Alpha-pinene

The chemical composition of the essential oil of the flowering branches and fresh leaves of Rosmarinus officinalis L. from Saudi Arabia was analysed by gas chromatography-based techniques (GC and GC/MS). 63 compounds were identified and amounted to 94.64 % of the total oils. The presence of oxygenated monoterpenes (51.70%) characterized the oil of Saudi Arabian rosemary. R. officinalis oil was also rich with monoterpene hydrocarbons (28.45%) and acyclic monoterpenes (8.64%). Sesquiterpenes (1.28%) were minor compounds in the oils of this plant. The dominant constituents (56.09 %) were 1,8-Cineole (23.16%), α-Pinene (19.48%) and Verbinone (13.45%).

The hydrodistilled leaf essential oil of Machilus philippinensis was analyzed to determine its composition and yield. Seventy compounds were identified, the main ones being β-caryophyllene (13.6%), α-pinene (12.0%), α-cadinol (7.4%), cis-ocimene (7.0%), spathulenol (5.6%), (E)-nerolidol (5.3%), tau-cadinol (4.8%) and β-pinene (4.5%). Monoterpene hydrocarbons (36.1%) and oxygenated sesquiterpenes (33.0%) were the predominant groups of compounds. The leaf oil exhibited excellent anti-wood-decay fungal activities.

Speciated particle-phase organic nitrates (pONs) were quantified using online chemical ionization MS during June and July of 2013 in rural Alabama as part of the Southern Oxidant and Aerosol Study. A large fraction of pONs is highly functionalized, possessing between six and eight oxygen atoms within each carbon number group, and is not the common first generation alkyl nitrates previously reported. Using calibrations for isoprene hydroxynitrates and the measured molecular compositions, we estimate that pONs account for 3% and 8% of total submicrometer organic aerosol mass, on average, during the day and night, respectively. Each of the isoprene- and monoterpenes-derived groups exhibited a strong diel trend consistent with the emission patterns of likely biogenic hydrocarbon precursors. An observationally constrained diel box model can replicate the observed pON assuming that pONs (i) are produced in the gas phase and rapidly establish gas-particle equilibrium and (ii) have a short ...

Hydrodistillation of the dried leaves of eleven species of the genus Eucalyptus L'Hér., i.e., E. astringens Maiden, E. camaldulensis Dehnh., E. diversifolia Bonpl., E. falcata Turcz., E. ficifolia F. Muell., E. gomphocephala DC., E. lehmannii (Schauer) Benth., E. maculata Hook., E. platypus Hook., E. polyanthemos Schauer, and E. rudis Endl., harvested from Korbous arboreta (region of Nabeul, northeast of Tunisia) in April 2006, afforded essential oils in yields varying from 0.1±0.1 to 3.8±0.1%, dependent on the species. E. astringens and E. ficifolia showed the highest and the lowest mean percentage of essential oil amongst all the species examined, respectively. Analysis by GC (RI) and GC/MS allowed the identification of 138 components, representing 74.0 to 99.1% of the total oil. The contents of the different samples varied according to the species. The main components were 1,8‐cineole, followed by trans‐pinocarveol (1), spathulenol (2), α‐pinene, p‐cymene, (E,E)‐farnesol, cry...

Hydrodistillation of the dried leaves of twelve species of the genus Eucalyptus L' Hér., i.e., E. brockwayi C. A. Gardn., E. gracilis F. Muell., E. gillii Maiden, E. largiflorens F. Muell., E. loxophleba Benth., E. occidentalis Endl., E. oldfieldii F. Muell., E. salmonophloia F. Muell., E. sargentii Maiden, E. stricklandii Maiden, E. torquata Luehm., and E. woodwardii Maiden, harvested from Hajeb Layoun arboreta (region of Kairouan, central Tunisia) in January 2005, afforded essential oils in yields varying from 0.5±0.1 to 5.7±0.5%, dependent on the species. E. sargentii and E. brockwayi provided the highest and the lowest percentage of essential oil amongst all the species examined, respectively. Analysis by GC (RI) and GC/MS allowed the identification of 133 components, representing 92.9–98.8% of the total oil. The contents of the different samples varied according to the species. The main components were 1,8‐cineole, terpinen‐4‐ol, α‐pinene (2), p‐cymene, aromadendrene (1), g...

