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PubMed1999

Comparison of continuous subcritical water extraction and hydrodistillation of marjoram essential oil.

Continuous subcritical water extraction (CSWE) and hydrodistillation were compared for the extraction of essential oil from marjoram leaves. Ground marjoram leaves (0.4 g) were subjected to dynamic extraction with water at 50 bar, 150 degrees C and 2 ml/min for 15 min. Hydrodistillation was performed treating 140 g of marjoram leaves with 1000 ml of water for 3 h. When CSWE was used the compounds were removed from the aqueous extract by a single extraction with 5 ml of hexane, detected by gas chromatography-flame ionization detection (GC-FID) and identified by mass spectrometry, electronic impact. The CSWE method is quicker (15 min versus 3 h), provides a more valuable essential oil (with higher amounts of oxygenated compounds and no significant presence of terpenes) and allows substantial savings of costs, in terms both of energy and plant material. The efficiency (in terms of volume of essential oil/1 g of plant) of CSWE is 5.1 times higher than that provided by hydrodistillation. The precision of the overall method (CSWE combined with GC-FID) is good (RSD less than 7.5%) for n = 5.

Chromatography, Gas↗

PubMed1986

[Effect of sodium selenite on the activity of antioxidant enzymes (superoxide dismutase, glutathione peroxidase) during hepatocarcinogenesis].

Influence of sodium selenite on functioning of the systems of intracellular generation and detoxication of active oxygen compounds in hepatocarcinogenesis induced by diethylnitrosamine has been studied in experiments on rats. It has been shown that the duration of latent period initiated by ions of Fe2+ chemiluminescence of homogenate of the liver rather objectively reflects the state of the functioning of the systems in charge of the formation and utilization of free radicals of oxygen in a cell. It is supposed that one of the mechanisms of anticarcinogenic action of selenium is connected with its antioxidant functions in the organism and consists in the increase of the activity of superoxide dismutation and selenium-dependent glutathione peroxidases, providing a reliable level of enzymatic protection of normal cells from disturbing action of "active oxygen".

Animals↗

PubMed2002

Novel sulfoxides facilitate GC-rich template amplification.

Certain organic solvents, such as DMSO and betaine, have been reported to enhance PCR amplification, particularly for hard-to-amplify high-GC templates. As a result of extensive structure-activity studies between two groups of compounds--amides and sulfones--we have recently discovered several other potent PCR enhancers. Here we describe the effects of a series of different sulfoxides on GC-rich template amplification and report several of these to be exceptionally effective, often outperforming DMSO. We introduce them as novel PCR enhancers. We identify tetramethylene sulfoxide as the most potent sulfur-oxygen compound in the enhancement of PCR amplification and as one of the most potent PCR enhancers currently known.

Dimethyl Sulfoxide↗

PubMed2004

Solvent-free microwave extraction : an innovative tool for rapid extraction of essential oil from aromatic herbs and spices.

A relatively simple apparatus is described for extracting essential oils from aromatic plant material by atmospheric solvent-free microwave extraction (SFME) without the addition of any solvent or water. Isolation and concentration of volatile compounds were performed by a single stage. The product solutions of volatile compounds were directly analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The essential oils fiom aromatic herbs (basil, crispate mint, thyme) and spices (ajowan, cumin, star anise) extracted by SFME for 30 minutes and I hour, were similar to those obtained by conventional hydro-distillation (HD)for (respectively) 4 and 8 hours. Substantially higher amounts of oxygenated compounds and lower amounts of monoterpenes hydrocarbons are present in the essential oils of the aromatic plants extracted by SFME in comparison with HD. Solvent-free microwave extraction is clearly advantageous to conventional distillation in terms of rapidity, efficiency, cleanliness, substantial saving of energy, and is environmentally friendly.

Chemical Fractionation↗

PubMedDate not supplied

Leaf, branch, stand and landscape scale measurements of volatile organic compound fluxes from U.S. woodlands.

