Monoterpene Fraction Research Articles

Chemical composition and antimicrobial activity of the essential oil of Ocimum gratissimum L. growing in Eastern Kenya

Hydro-distilled volatile oils from the leaves of Ocimum gratissimum L. (Lamiaceae) from Meru district in Eastern Kenya were analysed by gas chromatography-mass spectrometry (GC-MS) and also evaluated for antimicrobial activity. The oil was dominated by monoterpens which accounted for 92.48%. This monoterpene fraction was characterized by a high percentage of eugenol (68.8%). The other major monoterpenes were methyl eugenol (13.21%), cis-ocimene (7.47%), trans-ocimene (0.94%),
-pinene (1.10%) and camphor (0.95%). The sesquiterpenes present in fairly good amounts were germacrene D (4.25%) and trans-caryophyllene (1.69%). The minor sesquiterpenes were -farnesene (0.85%) and
- bisabolene (0.74%). The antimicrobial activities of the essential oils were evaluated against both Gram positive (Staphylococcus aureus, Bacillus spp.) and Gram negative (Escherichia coli, Pseudomonas aeruginosae, Salmonella typhi, Klebisiella pneumoniae, Proteus mirabilis) bacteria and a pathogenic fungus Candida albicans. The oil had pronounced antibacterial and antifungal activities on all the microbes.

Chemical composition of Pinus silvestris essential oil from contaminated areas

The chemical composition of Pinus silvestris essential oil from contaminated areas was studied. An apparent effect of radionuclides and toxic elements on the biosynthesis of terpenoids in common pine essential oil was found. Increasing contamination apparently increased the content of sesquiterpenes and O-containing substances and decreased the content of monoterpenes in the essential oil. The contents of α-pinene, camphene, and limonene increased and those of 3-carene, terpinolene, and β-pinene decreased in the monoterpene fraction.

Composition of the essential oils from the leaves of nine Pinus species and the cones of three of Pinus species

AbstractThe essential oils from leaves of Pinus koraiensis, P. merkusii, P. palustris, P. parviflora, P. petula, P. ponderosa, P. pumila, P. rigida and P. rudis and cones of P. densiflora, P. rigida and P. taeda were investigated by GC–MS. Yields of the oils were 0.08–2.33 (w/w). α‐Pinene (0.2–51.8%) and β‐pinene (0.1–38.2%) were contained in both the leaf and cone oils of Pinus species. The monoterpene fractions of Pinus leaf oils comprised mainly pinanes and menthanes. Pinanes were present in greater amounts than menthanes in the leaf oils of all the species except P. petula. The leaves of P. pumila contained caranes as major components, whereas those of P. parviflora contained camphanes as major components. As for sesquiterpenes in the leaf oils, caryophyllane and/or the cadinane group were the major components. The leaf oils of P. merkusii, P. petula and P. rudis contained larger amounts of caryophyllanes than those of the cadinane group. The sesquiterpenes of these three species were mainly caryophyllanes, while in the sesquiterpene fraction of other Pinus species the content of the cadinane group was larger than that of caryophyllanes. Concerning cone oils, P. rigida and P. taeda cones were mainly composed of monoterpenes, while P. densiflora contained sesquiterpenes as the main components. Copyright © 2006 John Wiley & Sons, Ltd.

Essential Oil Composition of Pimpinella barbata (DC.) Boiss. from Iran

The essential oil composition from the aerial parts of Pimpinella barbata (DC.) Boiss. (Apiaceae) at full-flowering stage from Iran was studied by GC and GC/MS. A total of 32 compounds have been identifed, accounting for 97.0% of the total oil. Analysis of the oil showed that the oil of P. barbata was rich in a phenylpropanoid fraction, in which methyl eugenol (34.0%) and elemicin (6.9%) were the two main constituents. The main compouds of monoterpene fraction were limonene (26.6%), sabinene (6.7%) and perillaldehyde (5.2%).

Volatile Constituents from the Aerial Parts of Salvia angulata H.B.K. of Venezuela

The essential oil isolated by hydrodistillation from the aerial parts of Salvia angulata H.B.K., (Lamiaceae) collected from southwestern Venezuela, was analyzed by GC and GC/MS. Among the 22 identified compounds, the major components were the sesquiterpenes hydrocarbons which made up 79.8% of the oil, with β-caryophyllene (27.7%), germacrene D (19.5%) and bicyclogermacrene (18.3%) as the most abundant ones. Oxygenated sesquiterpenes made up 14.2% of the oil, while the monoterpene fraction was only 3.3%. As far as we know, this is the first report on S. angulata essential oil.

