6-Alkyl-3,4-dihydro-2H-pyrans: Chemical Secretion Compounds in Neotropical Harvestmen

The defensive, secretions, of five neotropical) species of harvestmen, (Opiliones: Gonyleptidae) from the Brazilian Atlantic Forest were analyzed and chemically characterized by GC-MS and NMR Methods. Three of the species, Cobania picea, Roweria virescens, and Serracutisoma proximum, secrete a mixture of 2,3-dimethyl-1,4-benzoquinone and 2-ethyl-3methyl-1,4,4-benzoquinone. The secretions produced,by the Other two species Iporangaia pustulosa and Neosadocus maximus, contain 1-hepten-3-one, 5-methyl-1-hexen-3-one, and 1-(6-butyl-3,4-dihydro-2H-pyran-2-yl)pentanone. (1)as major components, as well as,2,3-dimethyl-1.,4-benzoquinone and 2-ethyl-3 methyl-1,4-benzoquinone as minor,constituents. The. dihydropyran 1-(6-butyl-3,4-dihydro-2H-pyran-2-yl)pentanone (1) is a new natural product, composed of two 1-hepten-3-one, subunits formally linked in a hetero-Diels-Alder reaction. The natural product was proven to be racemic, and its biogenetic origin is discussed.

The opportunistic fungal pathogen Scedosporium prolificans: Carbohydrate epitopes of its glycoproteins

Isolated from the mycelium, of Scedosporium prolificans were complex glycoproteins (RMP-Sp), with three structurally related components (HPSEC). RMP-Sp contained 35% protein and 62% carbohydrate with Rha, Ara, Man, Gal, Glc, and GlcNH(2) in a 18:1:24:8:6:5 molar ratio. Methylation analysis showed mainly nonreducing end- of Galp (13%), nonreducing end- (9%),2-O-(13%), and 3-O-subst. Rhap (7%), nonreducing end-(11%), 2-O-(10%), 3-O-(14%), and 2,6-di-O-subst. Manp units (13%). Mild reductive P-elimination of RMP-Sp gave alpha-L-Rhap-(1-->2)-alpha-L-Rhap-(1-->3)-alpha-L-Rhap-(1-->3)-alpha-D-Manp-(1-->2)-D-Man-ol, with Man-ol substituted at O-6 with beta-D-Galp units, a related pentasaccharide lacking beta-D-Galp units, and beta-D-Galp-(1-->6)-[alpha-D-Manp-(1-->2)]-D-Man-ol in a 16:3:1 w/w ratio. Traces of Man-ol and Rha-ol were detected. ESI-MS showed HexHex-o1 and HCX(3-6)Hex-ol components. Three rhamnosyl units were peeled off successively from the penta- and hexasaccharide by ESI-MS-MS. The carbohydrate epitopes of RMP-Sp differ from those of the glycoprotein of Pseudallescheria boydii, a related opportunistic pathogen. (C) 2007 Elsevier B.V. All rights reserved.

N-H...S=C hydrogen bond in O-alkyl N-methoxycarbonyl thiocarbamates, ROC(S)N(H)C(O)O)CH(3) (R = CH(3)(-), CH(3)CH(2)-)

Pure O-methyl N-methoxycarbonyl thiocarbamate CH(3)OC(S)N(H)C(O)OCH(3) (I) and O-ethyl N-methoxycarbonyl thiocarbamate, CH(3)CH(2)OC(S)N(H)C(O)OCH(3) (II), are quantitatively prepared by the addition reaction between the CH(3)OC(O)NCS and the corresponding alcohols. The compounds are characterized by multinuclear ((1)H and (13)C) and bi-dimensional ((13)C HSQC) NMR, GC-MS and FTIR spectroscopy techniques. Structural and conformational properties are analyzed using a combined approach involving crystallographic data, vibration spectra and theoretical calculations. The low-temperature (150 K) crystal structure of II was determined by X-ray diffraction methods. The substance crystallizes in the monoclinic space group P2(1)/n with a = 4.088(1)angstrom. b = 22.346(1)angstrom, c = 8.284(1)angstrom, beta = 100.687(3)degrees and Z = 4 molecules per unit cell. The conformation adopted by the thiocarbamate group -OC(S)N(H)- is syn (C=S double bond in synperiplanar orientation with respect to the N-H single bond), while the methoxycarbonyl C=O double bond is in antiperiplanar orientation with respect to the N-H bond. The non-H atoms in II are essentially coplanar and the molecules are arranged in the crystal lattice as centro-symmetric dimeric units held by N-H center dot center dot center dot S=C hydrogen bonds Id(N center dot center dot center dot S) = 3.387(1)angstrom, <(N-H center dot center dot center dot S) = 166.4(2)degrees]. Furthermore, the effect of the it electronic resonance in the structural and vibrational properties is also discussed. (C) 2009 Elsevier Ltd. All rights reserved.