Natural volatile organic compound (VOC) fluxes were measured in three U.S. woodlands in summer 1993. Fluxes from individual leaves and branches were estimated with enclosure techniques and used to initialize and evaluate VOC emission model estimates. Ambient measurements were used to estimate above canopy fluxes for entire stands and landscapes. The branch enclosure experiments revealed 78 VOCs. Hexenol derivatives were the most commonly observed oxygenated compounds. The branch measurements also revealed high rates of isoprene emission from three genera of plants (Albizia, Chusqua and Mahonia) and high rates of monoterpene emission from three genera (Atriplex, Chrysthamnus and Sorbus) for which VOC emission rates have not been reported. Measurements on an additional 34 species confirmed previous results. Leaf enclosure measurements of isoprene emission rates from Quercus were substantially higher than the rates used in existing emission models. Model predictions of diurnal variations in isoprene fluxes were generally within +/- 35% of observed flux variations. Measurements with a fast response analyzer demonstrated that 60 min is a reasonable time resolution for biogenic emission models. Average daytime stand scale (hundreds of m) flux measurements ranged from about 1.3 mg C m(-2) h(-1) for a shrub oak stand to 1.5-2.5 mg C m(-2) h(-1) for a mixed forest stand. Morning, evening and nighttime fluxes were less than 0.1 mg C m(-2) h(-1). Average daytime landscape scale (tens of km) flux measurements ranged from about 3 mg C m(-2) h(-1) for a shrub oak-aspen and rangeland landscape to about 7 mg C m(-2) h(-1) for a deciduous forest landscape. Fluxes predicted by recent versions (BEIS2, BEIS2.1) of a biogenic emission model were within 10 to 50% of observed fluxes and about 300% higher than those predicted by a previous version of the model (BEIS).

Journal Article↗

PubMed1991

Humate-induced activation of human granulocytes.

Naturally occurring humic substances are particular chemical compounds which are found in humus. They bind to carbohydrates, amino acids and steroids by means of hydrogen bonds, covalent bonds and epsilon donor-acceptor complexes. Three specimens of low-molecular humic substances were tested (two naturally occurring humates and one synthetically prepared humate). They were all capable of stimulating certain functions of human neutrophils (PMN), such as the respiratory burst which results in the production of toxic oxygen compounds. This PMN stimulation can be demonstrated with the help of chemiluminescence, as well as by cytochemistry and with the electron microscope. The main product of the humate-induced PMN response is H2O2. There was no activation of neutrophilic chemokinesis or chemotaxis. It is suggested that the low-molecular humic substances originating from decaying organic material contain chemical structures which can act as signals to change dormant PMN into activated cells.

Acridines↗

PubMed2005

Leaf volatile compounds of six citrus somatic allotetraploid hybrids originating from various combinations of lime, lemon, citron, sweet orange, and grapefruit.

Volatile compounds were extracted by a pentane/ether (1:1) mixture from the leaves of six citrus somatic allotetraploid hybrids resulting from various combinations of lime, lemon, citron, sweet orange, and grapefruit. Extracts were examined by gas chromatography-mass spectrometry (GC-MS) and compared with those of their respective parents. All hybrids having an acid citrus parent exhibit the same relative contents in hydrocarbons and oxygenated compounds as the acid citrus, while the (grapefruit + orange) hybrid behaves similarly to its two parents. When volatile compound contents (microg g(-1)) are examined in detail, several behaviors are encountered in hybrids and seem to depend on the presence/absence of the considered parental compound and on the corresponding hybrid combination. Meanwhile, the sesquiterpene hydrocarbons are present in all hybrids at concentrations systematically lower than those of the highest parental producers. Statistical analyses show that hybrids exhibit hardly discriminable aromatic profiles, meaning that no strong dominance of one or the other parent was observed in hybrids with regards to the leaf volatile compound production.

Citrus↗

PubMed2001

Synthesis of bicyclic pyrane derivatives via tungsten-mediated [3 + 3] cycloaddition of epoxides with tethered alkynes.