The essential oil composition of leaves of 60 individual trees of Juniperus oxycedrus L. growing in four locations in Tunisia harvested in three different seasons were investigated by GC and GC/MS. Seventy compounds were identified in the oils, and a relatively high variation in their contents were found. All the oils were dominated by terpenic hydrocarbons, with α‐pinene (27.35–58.03%) as the main component, followed by geranyl acetone (13; 1.96–7.14%), 13‐epimanoyl oxide (16; 1.35–6.95%), and eudesma‐4(15),7‐dien‐1‐ol (11; 1.39–4.18%). The 18 major oil components were processed by hierarchical clustering and principal component analysis (PCA) allowing to establish four groups, one divided into two subgroups, of populations according to the location and season of harvest. Their oils were differentiated by one compound or more, showing a clear seasonal and geographical polymorphism in their chemical composition allowing the identification of specific chemotypes. The pattern of geogr...

The large pine weevil Hylobius abietis (Linnaeus 1758) is the main pest of coniferous seedlings in Europe and causes substantial damage in areas that have been clear-cut or otherwise disturbed. We compared the efficacy of different attractants for the capture of H. abietis adults in white pitfall traps. The field experiment was performed from mid-April to the end of August 2018 at six plots in Central Europe located in spruce stands that had been clear-cut. At each plot, we compared five attractants: one pine twig with ethanol, Hylodor, alpha-pinene + ethanol, turpentine oil and ethanol (separated), and turpentine oil + ethanol (not separated). Traps without attractant served as a control. Six traps for each attractant or control were distributed at each plot. Of the total number of H. abietis adults trapped, 43.3%, 20.5%, 17.9%, 9.8%, 8.5% and 0.5% were captured in traps with pine twigs with ethanol, alpha-pinene, Hylodor, turpentine, oil + ethanol (separated), turpentine oil + eth...

Wood-boring insects, such as Cerambyx welensii Küster, are involved in oak decline in Mediterranean areas. To advance our understanding of the olfactory perception of C. welensii, we recorded electroantennographic (EAG) responses from male and female antennae to 32 tree volatile organic compounds typical of emissions from its main Quercus L. hosts, and also analysed the dose-dependent response. Cerambyx welensii antennae responded to 24 chemicals. Eight odorants elicited the highest EAG responses (normalized values of over 98%): 1,8-cineole, limonene-type blend, β-pinene, pinene-type blend, sabinene, α-pinene, turpentine and (E)-2-hexenal. Cerambyx welensii exhibits a broad sensitivity to common tree volatiles. The high EAG responses to both limonene- and pinene-type blends suggest the detection of specific blends of the main foliar monoterpenes emitted by Q. suber L. and Q. ilex L. (limonene, α- and β-pinene, sabinene and myrcene), which could influence the intraspecific host choic...

Nineteen samples of Rosmarinus officinalis were extracted by steam distillation in a pilot plant and evaluated in terms of chemical compositions and physico-chemical characteristics. The volatile oil yields ranged from 0.37% (1999 harvest) to 0.49% (1998 harvest). Twenty components were identified in the oils. The major components were alpha-pinene (40.55 to 45.10%), 1,8-cineole (17.40 to 19.35%), camphene (4.73 to 6.06%) and verbenone (2.32 to 3.86%). The physico-chemical parameters averaged 0.8887 g/cm³ for specific gravity, 1.4689 for refractive index, and +11.82° for optical rotation, and there were no significant variations in either the chemical or physico-chemical data in the different years.

The chemical composition and antimicrobial activity of the essential oil isolated by steam distillation from Hypericum perforatum L. (St John�s wort) growing wild in western Romania have been studied. The extraction yield was 0.41% (v/w) based on the dry plant material. The essential oil was analyzed by GC�MS, and a total of twenty-two components were identified. The major components were alpha-pinene (30.92%), beta-pinene (18.32%) and caryophyllene (15.26%). The antimicrobial activity of the H. perforatum essential oil was screened using the disk diffusion method against 7 common food-related bacteria and fungus. The analyzed EO possesses strong antimicrobial activity. Klebsiella pneumoniae and Pseudomonas aeruginosa were the most resistant species. The analyzed oil can represent an inexpensive natural source of antiseptic compounds, an alternative to synthetic preservatives.

