR) were assessed. In control animals, the P450-dependent specific activities were distributed according to the range kidney > digestive gland > mantle cavity forming tissues (MCFT). Neither ECOD nor PROD activities could be detected in MCFT. In the two other organs, the major phase I activities were due to ECOD, the level of PROD being very low or null. The glutathione-associated activities showed comparable levels in the three organs, except GPX activity that was higher in the digestive gland. Naphthalene (NAP) exposure did not affect any activity in MCFT, but it significantly decreased EROD and ECOD activities in the kidney as opposed to their increase in the digestive gland, whereas PROD activities were not influenced by the treatment. Glutathione-dependent activities were not significantly affected by NAP exposure, except for GPX which activity diminished in the digestive gland. This study demonstrates that complex detoxification pathways should exist in Helix aspersa as in mammals and that they could be used as potential biomarkers of NAP exposure.

Animals↗
PubMed2003

Estimation of selected physicochemical properties for methylated naphthalene compounds.

Liquid aqueous solubility (S(w,L)), octanol/water partition coefficients (K(ow)), liquid vapor pressure (P(v,L)), and Henry's law constants (H(c)) were estimated for 20 methylated naphthalenes ranging from monomethyl to tetramethylnaphthalenes. Chromatographic methods were used for the estimation. Chromatographic retention measurements were conducted for 11 reference compounds and regressions were fit between the retention indices and the physicochemical properties. HPLC octadecylsilyl column with acetonitrile/water eluent was used for the estimation of S(w,L) and K(ow). Two GC columns, HP5-MS and a more hydrophobic HP-1, were tested for the estimation of P(v,L). Measured retention indices for the methylated naphthalenes were entered to the regression equations to calculate the physicochemical properties for these compounds. Literature values, where available, were used to validate the calculated values. The method accurately estimated the physicochemical properties. Estimated S(w,L) and P(v,L) decreased with the number of methyl groups. K(ow) increased with the number of methyl groups. There was no obvious relation between H(c) and the number of methyl groups. Log S(w,L) ranged from 0.885 for 1,2,5,6-tetramethylnaphthalene to 2.269 for 1-methylnaphthalene (mmol/m(3)). Log K(ow) varied from 3.89 for 1-methylnaphthalene to 4.95 for 1,2,5,6-tetramethylnaphthalene. Log P(v,L) ranged from -0.983 for 1,2,5,6-tetramethylnaphthalene to 0.789 for 2-methylnaphthalene (Pa). Log H(c) varied from 1.03 for 1,4,5-trimethylnaphthalene to 1.73 for 2,6-dimethylnaphthalene (Pa m(3)/mol). There were no apparent effects of GC column hydrophobicity on the accuracy of the results. Estimation of S(w,L) and K(ow) based on GC retention indices was not as accurate as with HPLC. Comparison of the estimated values with values predicted by EPIWIN indicated that EPIWIN is useful in giving order-of-magnitude prediction of physicochemical properties.

Chemical Phenomena↗
PubMed2000

Partitioning of naphthalene to gemini surfactant-treated alumina.

Partitioning of naphthalene to anionic surfactants adsorbed on alumina in the aqueous phase was studied for immobilization of the contaminant in the subsurface. Three anionic surfactants with different molecular structures were used: a conventional (sodium dodecylbenzene sulfonate, SDDBS), a gemini (dialkylated disulfonated diphenyl oxide with alkyl chain length of 12, DADS-C12), and a dianionic (monoalkylated disulfonated diphenyl oxide with alkyl chain length of 12, MADS-C12). Sorption of the surfactants onto alumina was studied in a series of batch experiments and the effectiveness of the adsorbed surfactants onto aluminum oxide as a sorptive phase for naphthalene was compared.

Adsorption↗
PubMedDate not supplied

Synthesis and preliminary pharmacological results on new naphthalene derivatives as 5-HT(4) receptor ligands.