Structural effects and hydrogen bonds on N,N `-di(methoxycarbonylsulfenyl)urea, [CH(3)OC(O)SNH](2)CO, studied by experimental and theoretical methods

Pure N,N`-di(methoxycarbonylsulfenyl)urea, [CH(3)OC(O)SNH](2)CO, is quantitatively prepared by the hydrolysis reaction of CH(3)OC(O)SNCO and characterized by (1)H NMR, GC-MS and FTIR spectroscopy techniques. Structural and conformational properties are analyzed using a combined approach with data obtained from X-ray diffraction, vibrational spectra and theoretical calculation methods. The IR and Raman spectra for normal and deuterated species are reported. The crystal structure of [CH(3)OC(O)SNH](2)CO was determined by X-ray diffraction methods. The substance crystallizes in the orthorhombic P2(1)2(1)2 space group with a = 9.524(2), b = 12.003(1), c = 4.481 (1) angstrom, and Z = 2 moieties in the unit cell. The molecule is sited on a twofold crystallographic axis (C(2)) parallel to c and shows the anti-anti conformation (S-N single bonds antiperiplanar with respect to the opposite C-N single bonds in sulfenyl-urea-sic group). Neighboring molecules are arranged in a chain motif that extends along the C(2)-axis and is held by bifurcated NH center dot center dot center dot O center dot center dot center dot HN intermolecular bonds. A local planar symmetry is observed in the crystal for the central -SN(H)C(O)N(H)S- skeleton. Experimental and calculated data allow to trace this structural feature to the occurrence of N-H center dot center dot center dot O=C hydrogen bonding interactions. Calculated vibrational and structural properties are in good agreement with the experimentally determined features. (C) 2008 Elsevier B.V. All rights reserved.

Isolation, chemical composition and anti-inflammatory activity of Copaifera langsdorffii desf. fruit peels essential oil according to successive hydrodistillations

In this study, the isolation and characterization of chemical composition of C. langsdorffii (copaiba) fruit peel volatile oil from Alfenas - MG was carried out according to successive hydrodistillations, likewise the anti-inflammatory activity was evaluated by rat paw edema model. The chemical composition of the oil was determined by GC-MS analysis. The major components were (E)-caryophyllene, germacrene B, 1,5-epoxysalvial-4(14)-ene, caryophyllene oxide and isospathulenol. The inflammatory process was inhibited in 39 +/- 6 % (p<0.05, Tukey-Kramer) by one sample of essential oil. The C. langsdorffii fruit peel is a rich source of essential oil (3.8% w/w), and due to potential industrial interest of its components this ecotype presents feasible crop seeking productivity and it could constitutes in a good alternative to the sustainable use of this specie.

Useful Strategies for Algal Volatile Analysis

The production of volatile organic compounds (VOC) by plants is well known. However, few scientific groups have studied VOC produced by green, brown and red algae. Headspace collection of volatiles and solid phase microextraction, as well as the traditional extraction by hydrodistillation combined with analytical chromatographic techniques (i.e., GC-MS), have significantly improved the investigation of VOC from plants and algae. The major volatile compounds found in seaweeds are hydrocarbons, terpenes, phenols, alcohols, aldehydes, ketones, esters, fatty acids and halogen or sulfur-containing compounds. This article presents an overview of VOC isolated from and identified in marine macro-algae. Focus is given to non-halogenated and non-sulfur volatile compounds, as well as strategies to analyze and identify algal VOC by GC-MS.

