Identification of polycyclic aromatic hydrocarbons and methoxylated phenols in wood smoke emitted during production of charcoal

More than 130 organic substances in dichloromethane-methanol (4: 1) extracts of particulate matter and the gaseous phase from wood burning for the production of charcoal have been identified by capillary gas chromatography coupled with low-resolution mass spectrometry (GC-MS), use of GC retention indices, and comparison with authentic standards. Many of the substances identified are methoxyphenols (derivatives of syringol and guaiacol), polycyclic aromatic hydrocarbons (PAH), oxidized PAH (oxy-PAH), and levoglucosan, the last being a monosoccharide derivative from the thermal breakdown of cellulose. The amount of unsubstituted PAH was greater than that of methyl- and dimethyl-substituted homologs.

Polycyclic aromatic hydrocarbons and other selected organic compounds in ambient air of Campo Grande City, Brazil

Fourteen samples of particulate matter and semi-volatile organic compounds were collected during 6 months in the city of Campo Grande, South Mato Grosso State, Brazil. Particle-bound polycyclic aromatic hydrocarbons (PAHs) were collected on Fluoropore PTFE filters and gas-phase PAHs were collected into sorbent tubes with XAD-2 resin. Both types of samples were extracted with a dichloromethane/methanol mixture (4:1 v/v), then the extracts were subjected to gas chromatography-mass spectrometry (GC-MS) analysis. PAHs, oxidized PAH (oxy-PAHs), phenols and methoxyphenols were identified by use of GC retention indices and MS files. The average value obtained for the sum of 15 PAHs was 21.05 ng m(-3) (range: 8.94-62.5 ng m(-3)). The presence of specific tracers and calculations of characteristic ratios (e.g. [Phe]/[Phe] + [Ant]) were used to identify the sources of the emissions of PAHs in the atmospheric samples. Levoglucosan (the anhydride of beta-glucose), retene (1-methyl-7-isopropylphenanthrene) and methoxyphenols (derivatives of syringol and guaiacol) and tracers for wood burning were identified. This study demonstrates that biomass burning from the rural zone is the main source of PAHs and emissions of other substances in the investigated site of Campo Grande. (c) 2004 Elsevier Ltd. All rights reserved.

Electrochemical reduction of aromatic sulfinic acids in dimethylsulfoxide

The electrochemical reduction of benzenesulfinic, p-toluenesulfinic, and p-nitrobenzenesulfinic acids was studied in dimethylsulfoxide solutions. From cyclic voltammetry experiments, a chemical reaction following the first electron transfer was detected during the reduction process. A cyclic voltammetry technique using ultramicroelectrodes has provided kinetic parameters for the electron-transfer steps, from which it was possible to observe the influence of the ring substituent on the electrochemical reduction. The mechanism of the electroreduction of aromatic sulfinic acids in dimethylsulfoxide depends upon the nucleophilic attack of the radical anion produced on the starting compound during the reduction processes.

A natural combinatorial chemistry strategy in acylpolyamine toxins from Nephilinae orb-web spiders

The present study shows how nature combined a small number of chemical building blocks to synthesize the acylpolyamine toxins in the venoms of Nephilinae orb-web spiders. Considering these structures in four parts, it was possible to rationalize a way to represent the natural combinatorial chemistry involved in the synthesis of these toxins: an aromatic moiety is connected through a linker amino acid to a polyamine chain, which in turn may be connected to an optional tail. The polyamine chains were classified into seven subtypes (from A to G) depending on the way the small chemical blocks are combined. These polyamine chains may be connected to one of the three possible chromophore moieties: 2,4-dihydroxyphenyl acetic acid, or 4-hydroxyindole acetic acid, or even with the indole acetic group. The connectivity between the aryl moiety and the polyamine chain is usually made through an asparagine residue; optionally a tail may be attached to the polyamine chain; nine different types of tails were identified among the 72 known acylpolyamine toxin structures. The combinations of three chromophores, two types of amino acid linkers, seven sub-types of polyamine backbone, and nine options of tails results in 378 different structural possibilities. However, we detected only 91 different toxin structures, which may represent the most successful structural trials in terms of efficiency of prey paralysis/death.

Identification of polycyclic aromatic hydrocarbons in sugar cane soot by gas chromatography mass spectrometry

Fly soot samples collected in the sugar cane fields after the process of burning were extracted in a Soxhlet apparatus (methylene chloride:methanol 4:1). The extracts were fractionated on silica gel Sep-Pak cartridges into three fractions. A gas chromatographic-mass spectrometric study of the fly soot extracts allowed the identification of the PAH with mutagenic and carcinogenic properties. Large amounts of aliphatic hydrocarbons, fatty acid esters and some PAHs were identified by GCMS in full scan mode. GC-MS in the selective ion monitoring mode (SIM) was suitable for the determination of many PAHs, which are often present in the burnt biomass. 31 PAHs and 7 thiophens derivatives were identified. The presence of these compounds should be regarded as a caution to workers and the general population to avoid exposure to the fly soot.

