Search results for "monoterpene"
showing 10 items of 145 documents
The influence of the temperature on the liquid–liquid equlibria of the mixture limonene + ethanol + H2O
2004
Abstract In this work, experimental liquid–liquid equilibria (LLE) of the limonene + ethanol + water system are presented. The LLE of this system has been measured at 293.15, 303.15, 313.15 and 323.15 K. The equilibrium data presented are correlated using NRTL and UNIQUAC equations. Finally, the reliability of these models is tested by comparison with experimental results.
Liquid–liquid equlibria of the mixture linalool+ethanol+water at different temperatures
2005
Abstract In this work, experimental liquid–liquid equilibria (LLE) data of the linalool + ethanol + water system are presented. The LLE of this system has been measured at 293.15, 303.15, 313.15 and 323.15 K. The equilibrium data presented are correlated using NRTL and UNIQUAC equations. Finally, the reliability of these models is tested by comparison with experimental results.
Composition and antimicrobial activity of the essential oil of Achillea falcata L. (Asteraceae).
2005
The composition of the essential oil from aerial parts of Achillea falcata L. (Asteraceae) growing wild in Lebanon was analysed by GC and GC–MS; 58 compounds, representing 94.4% of the oil, were identified. Isomers of the cyclobutane ethanol, 1-methyl-2-(1-methylethenyl), grandisol (21.4%) and fragranol (16.8%) were the main components of the oil. Also abundant were artemisia ketone (5.2%), terpinen-4-ol (4.5%) and 1,8-cineole (4.0%). The essential oil shows inhibitory activity mainly against Gram-positive bacteria.
Chemical composition, antioxidant and anticholinesterase activity of the essential oil of algerian cachrys sicula L
2021
In this work, in order to explore a new Algerian medicinal plant used in traditional medicine, the essential oil of the leaves of Cachrys sicula L. (Apiaceae) collected from Algeria, obtained by hydrodistillation, was analyzed by GC/MS. Thirty-two compounds were identified accounting for 98.6% of the total oil, which is characterized by a high content of monoterpene hydrocarbons (74.8%). The main constituents of the essential oil were β-pinene (17.9%), sabinene (17.8%), myrcene (12%), and α-pinene (11.4%). In vitro antioxidant activity of the essential oil was assayed by three methods, namely ABTS•+, metal chelating, and DPPH• assays. The antioxidant activity of the oil was higher in the AB…
New oxygenated eudesmanolides from artemisia herba-alba
1990
Abstract The aerial parts of Artemisia herba-alba Asso subsp.valentina Lam. (Asteraceae) yielded the new eudesmanolides 1-11 and the new sesquiterpene-monoterpene adducts 12-13. The absolute configuration of compound 6 was confirmed with the aid of X-ray diffraction analysis. Some aspects of the thermal and photochemical reactivity of 2,4-cyclohexadienones are discussed.
Composition of the essential oil ofPallenis spinosa (L.) Cass. (Asteraceae)
2003
The essential oil of Pallenis spinosa (L.) Cass. was obtained by hydrodistillation. In total 38 components were identified by GC and GC–MS. Oxygenated sesquiterpenoids amounted to 60.2% of the oil. The main components were germacra-1(10),5-dien-3,4-diol (18.4%), α-cadinol (14.1%), 3-acetoxygermacra-1(10),5-dien-4-ol (13.0%), T-cadinol (8.2%) and δ-cadinene (5.8%). The oil does not show antimicrobial activity. Copyright © 2003 John Wiley & Sons, Ltd.
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.
Formation of Aroma by Hydrolysis of Glycosidically Bound Components
1992
SUMMARY Acid hydrolysis has been used in order to establish the presence of glycosidically bound components in fruits. During this treatment, rearrangement reactions of free monoterpene alcohols generally occur. This inconvenient may be avoided using enzymatic hydrolysis, however the specificity of enzymes requires the previous knowledge of the structures of compounds used as substrates in order to control the reaction. Several glycosidically bound components, glucosides, rutinosides and arabinoglucosides present in grapes and apricot were isolated, separated and identified using non destructive methods, MS-MS low energy CAD spectra and HPLC. s-D-glucosidase, α-L-rhamnosidase, α-L-arabinase…
Suppression of new particle formation from monoterpene oxidation by NO<sub>x</sub>
2014
Abstract. The impact of nitrogen oxides (NOx = NO + NO2) on new particle formation (NPF) and on photochemical ozone production from real plant volatile organic compound (BVOC) emissions was studied in a laboratory setup. At high NOx conditions ([BVOC] / [NOx] < 7, [NOx] > 23 ppb) new particle formation was suppressed. Instead, photochemical ozone formation was observed resulting in higher hydroxyl radical (OH) and lower nitrogen monoxide (NO) concentrations. When [NO] was reduced back to levels below 1 ppb by OH reactions, NPF was observed. Adding high amounts of NOx caused NPF to be slowed by orders of magnitude compared to analogous experiments at low NOx conditions ([NOx] ~300 ppt)…
Total synthesis of the monoterpenes (−)-mintlactone and (+)-isomintlactone
1992
Abstract The first total stereodirected synthesis of the monoterpenes (−)-mintlactone and (+)-isomintlactone from the same chiral starting product is described. A stereoselective, radical-mediated ring closure was the key step in both syntheses.