Defensive Secretion Components of the Host Parastizopus armaticeps as Kairomones for the Cleptoparasite Eremostibes opacus

The subsocial tenebrionid Parastizopus armaticeps Pér. is parasitized by the closely related Eremostibes opacus Koch (Coleoptera: Tenebrionidae). We found that the pygidial defensive secretions of both species are similar and contain a mixture of 1,4-benzoquinones, 1-alkenes, and monoterpene hydrocarbons. The 1-alkenes are dominated by 1-undecene, with admixtures of 1-tridecene in both species and 1-pentadecene in P. armaticeps only. Methyl- and ethyl-1,4-benzoquinone are the major quinones of the secretions of both species. The monoterpene fractions consist of (-)-alpha-pinene, (-)-camphene, sabinene, (-)-beta-pinene, and (-)-limonene. Volatiles trapped with Porapak Q at the entrance to the breeding burrows of P. armaticeps were identified as components of the defensive secretion. However, in contrast to the secretion, the 1,4-benzoquinones were almost completely absent in the volatiles. Bioassays investigating attraction showed that the cleptoparasite E. opacus was drawn to the monoterpene hydrocarbons, produced by P. armaticeps, and deterred by the 1,4-benzoquinones. The 1-alkenes had no effect. Among the monoterpenes, only (-)-camphene was attractive to E. opacus. This is one of the rare cases of chemical exploitation of defensive allomones, and the first based on odor homology. We have drawn an evolutionary scenario including various functional changes in the defensive secretion compounds, leading to the kairomonal exploitation.

Asterella africana (Mont.) A. Evans grown on Madeira and in mainland Portugal: morphological data and composition of the essential oil

AbstractAsterella africana (Mont.) A. Evans was collected on Madeira and in mainland Portugal at distinct locations and collection dates. The morphology of this marchantioid liverwort was analysed by scanning electron microscopy. The Madeiran A. africana showed a large variability in spore and elater dimensions, but marked differences have not been found in most of the morphological characters. Essential oil samples isolated by distillation‐extraction were analysed by GC and GC–MS. These samples were dominated by the monoterpene fraction (79–84%); the sesquiterpene and non‐terpenoid fractions amounted to 1–2% and 4–8%, respectively. Myrtenyl acetate (30–42%) and α‐pinene (10–17%) were the dominant components of all A. africana oil samples; the percentage contents of the other main components differed. Copyright © 2006 John Wiley & Sons, Ltd.

Analysis of Indian Tea Tree (Melaleuca alternifolia cheel.) Essential Oil a Vital Aromatherapy Oil

The hydro distilled essential oil from the freshly cut leaves and branches of Melaleuca alternifolia Cheel. grown in India was analyzed by capillary GC and GC-MS. The leaf oil was found to contain 33 components (99.5%) of which 21 were completely identified, 6 were tentatively identified while as one remained unknown. Quantitatively the oil was characterized by a high percentage of monoterpene fraction amounting to about 67%, dominated by oxygenated monoterpenes (59.3%). Terpinen-4-ol (47.7%) was the main component followed by neo-dihydrocarveol (6.3%) and 1,8-cineole (5.3%). The monoterpene hydrocarbon fraction (9.3%) consisted mainly of ρ-cymene (7.3%). The sesquiterpene fraction (16.2%) consists mainly of β-caryophyllene and globulol (3% each).

Chemical polymorphism of populations of Thymus caespititius grown on the islands Corvo, Flores, São Miguel and Terceira (Azores) and on Madeira, assessed by analysis of their essential oils

The composition of the essential oils isolated from 24 populations of Thymus caespititius collected on Corvo, Flores, São Miguel and Terceira (Azores) and on Madeira were studied by GC and GC–MS. All the oil samples analysed were dominated by their monoterpene fraction (66–89%). In the Azorean populations, the proportion of the oxygenated monoterpenes (51–79%) was higher than that of the monoterpene hydrocarbons (8–27%). In contrast, the monoterpene hydrocarbons and the oxygenated monoterpenes represented 35–44 and 42–43%, respectively, of the total oils from the populations grown on Madeira. Cluster analysis of the identified components with a concentration ≥1% grouped the oils into three main clusters that corresponded with their main components: carvacrol (41–65%), thymol (35–51%) and α-terpineol (33–37%). Although the populations collected on Madeira were grouped in the same cluster, the chiral analysis of sabinene, terpinen-4-ol and α-terpineol showed that there was a clear chemical polymorphism. Actually, in the oils from two populations (−)-sabinene, (−)-terpinen-4-ol and (+)-α-terpineol were the predominant enantiomers while in that from the third population an opposite ratio was found. The chemical polymorphism of the essential oils from T. caespititius may result either from the genetic variability of the populations or from the influence of edaphic factors.