The indole derivative GR 113808 is currently used as the reference ligand for labelling the 5-HT(4) serotoninergic receptors. Previous works in our laboratories established the bioisosteric equivalency of the indole heterocycle and naphthalene in a series of melatonin receptor ligands. Based on this knowledge we designed new analogues of GR 113808 by introducing two bioisosteric modifications: firstly, the indole ring was replaced by a naphthalene one and secondly, the ester linkage was replaced by an amide group. Compound 8 emerged within this novel series as it displayed high and selective affinity at 5-HT(4) receptors (Ki 5-HT(4) = 6 nM, Ki 5-HT(3) = 100 nM, Ki values at other 5-HT receptors were higher than 1000 nM). Compound 8 is currently undergoing further pharmacological evaluation.

Indoles↗
PubMed2003

Polychlorinated naphthalenes in sediments from the industrial region of Bitterfeld.

Bitterfeld (Germany) was a major site of chemical production in the former German Democratic Republic with chloralkali electrolysis as the basic process. Effluents were dumped via the creek Spittelwasser into the rivers Mulde and Elbe. Despite the fact that the chloralkali industry is known as a possible source of polychlorinated naphthalenes (PCNs), to date no data about PCN pollution in the region of Bitterfeld and downstream regions are available. Therefore, sediments of the creek Spittelwasser were isomer-specifically analysed for penta-, hexa- and heptachlorinated naphthalenes using GC/MS. Concentrations of 880, 543 and 1120 ng/g dry weight were found, respectively. The isomer pattern suggests chloralkali industry as the major source of PCN contamination. Because of their toxicological relevance we suggest to include PCNs into monitoring and risk assessment programs of the rivers Mulde and Elbe downstream of Bitterfeld.

Chemical Industry↗
PubMed1999

Thermogravimetric study of thermal decontamination of soils polluted by hexachlorobenzene, 4-chlorobiphenyl, naphthalene, or n-decane.

To determine decontamination behavior as affected by temperature, shallow beds of a clay-rich, a calcerous, and a sedimentary soil, artificially polluted with hexachlorobenzene, 4-chlorobiphenyl, naphthalene, or n-decane, were separately heated at 5 degrees C min-1 in a thermogravimetric analyzer. Temperatures for deep cleaning of the calcerous and the sedimentary soil increased with increasing boiling point (bp) of the aromatic contaminants, but removal efficiencies still approached 100% well below the bp. Decontamination rates were therefore modelled according to a pollutant evaporation-diffusion transport model. For the calcerous and sedimentary soils, this model reasonably correlated removal of roughly the first 2/3 of the naphthalene, but gave only fair predictions for hexachlorobenzene and 4-chlorobiphenyl. It was necessary to heat the clay soil above the aromatics bp to achieve high decontamination efficiencies. Weight loss data imply that for temperatures from near ambient to as much as 150 degrees C, interactions of each aromatic with the clay soil, or its decomposition products, result in lower net volatilization of the contaminated vs. neat clay. A similar effect was observed in heating calcerous soil polluted with hexachlorobenzene from near ambient to about 140 degrees C. Decontamination mechanisms remain to be established, although the higher temperatures needed to remove aromatics from the clay may reflect a more prominent role for surface desorption than evaporation. This would be consistent with our estimates that the clay can accommodate all of the initial pollutant loadings within a single surface monolayer, whereas the calcerous and sedimentary soils cannot.

Alkanes↗
PubMed1999

Influence of water on the supercritical fluid extraction of naphthalene from soil.

Supercritical fluid extraction (SFE) is an innovative soil remediation technology. To aid system evaluation and design, thermodynamic and kinetic parameters have been measured using a naphthalene contaminated, loamy sand at various water contents. The experimental results show that supercritical carbon dioxide can easily extract naphthalene from soil when the water content is below 10%. At low water contents, mass transfer is rapid and the equilibrium partition coefficient is independent of the soil's water content. However, the overall mass transfer coefficient, (kova), decreases by at least a factor of 200 as the water content increases from 10 to 20%.