Aromatic compounds produced by Periconia atropurpurea, an endophytic fungus associated with Xylopia aromatica

6,8-Dimethoxy-3-(2'-oxo-propyl)-coumarin (1) and 2,4-dihydroxy-6-[(1'E,3'E)-penta-1', 3'-dienyl]-benzaldehyde (2), in addition to the known compound periconicin B (3), were isolated from the ethyl acetate extract of Periconia atropurpurea, an endophytic fungus obtained from the leaves of Xylopia aromatica, a native plant of the Brazilian Cerrado. Their chemical structures were assigned based on analyses of MS, 1D and 2D-NMR spectroscopic experiments. Biological analyses were performed using two mammalian cell lines, human cervix carcinoma (HeLa) and Chinese hamster ovary (CHO). The results showed that compound I had no effect when compared to the control group, which was treated with the vehicle (DMSO). Compound 2 was able to induce a slight increase in cell proliferation of HeLa (37% of increase) and CHO (38% of increase) cell lines. Analysis of compound 3 showed that it has potent cytotoxic activity against both cell lines, with an IC50 of 8.0 mu M. Biological analyses using the phytopathogenic fungi Cladosporium sphaerospermum and C. cladosporioides revealed that also 2 showed potent antifungal activity compared to nystatin. (c) 2006 Elsevier Ltd. All rights reserved.

Analysis of aromatic amines in surface waters receiving wastewater from a textile industry by liquid chromatographic with electrochemical detection

A high performance liquid chromatography ( HPLC) method with electrochemical detection (ED) was developed for the determination of benzidine, 3,3-dimethylbenzidine, o-toluidine and 3,3-dichlorobenzidine in the wastewater of the textile industry. The aromatic amines were eluted on a reversed phase column Shimadzu Shimpack C-18 using acetonitrile + ammonium acetate (1 x 10(-4) mol L-1) at a ratio 46: 54 v/v as mobile phase, pumped at a flow rate of 1.0 mL min(-1). The electrochemical oxidation of the aromatic amines exhibits well-defined peaks at a potential range of +0.45 to +0.78 V on a glassy carbon electrode. Optimum working potentials for amperometric detection were from 0.70 V to +1.0 V vs. Ag/AgCl. Analytical curves for all the aromatic amines studied using the best experimental conditions present linear relationship from 1 x 10(-8) mol L-1 to 1.5 x 10(-5) mol L-1, r = 0.99965, n = 15. Detection limits of 4.5 nM (benzidine), 1.94 nM (o-toluidine), 7.69 nM (3,3-dimethylbenzidine), and 5.15 nM (3,3-dichlorobenzidine) were achieved, respectively. The detection limits were around 10 times lower than that verified for HPLC with ultra violet detection. The applicability of the method was demonstrated by the determination of benzidine in wastewater from the textile industry dealing with an azo dye processing plant.

Fast chromatographic determination of polycyclic aromatic hydrocarbons in aerosol samples from sugar cane burning

Sugar cane burning in Brazil causes remarkable amounts of organic compounds to be emitted amongst which the polycyclic aromatic hydrocarbons (PAHs) represent serious health hazards. Therefore, 24-h aerosol samples (< 10 mum aerodynamic diameter) were collected in Araraquara city (São Paulo state) during the harvest season using a Hi-Vol sampler. PAHs were recovered using an Accelerated Solvent Extractor and analyzed by low-pressure gas chromatography-ion trap mass spectrometry (LP-GC-IT-MS). The fully automated extraction process was performed in less than 25 min with a solvent consumption of approximately 20 ml. The use of a deactivated 0.6 m x 0. 10 mm i.d. restrictor coupled to a 10 m wide-bore analytical column allowed most of the 16 PAHs in EPA's priority list to be identified and quantified in only 13 min. Concentrations of PAHs in Nraraquara aerosols ranged between 0.5 and 8.6 ng m(-3). (C) 2003 Elsevier B.V. All rights reserved.

Dipole moments in Langmuir monolayers from aromatic carboxylic acids

The three-layer capacitor model proposed by Demchak and Fort [J. Colloid Interface Sci. 46 (1974) 191] is employed to relate measured surface potentials of Langmuir monolayers from a series of polyphenyl carboxylic acids to molecular dipole moments calculated using semiempirical quantum methods. The effective dielectric constant at the air/monolayer interface is 3.0 +/- 0.6, very close to that estimated for aliphatic compounds. Good agreement between theory and experiment is obtained by adopting a dielectric constant of 6.4 for the monolayer/water interface and a contribution from the water reorientation of -0.064 +/- 0.006 D, which shows that the parameters in the DF model are essentially the same as for aliphatic amphiphiles, such as esters, acids, alcohols and ethers. (C) 2000 Elsevier B.V. B.V. All rights reserved.

