883 resultados para volatile oil


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Primula obconica was introduced to Europe from Hubei, China in 1880, and has been cultivated worldwide as one of popular ornamental plants. The volatile oil of wild P. obconica collected from its original place, Yichang, Hubei was first investigated. A total of 43 compounds constituting 93.49% of the oil were identified by using GC and GC-MS. The major compounds were methyl 2,4-dihydroxy-5-methyl benzoate (30.41%), methyl 2,6-dihydroxy-4-methyl benzoate (29.27%), and hypnone (8.92%) etc. In comparison with the published data of some European cultivars, the native P. obconica seems to be allergen-free due to absence of primin and miconidin.

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An overview of the studies carried out in our laboratories on supercritical fluid extraction (SFE) of volatile oils from seven aromatic plants: pennyroyal (Mentha pulegium L.), fennel seeds (Foeniculum vulgare Mill.), coriander (Coriandrum sativum L.), savory (Satureja fruticosa Beguinot), winter savory (Satureja montana L.), cotton lavender (Santolina chamaecyparisus) and thyme (Thymus vulgaris), is presented. A flow apparatus with a 1 L extractor and two 0.27 L separators was built to perform studies at temperatures ranging from 298 to 353 K and pressures up to 30.0 MPa. The best compromise between yield and composition compared with hydrodistillation (HD) was achieved selecting the optimum experimental conditions of extraction and fractionation. The major differences between HD and SFE oils is the presence of a small percentage of cuticular waxes and the relative amount of thymoquinone, an oxygenated monoterpene with important biological properties, which is present in the oils from thyme and winter savory. On the other hand, the modeling of our data on supercritical extraction of volatile oil from pennyroyal is discussed using Sovova's models. These models have been applied successfully to the other volatile oil extractions. Furthermore, other experimental studies involving supercritical CO2 carried out in our laboratories are also mentioned.

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The essential oil from leaves of Guarea guidonia was subjected to chromatographic separation procedures to afford nine sesquiterpenes; two of them are new eudesmane derivatives. The chemical structures of the obtained compounds were characterised by spectrometric analysis, mainly mass spectrometry and NMR.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The Amazon Indians Waiapi living in the West of Amapa State of Brazil, treat malaria with an inhalation of vapor obtained from leaves of Viola surinamensis. The essential oil obtained from adult and plantlet leaves was analyzed by GC/MS and 11 monoterpenes, 11 sesquiterpenes and three phenylpropanoids were identified. Plantlet essential oil caused 100% of growth inhibition after 48 h in the development of the young trophozoite to schizont stage and the sesquiterpene nerolidol (100 mu g/ml) was identified as one of the active constituents (100% of growth inhibition was obtained). In addition, examination of [(UC)-C-14]-glucose incorporation showed that activity of nerolidol is related to the inhibition of glycoprotein biosynthesis. (C) 1999 Elsevier B.V. Ireland Ltd. All rights reserved.

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The essential oil obtained by hydrodistillation of fresh leaves of Psidium cattleianum Sabine, collected in the Atlantic Forest in southeastern Brazil, was analyzed by GC and GC/MS. The oil had the main constituents alpha-thujene (25.2%), 1,8-cineole (16.4%) and beta-caryophyllene (10.2%).

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The modelling of the experimental data of the extraction of the volatile oil from six aromatic plants (coriander, fennel, savoury, winter savoury, cotton lavender and thyme) was performed using five mathematical models, based on differential mass balances. In all cases the extraction was internal diffusion controlled and the internal mass transfer coefficienty (k(s)) have been found to change with pressure, temperature and particle size. For fennel, savoury and cotton lavender, the external mass transfer and the equilibrium phase also influenced the second extraction period, since k(s) changed with the tested flow rates. In general, the axial dispersion coefficient could be neglected for the conditions studied, since Peclet numbers were high. On the other hand, the solute-matrix interaction had to be considered in order to ensure a satisfactory description of the experimental data.