Origanum glandulosum Desf. grown wild in Algeria: essential oil composition and glycosidic bound volatiles

The essential oils, isolated by distillation–extraction (DE) and hydrodistillation (H) for different extraction periods, from the aerial parts of Origanum glandulosum collected at the flowering phase in Algeria, were analysed by GC and GC-MS. The oil yields determined by hydrodistillation attained 1.8% (v/w) and 2.7% (v/w) when extracted for 10 min and 3 h, respectively. The essential oils were dominated by the monoterpene fraction (DE 95–96% and H 86–97%), carvacrol being the main component of all oils (49–57 and 45–47% for DE and H oils, respectively). The other main components (>5%) were γ-terpinene (DE 17–13 and H 18–13%), p-cymene (DE 14–10 and H 17–11%) and thymol (DE 7 and H 5–7%). The composition of the glycosidic bound volatiles showed very little resemblance to the corresponding essential oil fraction. Thirteen components were detected in the glycosidic bound volatiles, only six of which were also present in the essential oil. The oxygen-containing monoterpenes were the dominant fraction (75–97%) of the glycosidic bound volatiles, but the main component was dependent on the extraction period and not on the isolation procedure. Carvacrol (71% for DE and 61% for H) dominated the 10 min distillation, whereas thymoquinone, which was not present on the essential oil, was the dominant component in the 3 h distillation (79% for DE and 59% for H). Copyright © 2004 John Wiley & Sons, Ltd.

Volatile components of the aerial parts ofArtemisia pontica L. grown in Bulgaria

The volatile components of the aerial parts of Artemisia pontica L., obtained through hydrodistillation, were investigated by GC and GC-MS. The oxygen-containing monoterpene fraction dominated (36.7%), while 1.8-cineole (14.1%) and camphor (13.9%) were the main components. Other relatively abundant components in this fraction were terpinen-4-ol (3.0%), sabina ketone (1.5%), dehydro sabina ketone (1.3%), and Z-sabineini-hydrate. In the sesquiterpene hydrocarbon fraction (1.0%) 7H-alpha-silphiperfol-5-ene (0.7%), together with silphin-1-ene (trace) and two other silphiperfolene isomers could be identified. 7H-alpha-Silphiperfol-5-ene was identified for the first time in A. pontica. In the oxygen-containing sesquiterpene hydrocarbon fraction (22.6%) a number of silphiperfolene isomers were also found, e.g. silphiperfol-5-en-3-ol C (9.7%), silphiperfol-5-en-3-one B (0.7%), silphiperfol-5-en-3-yl acetate A (1.0%). Most probably, silphiperfol-5-en-3-ol D (2.5%) and silphiperfol-5-en-3-one A were also present. Copyright (c) 2004 John Wiley & Sons, Ltd

Volatile constituents of fourHexachlamys species growing in south Brazil

The essential oils of the fresh leaves of Hexachlamys edulis, H. hamiltonii, H. humilis and H. itatiaiensis were obtained by hydrodistillation and analyzed by GC-FID and GC-MS. Sixty-seven compounds were identified. H. itatiaiensis oil was characterized by large amounts of the monoterpene hydrocarbon α-pinene (22.0%). The oil from H. hamiltonii was shown to be quite distinct from the other species, in which (E)-nerolidol (34.3%), an acyclic sesquiterpene, was the major compound. In the monoterpene fraction limonene (11.3%) was the most representative. In the oil from H. edulis and H. humilis there was a predominance of sesquiterpenes, of which β-selinene (16.1%), β-caryophyllene (8.3%) and δ-cadinene (8.3%) were the most abundant compounds for H. edulis oil, while H. humilis oil was composed mainly of bicyclogermacrene (8.6%), spathulenol (8.1%) and α-cadinol (9.1%). Copyright © 2005 John Wiley & Sons, Ltd.