Aromatic antiepileptic drugs and mitochondrial toxicity: Effects on mitochondria isolated from rat liver

Idiosyncratic hepatotoxicity is a well-known complication associated with aromatic antiepileptic drugs (AAED), and it has been suggested to occur due to the accumulation of toxic arene oxide metabolites. Although there is clear evidence of the participation of an immune process, a direct toxic effect involving mitochondria dysfunction is also possible. The effects of AAED on mitochondrial function have not been studied yet. Therefore, we investigated, in vitro, the cytotoxic mechanism of carbamazepine (CB), phenytoin (PT) and phenobarbital (PB), unaltered and bioactivated, in the hepatic mitochondrial function. The murine hepatic microsomal system was used to produce the anticonvulsant metabolites. All the bioactivated drugs (CB-B, PB-B, PT-B) affected mitochondrial function causing decrease in state three respiration, RCR, ATP synthesis and membrane potential, increase in state four respiration as well as impairment of Ca(2+) uptake/release and inhibition of calcium-induced swelling. As an unaltered drug, only PB, was able to affect mitochondrial respiration (except state four respiration) ATP synthesis and membrane potential; however, Ca(2+) uptake/release as well as swelling induction were not affected. The potential to induce mitochondrial dysfunction was PT-B > PB-B > CB-B > PB. Results suggest the involvement of mitochondrial toxicity in the pathogenesis of AAED-induced hepatotoxicity. (C) 2008 Elsevier Ltd. All rights reserved.

Improving the Fluorescence Detectability of Polycyclic Aromatic Hydrocarbons for Evaluation of Workplace Environments of Cement Industries Processing Organic Residues

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structure of thrombin complexed with selective non-electrophilic inhibitors having cyclohexyl moieties at P1

The crystal structures of five new non-electrophilic β-strand-templated thrombin active-site inhibitors have been determined bound to the enzyme. Four co-crystallize with hirugen and inhibitor isomorphously to produce thrombin-hirugen crystals (monoclinic, space group C2), while one co-crystallizes in the hexagonal system, space group P65. A 1,4-substituted cyclohexyl moiety is conserved at the P1 position of all the inhibitors, along with a fused hetero-bicyclic five- and six-membered ring that occupies the P2 site. Amino, amidino and aminoimidazole groups are attached to the cyclohexyl ring for recognition at the S1 specificity site, while benzylsulfonyl and diphenyl groups enhance the binding at the S3 subsite. The cyclohexyl groups at the P1 positions of three of the inhibitors appear to be in the energetically favored chair conformation, while the imidazole-substituted cyclohexyl rings are in a boat conformation. Somewhat unexpectedly, the two cyclohexyl-aminoimidazole groups bind differently in the specificity site; the unique binding of one is heretofore unreported. The other inhibitors generally mimic arginyl binding at S1. This group of inhibitors combines the nonelectrophilicity and selectivity of DAPA-like compounds and the more optimal binding features of the S1-S3 sites of thrombin for peptidic molecules, which results in highly potent (binding constants 12 nM-16 pM, one being 1.1 μM) and selective (ranging from 140 to 20 000 times more selective compared with trypsin) inhibitors of thrombin. The binding modes of these novel inhibitors are correlated with their binding constants, as is their selectivity, in order to provide further insight for the design of therapeutic antithrombotic agents that inhibit thrombin directly at the active site.

Eucalyptus ESTs associated with resistance to herbicide inhibitors of aromatic and branched-chain amino acid synthesis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The acylpolyamines from spider venoms

Acylpolyamines are low molecular mass toxins occurring exclusively in the venoms from solitary wasps and some groups of spiders. Their chemical structures have been elucidated using hyphenated techniques of mass spectrometry, such as LC-MS and MS/MS, or through direct analysis with different types of NMR analyses. The chemical structures of the acylpolyamine toxins from the venoms of Nephilinae orb-web spiders appear to be organized into four parts based on the combinatorial way that the chemical building blocks are bound to each other. An aromatic moiety (part I) is connected through a linker amino acid (part II) to a polyamine chain (part III), which in turn may be connected to an optional tail (part IV). The polyamine chains were classified into seven subtypes according to the different combinations of chemical building blocks. These polyamine chains, in turn, are connected to one of three chromophore moieties: a 2,4-dihydroxyphenyl acetyl group, a 4-hydroxyindolyl acetyl group, or an indolyl acetyl group. They may be connected through an asparagine residue or sometimes through the dipeptide ornithyl asparagine. Also, nine different types of backbone tails may be attached to the polyamine chains. These toxins are noncompetitive blockers of ionotropic glutamate receptors with neuroprotective action against the neuronal death and antiepileptic effect. Thus, compounds of this class of spider venom toxin seem to represent interesting molecular models for the development of novel neuropharmaceutical drugs. © 2012 Elsevier B.V. All rights reserved.

Essential oils from medicinal and aromatic plants: A review of the gastroprotective and ulcer-healing activities

Gastric ulcer is an excoriated area of the gastric mucosa. It is among the predominant gastrointestinal chronic diseases. The essential oils represent an important part of the traditional pharmacopoeia in many countries and have been successfully used for gastroprotection and ulcer healing. Thus, this review presents the experimental activity of essential oils traditionally used in the gastric ulcer prevention and treatment, considering their families, part of the plant studied, bioassays, and their mechanisms of gastroprotection and ulcer healing, with the aim of stimulating novel studies in the search for a new phytomedicine to treat gastric diseases. © 2012 The Authors Fundamental and Clinical Pharmacology © 2012 Société Française de Pharmacologie et de Thérapeutique.