Composition and antifungal activity against Candida albicans, Candida parapsilosis, Candida krusei and Cryptococcus neoformans of essential oils from leaves of Piper and Peperomia species

This study was addressed to investigate the composition and antifungal activity of essential oils from leaves of Piperaceae species (Piper aduncum, Piper amalago, Piper cernuum, Piper diospyrifolium, Piper crassinervium, Piper gaudichaudianum, Piper solmsianum, Piper regnellii, Piper tuberculatum, Piper umbelata and Peperomia obtusifolia) against Candida albicans, C. parapsilosis, C. krusei and Cryptococcus neoformans. The essential oils from P. aduncum, P. gaudichaudianum and P. solmsianum showed the highest antifungal activity against Cryptococcus neoformans with the MIC of 62.5, 62.5 and 3.9 mg.mL-1, respectively. The oil from P. gaudichaudianum showed activity against C. krusei with MIC of 31.25 mg.mL-1.

Chemical Composition and Antimicrobial Activity of the Essential Oil from Rollinia sericea (REFr.) REFr. (Annonaceae) Leaves

The chemical composition of the essential oil of Rollinia sericea (R.E.Fr.) R.E.Fr. leaves was determined by GC and GC/MS analysis. The analysis revealed the presence mainly of sesquiterpenes: beta-elemene (10%), beta-caryophyllene (10.0%), bicyclogermacrene (9.1%), germacrene-D (8.2%), bicycloelemene (6.2%) and (Z)-nerolidol (5.3%). Rollinia sericea oil was able to inhibit the growth of both fungi Aspergillus niger (16404) and Candida albicans (ATCC 10231) as well as the Gram-positive bacterium Staphyloccocus aureus (ATCC 6538) but it was inactive against the Gram-negative bacteria Escherichia coli (ATCC 8739) and Pseudomonas aeruginosa (ATCC 9027).

Anti-inflammatory activity of essential oil from leaves of Myrciaria tenella and Calycorectes sellowianus

The GC-MS analysis revealed that the leaf essential oils of Myrciaria tenella (DC.) Berg and Calycorectes sellowianus O. Berg (Myrtaceae) were composed of 34 and 37 compounds, respectively. The main constituents of M. tenella oil were beta-caryophyllene (25.1%), and spathulenol (9.7%), while for C. sellowianus were guaiol (13.1%) and beta-caryophyllene (8.6%). The anti-inflammatory effect of both essential oils was investigated in vitro and in vivo. Both oils reduced significantly (p < 0.005) the treated neutrophils chemotaxis with 93% and 91% inhibition for M. tenella and C. sellowianus, respectively. However, in the systemic treatment with the essential oils (50 mg/kg p.o.) only the M. tenella oil was able to significantly reduce the carrageenan-induced paw edema with a similar effect to that observed for indomethacin (10 mg/kg), the positive control.

Chemical Composition and Antimicrobial Activities of the Essential Oil of Hypericum cordatum (Vell. Conc.) N. Robson (Hypericaceae)

The volatile Constituents of the fresh materials of Hypericum cordatum were isolated by hydrodistillation kind analyzed by CC and GC/MS. The leaves produced 0.04% of a yellowish essential oil and the flowers did not. The main components of the oil were myrcene (40.18%), alpha-pinene (16.40%), and limonene (12%). The antibacterial activities of the oil against Saccharomyces aureus and Escherichia coli and the anti-fungal activities of the oil against the fungi Cladosporium cladosporioides and C. sphaerospemum were evaluated. The oil showed an antibacterial activity against the bacteria S. aureus and anti-fungal activity against the two fungi.

Constituents of Leaves Essential Oil of Talauma ovata A. St.-Hil. (Magnoliaceae)

Tire volatile constituents of the fresh leaves of Talauma ovata (Magnoliaceae) were extracted by hydrodistillation and analyzed by GC and GC/MS. Twenty-seven compounds were identified representing 98.8% of the total oil. The oil from this species showed to be constituted by monoterpenes and sesquiterpenes in the same ratio. Among the monoterpenes, limonene (34.8%) and alpha-pinene (11.3%) were the main constituents, and beta-bisabolene (10.7%) was the major substance for the sesquiterpene fraction.