Propargyltungsten compounds bearing a tethered epoxide were prepared in short steps from readily available materials. In the presence of various Lewis acids, BF(3).Et(2)O catalysts (25 mol %) most effectively promote the [3 + 3] cycloaddition of the epoxide with its tethered propargyltungsten group, delivering bicyclic pyranyltungsten compounds in reasonable yields. This cyclization proceeds highly diastereoselectively with tolerance of various functional groups. The stereochemical outcome indicates that the cycloaddition is initiated by the ring opening of the epoxides via an exo-attack of the propargyltungsten group. The resulting pyranyltungsten organometallics were demetalated to yield various bicyclic pyranyl derivatives using different oxidants. This new method provides a short enantiospecific synthesis of bicyclic oxygen compounds if chiral epoxide is used in the cyclization. A mechanistic model is presented to rationalize the reaction pathway of this [3 + 3] cycloaddition.

Journal Article↗

PubMed2002

Water soluble fractions of rose-scented geranium (Pelargonium species) essential oil.

The essential oil of rose-scented geranium (Pelargonium species, family: Geraniaceae) obtained through steam or water plus steam distillation of shoot biomass is extensively used in the fragrance industry and in aromatherapy. During distillation, a part of the essential oil becomes dissolved in the distillation water (hydrosol) and is lost as this hydrosol is discarded. In this investigation, hydrosol was shaken for 30 min with hexane (10:1 proportion) and the hexane was distilled to yield 'secondary' or 'recovered' essential oil. The chemical composition of secondary oil was compared with that of 'primary' oil (obtained directly by distilling shoot biomass of the crop). Primary oil accounted for 93.0% and secondary oil 7.0% of the total oil yield (100.2 ml from 100 kg green shoot biomass). Fifty-two compounds making up 95.0-98.5% of the primary and the secondary oils were characterized through gas chromatography (GC) and gas chromatography-mass spectroscopy (GC--MS). Primary oil was richer in hydrocarbons (8.5-9.4%), citronellyl formate (6.2-7.5%), geranyl formate (4.1-4.7%), citronellyl propionate (1.0-1.2%), alpha-selinene (1.8-2.2%), citronellyl butyrate (1.4-1.7%), 10-epi-gamma-eudesmol (4.9-5.5%) and geranyl tiglate (1.8-2.1%). Recovered oil was richer in organoleptically important oxygenated compounds (88.9-93.9%), commercial rhodinol fraction (74.3-81.2%), sabinene (0.4-6.2%), cis-linool oxide (furanoid) (0.7-1.2%), linalool (14.7-19.6%), alpha-terpineol (3.3-4.8%) and geraniol (21.3-38.4%). Blending of recovered oil with primary oil is recommended to enhance the olfactory value of the primary oil of rose-scented geranium. Distillation water stripped of essential oil through hexane extraction can be recycled for distilling the next batch of rose-scented geranium.

Biotechnology↗

PubMed1989

Comparative inhibition of rabbit globin mRNA translation by modified antisense oligodeoxynucleotides.

We have studied the translation of rabbit globin mRNA in cell free systems (reticulocyte lysate and wheat germ extract) and in microinjected Xenopus oocytes in the presence of anti-sense oligodeoxynucleotides. Results obtained with the unmodified all-oxygen compounds were compared with those obtained when phosphorothioate or alpha-DNA was used. In the wheat germ system a 17-mer sequence targeted to the coding region of beta-globin mRNA was specifically inhibitory when either the unmodified phosphodiester oligonucleotide or its phosphorothioate analogue were used. In contrast no effect was observed with the alpha-oligomer. These results were ascribed to the fact that phosphorothioate oligomers elicit an RNase-H activity comparable to the all-oxygen congeners, while alpha-DNA/mRNA hybrids were a poor substrate. Microinjected Xenopus oocytes followed a similar pattern. The phosphorothioate oligomer was more efficient to prevent translation than the unmodified 17-mer. Inhibition of beta-globin synthesis was observed in the nanomolar concentration range. This result can be ascribed to the nuclease resistance of phosphorothioates as compared to natural phosphodiester linkages, alpha-oligomers were devoid of any inhibitory effect up to 30 microM. Phosphorothioate oligodeoxyribonucleotides were shown to be non-specific inhibitors of protein translation, at concentrations in the micromolar range, in both cell-free systems and oocytes. Non-specific inhibition of translation was dependent on the length of the phosphorothioate oligomer. These non-specific effects were not observed with the unmodified or the alpha-oligonucleotides.