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A discussion of the most interesting results obtained in our laboratories, during the supercritical CO(2) extraction of bioactive compounds from microalgae and volatile oils from aromatic plants, was carried out. Concerning the microalgae, the studies on Botryococcus braunii and Chlorella vulgaris were selected. Hydrocarbons from the first microalgae, which are mainly linear alkadienes (C(23)-C(31)) with an odd number of carbon atoms, were selectively extracted at 313 K increasing the pressure up to 30.0 MPa. These hydrocarbons are easily extracted at this pressure, since they are located outside the cellular walls. The extraction of carotenoids, mainly canthaxanthin and astaxanthin, from C. vulgaris is more difficult. The extraction yield of these components at 313 K and 35.0 MPa increased with the degree of crushing of the microalga, since they are not extracellular. On the other hand, for the extraction of volatile oils from aromatic plants, studies on Mentha pulegium and Satureja montana L were chosen. For the first aromatic plant, the composition of the volatile and essential oils was similar, the main components being the pulegone and menthone. However, this volatile oil contained small amounts of waxes, which content decreased with decreasing particle size of the plant matrix. For S. montana L it was also observed that both oils have a similar composition, the main components being carvacrol and thymol. The main difference is the relative amount of thymoquinone, which content can be 15 times higher in volatile oil. This oxygenated monoterpene has important biological activities. Moreover, experimental studies on anticholinesterase activity of supercritical extracts of S. montana were also carried out. The supercritical nonvolatile fraction, which presented the highest content of the protocatechuic, vanilic, chlorogenic and (+)-catechin acids, is the most promising inhibitor of the enzyme butyrylcholinesterase. In contrast, the Soxhlet acetone extract did not affect the activity of this enzyme at the concentrations tested. (C) 2011 Elsevier B.V. All rights reserved.

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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.

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The volatile oil composition and anti-acetyl cholinesterase activity were analyzed in two specimens of Marlierea racemosa growing in different areas of the Atlantic Rain Forest (Cananeia and Caraguatatuba, SP, Brazil). Component identifications were performed by GUMS and their acetyl cholinesterase inhibitory activity was measured through colorimetric analysis. The major constituent in both specimens was spathulenol (25.1 % in Cananeia and 31.9% in Caraguatatuba). However, the first one also presented monoterpenes (41.2%), while in the Carguatatuba plants, this class was not detected. The oils from the plants collected in Cananeia were able to inhibit the acetyl cholinesterase activity by LIP to 75%, but for oils from the other locality the maximal inhibition achieved was 35%. These results suggested that the monoterpenes are more effective in the inhibition of acetyl cholinesterase activity than sesquiterpenes as these compounds are present in higher amounts in the M. racemosa plants collected in Cananeia.

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A kőolaj (és a földgáz), a XX. században felfutott fosszilis energiahordozók történetileg a szenet váltották fel. Ma egyértelműen meghatározzák a világ energiafelhasználását. Miután fosszilisak, rövid távon nem újratermelhetőek, ezért felhasználásuk történetét végigkísérte a feltárt és feltárható készletek mennyiségének állandó újrabecslése is, és folyamatosan jelen van a végességükre vonatkozó apokaliptikus kép, amit az elmúlt 40 év rendkívül hektikus, sokszor kiugróan magas árai is alátámasztanak. Cikkünkben reális képet szeretnénk adni az olaj mennyiségi és árváltozásairól, és ezek lehetséges közgazdasági, társadalmi hatásairól. Miután a rendelkezésre álló hely kevés, csak a legfontosabb összefüggéseket emeljük ki, bizonyos adatokat is inkább illusztrációszerűen közlünk. Célunk nem mélyelemzés, hanem egy átfogó helyzetkép. Vázoljuk a kőolajjal kapcsolatos fontosabb történeti mozzanatokat, a kőolaj felhasználásának irányait Európában és Magyarországon, valamint a készletekkel kapcsolatos összefoglaló gondolatokat. _______________ The volatile oil prices of the past 40 years have always foreshadowed an apocalyptic vision of the exhaustion of global reserves. The paper reviews the important historical moments of the usage of oil, with a special focus on Europe and Hungary. It also details issues related to oil reserves. The main conclusions of the paper are the following: (1) fears of exhausting oil reserves have been rebutted several times; (2) high oil prices can be barriers to the development of the transportation sector, even if innovation is happening in the background; (3) the distribution of oil reserves carries huge political risks; and (4) it is unclear what will take the place of oil as the main source of energy.

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Increases in oil prices after the economic recession have been surprising for domestic oil production in the United States since the beginning of 2009. Not only did the conventional oil extraction increase, but unconventional oil production and exploration also improved greatly with the favorable economic conditions. This favorable economy encourages companies to invest in new reservoirs and technological developments. Recently, enhanced drilling techniques including hydraulic fracturing and horizontal drilling have been supporting the domestic economy by way of unconventional shale and tight oil from various U.S. locations. One of the main contributors to this oil boom is the unconventional oil production from the North Dakota Bakken field. Horizontal drilling has increased oil production in the Bakken field, but the economic issues of unconventional oil extraction are still debatable due to volatile oil prices, high decline rates of production, a limited production period, high production costs, and lack of transportation. The economic profitability and viability of the unconventional oil play in the North Dakota Bakken was tested with an economic analysis of average Bakken unconventional well features. Scenario analysis demonstrated that a typical North Dakota Bakken unconventional oil well is profitable and viable as shown by three financial metrics; net present value, internal rate of return, and break-even prices.