Essential Oil from Leaves and Stem Bark of Southeastern Drimys brasiliensis Miers (Winteraceae)

The chemical composition of essential oils obtained from fresh leaves and stem bark of Southeastern Brazilian native Drimys brasiliensis Miers were analyzed by GC and GC/MS and 37 compounds were identified. The oils from fresh leaves showed the presence of monoterpenes (53.9%) and sesquiterpenes (38.4%), with sabinene (9.5%), myrcene (10.5%), limonene (10.6%) and cyclocolorenone (16.0%) being the most abundant. The stern bark oil was characterized by predominance of sesquiterpenoids (87.6%) and the absence of monoterpenes, the main components being cyclocolorenone (28.3%) and spathuleneol (22.9%). A small amount of phenylpropanes (6.8-6.9%) was also detected in both oil samples.

Biotransformation of alpha-Bromoacetophenones by the Marine Fungus Aspergillus sydowii

The biotransformation reactions of alpha-bromoacetophenone (1), p-bromo-alpha-bromoacetophenone (2), and p-nitro-alpha-bromoacetophenone (3) by whole cells of the marine fungus Aspergillus sydowii Ce19 have been investigated. Fungal cells that had been grown in artificial sea water medium containing a high concentration of chloride ions (1.20 M) catalysed the biotransformation of 1 to 2-bromo-1-phenylethanol 4 (56%), together with the alpha-chlorohydrin 7 (9%), 1-phenylethan-1,2-diol 9 (26%), acetophenone 10 (4%) and phenylethanol 11 (5%) identified by GC-MS analysis. In addition, it was observed that the enzymatic reaction was accompanied by the spontaneous debromination of 1 to yield alpha-chloroacetophenone 5 (9%) and alpha-hydroxyacetophenone 6 (18%) identified by GC-FID analysis. When 2 and 3 were employed as substrates, various biotransformation products were detected but the formation of halohydrins was not observed. It is concluded that marine fungus A. sydowii Ce19 presents potential for the biotransformations of bromoacetophenone derivatives.

Development of a new stir bar sorptive extraction coating and its application for the determination of six pesticides in sugarcane juice

In this article, a novel polydimethylsiloxane/activated carbon (PDMS-ACB) material is proposed as a new polymeric phase for stir bar sorptive extraction (SBSE). The PDMS-ACB stir bar, assembled using a simple Teflon (R)/glass capillary mold, demonstrated remarkable stability and resistance to organic solvents for more than 150 extractions. The SBSE bar has a diameter of 2.36 mm and a length of 2.2 cm and is prepared to contain 92 mu L of polymer coating. This new PDMS-ACB bar was evaluated for its ability to determine the quantity of pesticides in sugarcane juice samples by performing liquid desorption (LD) in 200 mu L of ethyl acetate and analyzing the solvent through gas chromatography coupled with mass spectrometry (GC-MS). A fractional factorial design was used to evaluate the main parameters involved in the extraction procedure. Then, a central composite design with a star configuration was used to optimize the significant extraction parameters. The method used demonstrated a limit of quantification (LOQ) of 0.5-40 mu g/L, depending on the analyte detected; the amount of recovery varied from 0.18 to 49.50%, and the intraday precision ranged from 0.072 to 8.40%. The method was used in the analysis of real sugarcane juice samples commercially available in local markets.

Determination of fluoxetine in plasma by gas chromatography-mass spectrometry using stir bar sorptive extraction

This article presents a method employing stir bar sorptive extraction (SBSE) with in situ derivatization, in combination with either thermal or liquid desorption on-line coupled to gas chromatography-mass spectrometry for the analysis of fluoxetine in plasma samples. Ethyl chloroformate was employed as derivatizing agent producing symmetrical peaks. Parameters such as solvent polarity, time for analyte desorption, and extraction time, were evaluated. During the validation process, the developed method presented specificity, linearity (R-2 > 0.99), precision (R.S.D. < 15%), and limits of quantification (LOQ) of 30 and 1.37 pg mL(-1), when liquid and thermal desorption were employed, respectively. This simple and highly sensitive method showed to be adequate for the measurement-of fluoxetine in typical and trace concentration levels. (c) 2008 Elsevier B.V. All rights reserved.