Animals↗

PubMed2006

Regio and stereoselective oxidations of unsaturated steroidal compounds with H2O2 mediated by CH3ReO3.

We have investigated the oxidative behavior of sterols such as cholesteryl acetate (1), 7-dehydrocholesteryl acetate (2), ergosteryl acetate (3), cholecalciferol acetate (Vitamin D(3) acetate) (4) and ergocalciferol acetate (Vitamin D(2) acetate) (5) with the oxidant system methyltrioxorhenium/H(2)O(2)/pyridine in order to check potential parameters controlling the selectivity. The reactions, performed in CH(2)Cl(2)/H(2)O at 25 degrees C, have shown good regio- and stereoselectivity. All oxidation products were isolated by high-performance liquid chromatography (HPLC) and characterized by MS(EI) or FAB, (1)H NMR, (13)C NMR, APT, COSY, HSQC, HMBC, ROESY and NOEDS measurements. Seven new oxygenated compounds were also obtained. Under the experimental conditions adopted in this work, only the diene steroids, i.e. 7-dehydrocholesteryl acetate and ergosteryl acetate, undergo hydrolytic oxirane ring opening, whereas Vitamin D(2) and D(3) acetates, containing the triene system and cholesteryl acetate yield only epoxides. The selectivity seems to be controlled by the nucleophilicity of double bonds and by stereoelectronic and steric effects.

Cholecalciferol↗

PubMed2004

Solvent-free microwave extraction of essential oil from aromatic herbs: comparison with conventional hydro-distillation.

Solvent-free microwave extraction (SFME) is a combination of microwave heating and dry distillation, performed at atmospheric pressure without added any solvent or water. Isolation and concentration of volatile compounds are performed by a single stage. SFME has been compared with a conventional technique, hydro-distillation (HD), for the extraction of essential oil from three aromatic herbs: basil (Ocimum basilicum L.), garden mint (Mentha crispa L.), and thyme (Thymus vulgaris L.). The essential oils extracted by SFME for 30min were quantitatively (yield) and qualitatively (aromatic profile) similar to those obtained by conventional hydro-distillation for 4.5 h. The SFME method yields an essential oil with higher amounts of more valuable oxygenated compounds, and allows substantial savings of costs, in terms of time, energy and plant material. SFME is a green technology and appears as a good alternative for the extraction of essential oils from aromatic plants.

Costs and Cost Analysis↗

PubMed2005

Phagocytic and oxidative burst activity of neutrophils in the end stage of liver cirrhosis.