Volatile constituents of various solvent extracts (n-hexane, CH2Cl2, H2O) of 15 different organs (leaves, flowers, fruits) of five Rhododendron species (Ericaceae) growing in Turkey were trapped with headspace solid-phase microextraction (HS-SPME) technique and analyzed by GC-MS. A total of 200 compounds were detected and identified from organic extracts, while the water extracts contained only traces of few volatiles. The CH2Cl2 extract of the R. luteum flowers was found to exhibit the most diverse composition: 34 compounds were identified, with benzyl alcohol (16.6%), limonene (14.6%) and p-cymene (8.4%) being the major compounds. The CH2Cl2-solubles of R. x sochadzeae leaves contained only phenyl ethyl alcohol. This study indicated appreciable intra-specific variations in volatile compositions within the genus. Different anatomical parts also showed altered volatile profiles. This is the first application of HS-SPME-GC-MS on the volatiles of Rhododendron species.

The essential oils of leaves and twigs of Myrtus communis with black and white fruits were analyzed by GC and GC/MS. The leaves were rich in essential oil (0.77–0.94%) than the twigs (0.05%). More than forty compounds were identified in each leaf essential oils, the major compounds were α-pinene/1,8-cineol with different percent compositions
(33.4/42.4%) and (39.3/33.3%) in M. communis with white and black fruits, respectively. Thirty-eight compounds were identified in the essential oils of the twigs among which the main compounds were p-cymene
(17.7%), α-pinene (10.8%), 1,8-cineol (13.5%), and limonene (10.7%). While the volatile fraction of M. communis leaves having white fruits extracted by HS-SPME was characterized by high content of limonene (almost 29%), those with black fruits were dominated by cis-β-terpineol (ca. 29%). The enantiomeric ratio of monoterpenes present in the headspace of all M. communis samples determined using enantioselective gas chromatography/mass spectrometry showed (+)/(
)-α-pinene ratio close to 95/5% and exclusive presence of (+)-antipode for limonene.

Eucalyptus is a Myrtaceous genus of flowering plants of about 700-800 species, mostly native to Australia. The aim of this work was to study the chemical composition of the essential oilsfrom the leaves, twigs and fruits of Eucalyptus deglupta cultivated in Costa Rica. The essential oils were obtained by hydrodistillation and the chemical composition of the oils wasanalyzed by capillary gas chromatography with a flame detector(GC-FID) and gas chromatography-mass spectrometry (GC-MS) using the retention indices (RI) on a DB-5 type capillary column. A total of 146compounds were identified, accounting for 94.1-96.0% of the total amountof the oils. The major constituents in the leaf oil were α-phellandrene (32.7%), α-pinene (16.8%), p-cymene (12.6%), limonene (5.2%), β-phellandrene (5.0%), (E)-nerolidol (4.4%), and β-pinene (4.0%).The twig oil consisted mainly of α-pinene (37.8%), pcymene (19.6%), and β-pinene (6.3%). The most significant constituents of the fruit oil were αphellandrene...

Speciated particle-phase organic nitrates (pONs) were quantified using online chemical ionization MS during June and July of 2013 in rural Alabama as part of the Southern Oxidant and Aerosol Study. A large fraction of pONs is highly functionalized, possessing between six and eight oxygen atoms within each carbon number group, and is not the common first generation alkyl nitrates previously reported. Using calibrations for isoprene hydroxynitrates and the measured molecular compositions, we estimate that pONs account for 3% and 8% of total submicrometer organic aerosol mass, on average, during the day and night, respectively. Each of the isoprene- and monoterpenes-derived groups exhibited a strong diel trend consistent with the emission patterns of likely biogenic hydrocarbon precursors. An observationally constrained diel box model can replicate the observed pON assuming that pONs (i) are produced in the gas phase and rapidly establish gas-particle equilibrium and (ii) have a short ...

The Rosemary (Rosmarinus officinalis L.), a well-known medicinal and culinary herb, was studied to compare the terpenic profile of different extracts obtained from dry and fresh herb. There were studied the volatile oil extracted by hydro distillation from dry plant, the hydroalcoholic extracts obtained from fresh respectively dry plant and the glycerol macerate obtained from fresh plant, by GC-MS using headspace injection. The separated compounds were identified using a MS spectra library. The quantitative determination was performed by normalization respectively by calibration curve method for 1,8-cineole, alpha-pinene and D-limonene. The main separated compounds were alpha-pinene, 1,8-cineol, camphene, camphor, D-limonene and cymene. A significant difference was observed between the 4 samples volatile profiles. 1,8-cineole was found major component of the essential oil (VO-21.39%) and glycerol macerate (GM-35.60%), while and α-pinene was detected as the main constituent of the tw...