Carbon Dioxide↗
PubMed2002

Structural assignment of 2,6- and 2,7-disubstituted naphthalenes and prediction of (13)C nuclear magnetic resonance chemical shifts: applications of topology and two-dimensional NMR spectroscopy.

Unambiguous assignments of monocarboxymethylnapthalenes isolated as oxidation products of dimethylnaphthalenes by Pseudomonas putida, a bacterial strain, were made using two-dimensional nuclear Overhauser enhancement correlation spectroscopy (NOESEY). The two-dimensional long-range heteronuclear correlation NMR technique was also utilized for the assignment of quaternary carbons in the naphthalene system. In addition, we describe methods for prediction of 13C NMR chemical shifts of 2,6- and 2,7-disubstituted naphthalenes using topological approach. The method involves computation of molecular descriptors from topological representation of molecule, namely Wiener (W) and Szeged (Sz) indices. The results have shown that W and Sz indices can be successfully used for predicting 13C NMR chemical shifts and that Sigma13Cn can be used as a molecular property which in turn can be modeled by both W and Sz indices successfully.

Algorithms↗
PubMed1998

Synthesis and structure-activity relationships of novel naphthalenic and bioisosteric related amidic derivatives as melatonin receptor ligands.

A previous paper reported the synthesis of melatonin receptor ligands. In order to complete the structure-activity relationships and to obtain antagonists to the melatonin receptor, a new series of naphthalenic analogues of melatonin have been synthesized. Modifications include deletion of the 7-methoxy group, replacement of the ethylene moiety, replacement of the amidic function by bioisosteres, and replacement of the naphthalenic nucleus by other bicyclic rings. Almost all the structural modifications lead to decreased affinity for the melatonin receptor. However, the N-n propyl urea derivative (27) is a very potent ligand at this receptor (pKi = 14.3). Most interestingly deletion of the methoxy group resulted in the first antagonist in this series. This molecule, compound 12, or N-[2-(1-naphthyl)-ethyl]cyclobutyl carboxamide has been selected for preclinical development.

Amides↗
PubMed1998

Structure of an aromatic-ring-hydroxylating dioxygenase-naphthalene 1,2-dioxygenase.

BACKGROUND: Pseudomonas sp. NCIB 9816-4 utilizes a multicomponent enzyme system to oxidize naphthalene to (+)-cis-(1R,2S)-dihydroxy-1,2-dihydronaphthalene. The enzyme component catalyzing this reaction, naphthalene 1,2-dioxygenase (NDO), belongs to a family of aromatic-ring-hydroxylating dioxygenases that oxidize aromatic hydrocarbons and related compounds to cis-arene diols. These enzymes utilize a mononuclear non-heme iron center to catalyze the addition of dioxygen to their respective substrates. The present study was conducted to provide essential structural information necessary for elucidating the mechanism of action of NDO. RESULTS: The three-dimensional structure of NDO has been determined at 2.25 A resolution. The molecule is an alpha 3 beta 3 hexamer. The alpha subunit has a beta-sheet domain that contains a Rieske [2Fe-2S] center and a catalytic domain that has a novel fold dominated by an antiparallel nine-stranded beta-pleated sheet against which helices pack. The active site contains a non-heme ferrous ion coordinated by His208, His213, Asp362 (bidentate) and a water molecule. Asn201 is positioned further away, 3.75 A, at the missing axial position of an octahedron. In the Rieske [2Fe-2S] center, one iron is coordinated by Cys81 and Cys101 and the other by His83 and His104. CONCLUSIONS: The domain structure and iron coordination of the Rieske domain is very similar to that of the cytochrome bc1 domain. The active-site iron center of one of the alpha subunits is directly connected by hydrogen bonds through a single amino acid, Asp205, to the Rieske [2Fe-2S] center in a neighboring alpha subunit. This is likely to be the main route for electron transfer.