AIM: To evaluate the phagocytic activity and neutrophil oxidative burst in liver cirrhosis. METHODS: In 45 patients with advanced postalcoholic liver cirrhosis (aged 45+/-14 years) and in 25 healthy volunteers (aged 38+/-5 years), the percentage of phagocytizing cells after in vitro incubation with E. coli (Phagotest Kit), phagocytic activity (mean intensity of fluorescence, MIF) and the percentage of neutrophil oxidative burst (Bursttest Kit), and the level of free oxygen radical production (MIF of Rodamine 123) were analyzed by flow cytometry. The levels of soluble sICAM-1, sVCAM-1, sP-selectin, sE-selectin, sL-selectin, and TNF-alpha were determined in blood serum. RESULTS: The percentage of E. coli phagocytizing neutrophils in liver cirrhosis patients was comparable to that in healthy subjects. MIF of neutrophil -- ingested E. coli was higher in patients with liver cirrhosis. The oxidative burst in E. coli phagocytizing neutrophils generated less amount of active oxygen compounds in liver cirrhosis patients (MIF of R123: 24.7+/-7.1 and 29.7+/-6.6 in healthy, P<0.01). Phorbol myristate acetate (PMA) -- stimulated neutrophilsproduced less reactive oxidants in liver cirrhosis patients than in healthy subjects (MIF of R123: 42.7+/-14.6 vs 50.2+/-13.3, P<0.01). A negative correlation was observed between oxidative burst MIF of PMA-stimulated neutrophils and ALT and AST levels (r -0.35, P<0.05; r-0.4, P<0.03). sVCAM-1, sICAM-1, sE-selectin concentrations correlated negatively with the oxygen free radical production (MIF of R123) in neutrophils after PMA stimulation in liver cirrhosis patients (r-0.45, P<0.05; r-0.41, P<0.05; r-0.39, P<0.05, respectively). CONCLUSION: Neutrophil metabolic activity diminishes together with the intensification of liver failure. The metabolic potential of phagocytizing neutrophils is significantly lower in liver cirrhosis patients, which can be one of the causes of immune mechanism damage. The evaluation of oxygen metabolism of E. coli-stimulated neutrophils reveals that the amount of released oxygen metabolites is smaller in liver cirrhosis patients than in healthy subjects.

Adult↗

PubMed1993

Activated murine neutrophils induce unscheduled DNA synthesis in B lymphocytes.

Activated neutrophils induce DNA damage in neighboring cells by secreting reactive oxygen compounds into the extracellular milieu. Repair of this damage is required to prevent mutagenesis and neoplastic transformation. Conditions were established to detect the activation of excision-repair pathways (unscheduled DNA synthesis) by measuring stimulated thymidine uptake in target B lymphocytes exposed to activated neutrophils. Murine neutrophils were cocultured in serum-free medium with splenic B cells or with murine plasmacytoma cells for 2 h. Unscheduled DNA synthesis in the B cells was detected at neutrophil:target cell ratios of 1:1 to 4:1 when the neutrophils were activated with phorbol myristate acetate. Reagent H2O2 alone (> or = 6 microM) also induced UDS whereas HOCl (up to 4 mM) did not. No repair synthesis was observed within the neutrophils themselves. Control experiments indicated that the induction of UDS by neutrophils and H2O2 was not due to formation of a stable genotoxic compound from HU. On the contrary, scavenging of free H2O2 by HU probably lowered the levels of UDS that could be detected by these agents. Induction of unscheduled DNA synthesis by neutrophils and H2O2 occurred under conditions of less cytostasis than was found with other DNA-damaging agents such as 4-nitroquinoline 1-oxide or gamma-irradiation. This may reflect a heightened responsiveness of the cells to repair of damage from physiological oxidants. The results demonstrate that DNA damage induced by reactive oxygen intermediates can be repaired by nucleotide excision-repair pathways.

Animals↗

PubMed1983

Functional activity of enucleated human polymorphonuclear leukocytes.

Enucleated human polymorphonuclear leukocytes (PMN) were prepared by centrifuging isolated, intact PMN over a discontinuous Ficoll gradient that contained 20 microM cytochalasin B. The enucleated cells (PMN cytoplasts) contained about one-third of the plasma membrane and about one-half of the cytoplasm present in intact PMN. The PMN cytoplasts contained no nucleus and hardly any granules. The volume of the PMN cytoplasts was about one-fourth of that of the original PMN. Greater than 90% of the PMN cytoplasts had an "outside-out" topography of the plasma membrane. Cytoplasts prepared from resting PMN did not generate superoxide radicals (O2-) or hydrogen peroxide. PMN cytoplasts incubated with opsonized zymosan particles or phorbol-myristate acetate induced a respiratory burst that was qualitatively (O2 consumption, O2- and H2O2 generation) and quantitatively (per unit area of plasma membrane) comparable with that of intact, stimulated PMN. Moreover, at low ratios of bacteria/cells, PMN cytoplasts ingested opsonized Staphylococcus aureus bacteria as well as did intact PMN. At higher ratios, the cytoplasts phagocytosed less well. The killing of these bacteria by PMN cytoplasts was slower than by intact cells. The chemotactic activity of PMN cytoplasts was very low. These results indicate that the PMN apparatus for phagocytosis, generation of bactericidal oxygen compounds, and killing of bacteria, as well as the mechanism for recognizing opsonins and activating PMN functions, are present in the plasma membrane and cytosol of these cells.

