Search results for "Chemical composition"
showing 10 items of 377 documents
Composition and Antibacterial Activity of Essential Oils ofCladanthus arabicusCass. (Asteraceae)
2005
Abstract The chemical composition of the essential oils of the aerial parts (stems and leaves: sample A) and flowers (sample B) of Cladanthus arabicus Cass., were analysed by GC-MS. Monoterpenes hydrocarbons constituted the main chemical group in both essential oils, with Sabinene, β-pinene, α-pinene, myrcene, α-phellandrene and p-cymene as the main compounds. Sample A was tested for its antimicrobial activity against six Gram positive and negative bacteria. Results showed that the oil exhibited a significant antibacterial activity.
Phytotoxic effects of essential oils of Nepeta curviflora Boiss and Nepeta nuda L.subsp. albiflora growing wild in Lebanon
2009
The chemical composition of the essential oils of two Nepeta species collected in Lebanon was studied by means of GC and GC-MS analysis. The essential oil from N. curviflora Boiss. contained high amounts of β-caryophyllene (41.6%), caryophyllene oxide (9.5%), (E)-β-farnesene (6.2%) and (Z)-β-farnesene (4.8%); in the oil from N. nuda L. subsp. albiflora (Boiss.) Gams. collected in Laklouk the main compounds were β-bisabolene (11.8%), pulegone (10.8%), (E,Z)-nepetalactone (8.0%), (E)-β-farnesene (7.1%) and caryophyllene oxide (6.9%), while N. nuda L. subsp. albiflora collected in Tannourine Cedar Forest contained high percentages of hexadecanoic acid (10.1%), β-bisabolene (7.8%), caryophyllen…
Near infrared reflectance spectroscopy (NIRS) characterization of European sea bass (Dicentrarchus labrax) from different rearing systems
2009
The present study aimed to predict by NIRS the proximate chemical composition and some carcass traits of sea bass coming from 11 farms with different rearing systems (extensive, intensive in land-based basins, sea cages) and located in northern (Friuli, Veneto), central (Tuscany) and southern (Puglia and Sicily) Italy. NIRS analysis of freeze dried sea bass fillets gave fairly good predictions of slaughter weight and fillet yield (R2cv=0.48-0.55), while results for carcass yield were poor. NIRS analysis was highly predictive for the condition factor (R2cv=0.790, SECV=0.09) and for water, ether extract and gross energy showing high correlations (R2cv>0.90) with NIR spectral infor- mation and…
Essential oil composition ofArtemisia parvi?ora aerial parts
2003
The chemical composition of the essential oil from aerial parts of A. parviflora was analysed by GC and GC–MS. Twenty-two compounds, accounting for 72.7% of the oil, were identified. The main components identified were β-caryophyllene (15.3%), germacrene D (14.7%), camphor (11.4%), artemisia ketone (7.8%), 1,8-cineole (5.8%), α-copaene (2.6%), artemisia alcohol (2.6%), terpinene-4-ol (2.3%), caryophyllene oxide (1.2%), α-pinene (1.1%), sabinyl acetate (1.1%) and α-humulene (1.1%). Copyright © 2003 John Wiley & Sons, Ltd.
Chemical Composition of the Leaf Oil ofLantana camara
2005
The essential oil of the fresh leaves of Lantana camera growing in Dehra Dun was analyzed by GC and GC/MS. The major constituents identified in the oil included β-caryophyllene (23.3%), α-humulene (11.5%), germacrene D (10.9%), davanone (7.3%) and γ-curcumene (6.3%).
In situ submicron organic aerosol characterization at a boreal forest research station during HUMPPA-COPEC 2010 using soft and hard ionization mass s…
2013
The chemical composition of submicron aerosol during the comprehensive field campaign HUMPPA-COPEC 2010 at Hyytiälä, Finland, is presented. The focus lies on online measurements of organic acids, which were achieved by using atmospheric pressure chemical ionization (APCI) ion trap mass spectrometry (IT-MS). These measurements were accompanied by aerosol mass spectrometry (AMS) measurements and Fourier transform infrared spectroscopy (FTIR) of filter samples, all showing a high degree of correlation. The soft ionization mass spectrometer alternated between gas-phase measurements solely and measuring the sum of gas and particle phase. The AMS measurements of C, H and O elemental composition s…
UHPLC-Orbitrap mass spectrometric characterization of organic aerosol from a central European city (Mainz, Germany) and a Chinese megacity (Beijing)
2018
Abstract Fine urban aerosol particles with aerodynamic equivalent dimeter ≤2.5 μm (PM2.5) were collected in Mainz (a city within the Rhine-Main area, the third largest metropolitan region in Germany) and Beijing (Chinese megacity). A solvent mixture of acetonitrile-water was used to extract the organic aerosol fraction (OA) from the particle samples. The extracts were analyzed by an ultrahigh resolution mass spectrometer (UHRMS) Orbitrap coupled with ultra-high-performance liquid chromatography (UHPLC) both in the negative and positive ion mode. The number of compounds observed in Beijing is a factor of 2–10 higher compared to Mainz. The clear differences on chemical composition of OA in th…
Tocopherol, fatty acid and phytosterol content in seeds of nine wild taxa of Sicilian Brassica (Cruciferae)
2010
The purpose of this study was to determine tocopherol (Toc), fatty acid and phytosterol content in dry seeds of nine wild taxa of Sicilian Brassica sect. Brassica. Analyses were performed by gas chromatography (GC)-mass spectroscopy (MS). The biochemical analysis of dry seeds showed that in the nine taxa examined, α - and γ -Toc were the major isomers, δ - Toc was present in traces and β -Toc was never found. All taxa had a similar fatty acid composition with C 16:0 (357.2 mg kg − 1 DW), C 18:1 (393.94 mg kg − 1 DW) and C 22:1 (618.29 mg kg − 1 DW) acids present in higher amount. Unsaturated fatty acids (52.5–66.5%) were more abundant than saturated (33.5–47.5%) ones relative to the total f…
Distribution of Δ5-olefinic acids in the triacylglycerols fromPinus koraiensisandPinus pinasterseed oils
1996
Purified triacylglycerols (TAG) fromPinus koraiensis andP. pinaster seed oils, which are interesting and commercially available sources of Δ5-olefinic acids (i.e.,cis-5,cis-9,cis-12 18:3 andcis-5,cis-11,cis-14 20:3 acids) were fractionated by reversed-phase high-performance liquid chromatography, and each fraction was examined by capillary gas-liquid chromatography for its fatty acid composition. A structure could be assigned to more than 92% of TAG from both oils. In both instances, ca. 48% of the TAG were shown to contain at least one δ5-olefinic acid. In the great majority of TAG, our data showed that there is only one molecule of δ5-olefinic acid per molecule of TAG. This is compatible …
Effect of pHand age of culture on cellular fatty acid composition of Leuconostoc oenos
1996
Z. DRICI-CACHON, J.F. CAVIN AND C. DIVIES. 1996. This study is concerned with the fatty acid composition of three strains of Leuconostoc oenos grown at different pH. The most abundant fatty acids were C18: 1w9, C19: 0 cy(w9,10) and C16:0, followed by C16: 1w9 and C14: 0. The pH considerably modified the fatty acid distribution in Lo107 (an acidophilic strain) and Lo8413 (a moderately acidophilic strain). However, moderate changes occurred for LoATCC 23277 (a less acidophilic strain). At pH 2.9, Lo107 has a remarkably high level of C19: 0 cy-(w9,10) and C19:0 cy(w11,12). Proportions of C18: 1 and C19:0 cyclo acids varied mainly with the pH of the medium and also as a function of growth phase…