Amino Acid Sequence↗
PubMed1997

Genotoxicity induced in human lymphoblasts by atmospheric reaction products of naphthalene and phenanthrene.

The genotoxic risks from exposure to polycyclic aromatic hydrocarbons (PAH) have long been recognized. Less well understood are the potential genotoxic risks of the atmospheric reaction products of this class of compounds. In this investigation, we have utilized several human cell genotoxicity assays to evaluate naphthalene, phenanthrene, and their atmospheric reaction products 1-nitronaphthalene, 2-nitronaphthalene, 1-hydroxy-2-nitronaphthalene, 2-hydroxy-1-nitronaphthalene, 1,4-naphthoquinone and 2-nitrodibenzopyranone. In addition, reaction products of naphthalene were generated in a 6700-1 Teflon environmental chamber, collected on a solid adsorbent, extracted and fractionated by normal-phase HPLC. Individual fractions were then analyzed using GC-MS, and tested for genotoxicity. Genotoxicity was determined using the human B-lymphoblastoid cell line, MCL-5, which expresses several transfected P450 and epoxide hydrolase genes. Mutagenicity was evaluated at both the heterozygous tk locus and the hemizygous hprt locus, permitting detection of both intragenic and chromosomal scale mutational events. Test compounds were also screened using the CREST modified micronucleus assay. Genotoxicity results indicate that 2-nitronaphthalene and 2-nitrodibenzopyranone possess greater mutagenic potency than their parent compounds, and interestingly, both compounds induced significant increases in mutation frequency at tk but not hprt. These results suggest a mechanistic difference in human cell response as compared to bacteria, where both compounds were previously shown to induce point mutations in the Salmonella reversion assay. The genotoxicity of 2-nitronaphthalene and 2-nitrodibenzopyranone in human cells, together with their high concentrations in ambient air relative to nitro-PAH directly emitted from combustion sources, emphasizes the need to consider atmospheric reaction products of PAH in genotoxicity assessments.

Air Pollutants↗
PubMed2001

Determination of photophysical rate constants for the non-protected fluid room temperature phosphorescence of several naphthalene derivatives.

The determination of kinetic parameters for luminescence processes is very important in understanding the phosphorescence process and the mechanisms of the heavy atom effect (HAE). In our previous work, we reported that room temperature phosphorescence (RTP) emission of many naphthalene derivatives can be induced directly from their aqueous solution without using any kind of protective medium, and the name Non-Protected Fluid Room Temperature Phosphorescence (NP-RTP) is suggested for this new type of RTP emission. In order to further understand this kind of luminescence phenomenon, the influence of heavy atom perturber (HAP) concentration on RTP lifetime of several naphthalene derivatives was studied in detail in this paper. The possibility of determination of photophysical parameters for emission of NP-RTP was explored based on the definition on the phosphorescence lifetime and the relation with the concentration of HAP in this paper. A static Stern-Volmer equation for phosphorescence was derived and the luminescence kinetic parameters were calculated. The results obtained by two different ways proved that photophysical parameters for RTP emission can be determined based on the changes of the RTP lifetime.

Kinetics↗
PubMed1999

Liquid chromatography/mass spectrometry analysis of mixtures of rhamnolipids produced by Pseudomonas aeruginosa strain 57RP grown on mannitol or naphthalene.

Liquid chromatography/mass spectrometry using electrospray ionisation was used to analyse rhamnolipids produced by a Pseudomonas aeruginosa strain with mannitol or naphthalene as carbon source. Identification and quantification of 28 different rhamnolipid congeners was accomplished using a reverse-phase C(18) column and a 30 min chromatographic run. Isomeric rhamnolipids that were not chromatographically resolved could be identified by interpretation of their mass spectra and their relative proportions estimated. The most abundant rhamnolipid produced on mannitol contained two rhamnoses and two 3-hydroxydecanoic acid groups. The most abundant rhamnolipid produced from naphthalene contained two rhamnoses and one 3-hydroxydecanoic acid group.

Chromatography, Liquid↗