Blood Bactericidal Activity↗

PubMed2003

Preliminary characterization of anhydrous ethanol used in Brazil as automotive fuel.

This work reports preliminary studies on the characterisation of anhydrous ethanol (AEA) used as an automotive fuel mixed with gasoline in Porto Alegre (South Brazil). Pre-concentration of the impurities contained in 1000 ml of AEA was carried on through solid-phase extraction using XAD4 resin. The main compounds in the extract were identified by means of spectral data from the library of the equipment. The concentrate was then fractionated using a preparative liquid chromatographic column filled with activated silica gel and the elution procedure was carried out with, n-hexane, n-hexane-benzene (1:1, v/v) and dichloromethane. Prior to analysis by GC-MS, each fraction was reduced to 1 ml with a gentle stream of nitrogen. Saturated linear hydrocarbons and aromatic hydrocarbons eluted in the first fraction and oxygenated compounds such as aldehydes. ketones and alcohols, eluted in the second one. were the main compounds detected in the sample.

Brazil↗

PubMed2001

Evaluation of standard methods for the analysis of methyl tert-butyl ether and related oxygenates in gasoline-contaminated groundwater.

The U.S. Environmental Protection Agency (EPA) now requires monitoring of oxygenate compounds in groundwater at leaking underground storage tank (LUST) sites nationwide. Three purge-and-trap gas chromatography methods most commonly employed for this purpose were tested, and their performance as a function of total petroleum hydrocarbon (TPH) content of the sample matrix was determined. Tests included a formal method evaluation, a round-robin study, and a split-sample study (424 groundwater samples). Consistently good results were achieved with EPA Method 8240B/60B (mass spectrometry) and ASTM Method D4815 (flame ionization detection) when five oxygenates were monitored in reagent water and gasoline. However, one protocol routinely employed for analysis of LUST samples had serious limitations: EPA Method 8020A/21B (photoiozination detection) was unfit for monitoring of tert-butyl alcohol (TBA) and frequently yielded false-positive (12-50% of samples) and inaccurate results when ether oxygenates were monitored in aqueous samples containing high concentrations of TPH (> 1,000 microg/ L). Thus, care should be taken in the analysis of LUST databases populated with EPA Method 8020/21 data because results reported for methyl tert-butyl ether (MTBE) in samples containing high levels of TPH have a high likelihood of being inaccurate or false-positive. For all three methods, detection limits determined in reagent water were sufficiently low for monitoring MTBE at the stringent primary (13 microg/L) and secondary (5 microg/L) action levels set by the state of California.

Carcinogens↗

PubMed2006

Anti-inflammatory neolignans from Piper kadsura.

Two new neolignans, piperkadsin A (1) and piperkadsin B (2), as well as 11 known neolignans, three known alkaloids, the highly oxygenated compound (+)-crotepoxide, and stigmasterol were isolated from the stems of Piper kadsura. The anti-inflammatory activities of these compounds were evaluated. Compounds 1, 2, futoquinol (3), piperlactam S (4), and N-p-coumaroyl tyramine (5) showed potent inhibition of PMA-induced ROS production in human polymorphonuclear neutrophils with IC(50) values 4.3 +/-1.0, 12.2 +/- 3.2, 13.1 +/- 5.3, 7.0 +/- 1.9, and 8.4 +/- 1.3 microM, respectively.

Anti-Inflammatory Agents, Non-Steroidal↗