Antioxidative activity of the essential oils of Thymus sipyleus subsp. sipyleus var. sipyleus and Thymus sipyleus subsp. sipyleus var. rosulans

The aim of present study was to compare the antioxidant potential of two Thymus species on the basis of the chemical compositions of oils obtained by hydrodistillation. In the case of Thymus sipyleus subsp. sipyleus var. sipyleus, 71 compounds were identified representing the 92.5% of the total oil. The major constituents of the oil were described as borneol (11.2%), α-muurolol (9.2%), β-caryophyllene (7.6%), geranial (7.3%) and neral (5.4%). On the other hand, 47 compounds were identified representing 98.7% of the oil of Thymus sipyleus subsp. sipyleus var. rosulans. This oil is characterised by the high monoterpene fraction (94.0%) and especially by the presence of the phenolic carvacrol (58.1%), thymol (20.5%) and their precursors p-cymene (4.1%) and γ-terpinene (4.4%). The oils were also subjected to screening for their possible antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene/linoleic acid assays. In the first case, the free radical scavenging activity of the essential oil of T. sipyleus subsp. sipyleus var. rosulans was superior to var. sipyleus oil (IC 50=220 ± 0.5 and 2670 ± 0.5 μg/ml, respectively). In the case of linoleic acid system, oxidation of linoleic acid was effectively inhibited by T. sipyleus subsp. sipyleus var. rosulans (92.0%), while the var. sipyleus oil had no activity. In the latter case, the linoleic acid inhibition rate of var. rosulans oil is close to the synthetic antioxidant BHT (96.0%).

Essential oil composition of the leaves and stems of Meum athamanticum Jacq., from Spain

The essential oil of the leaves and stems of Meum athamanticum Jacq., has been extracted by steam distillation and analysed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC–MS). The monoterpene fraction was predominant while the sesquiterpene one was practically absent. The principal constituents have been identified as ( E)-β-ocimene (29.6%), γ-terpinene (17.9%), terpinolene (17.0%) and p-cymene (9.7%). Our results show that the chemical composition of the essential oil obtained of the leaves and stems of M. athamanticum from Spain is different to that obtained from plants of Germany, Italy and France.

Essential Oils from Eugenia Species—Part VII: Sections Phyllocalyx and Stenocalyx

The chemical composition of the leaf oils obtained by hydrodistillation of eight Eugenia species, collected in southern Brazil, was analyzed by GC and GC/MS. Eugenia speciosa oil is characterized by large amounts of monoterpene hydrocarbons with α-pinene (47.3%) and limonene (23.0%) as major constituents, while E. cuprea oil is composed of 78.6% sesquiterpenes. Spathulenol (12.1%) was the major component, followed by β-caryophyllene (9.2%) and caryophyllene oxide (8.7%). Eugenia arenosa was dominated by the acyclic sesquiterpene, farnesyl acetate (70.4%) and aromadendrene (11.7%). Eugenia brasiliensis, E. multicostata, E. sulcata and E. xiriricana oils possessed very similar chemical compositions. In the monoterpene fraction, α- and β-pinene were the major components (a total of 40.7%, 23.4%, 35.9% and 21.9%, respectively), while for E. pitanga (E)-β-ocimene (10.5%) was the major component. For the sesquiterpene fraction, spathulenol and globulol were the major components (a total of 10.5%, 19.4%, 18.8% and 24.0%, respectively). In contrast, the oil of E. pitanga was characterized in this fraction by germacrene D and bicyclogermacrene (29.3% and 22.4%, respectively).

Characterization of geraniol synthase from the peltate glands of sweet basil.

The monoterpene fraction of the lemon-scented sweet basil (Ocimum basilicum) cv Sweet Dani consists mostly of citral (a mixture of geranial and neral), with lower levels of geraniol and nerol. These compounds are stored in the peltate glands found on the leaf epidermis. Younger leaves, which have a higher density of such glands, also have a higher content of monoterpenes than older leaves. Geraniol synthase (GES) activity, generating geraniol from geranyl diphosphate, was shown to be localized exclusively or almost exclusively to glands. GES activity resides in a homodimeric protein that was purified to near homogeneity. Basil GES requires Mn2+ as a divalent metal cofactor for activity and produces only geraniol from geranyl diphosphate. Km values of 21 and 51 microM were obtained for geranyl diphosphate and Mn2+, respectively. In the presence of 18O-labeled water, GES catalyzed the formation of 18O-geraniol from geranyl diphosphate, indicating that the reaction mechanism of GES is similar to that of other monoterpene synthases and is different from the action of phosphatases. A GES cDNA was isolated based on analysis of a glandular trichome expressed sequence tag database, and the sequence of the protein encoded by this cDNA shows some similarity to sequences of other terpene synthases. The expression of the GES cDNA in Escherichia coli resulted in a protein with enzymatic activity essentially identical to that of plant-purified GES. RNA gel-blot analysis indicated that GES is expressed in glands but not in leaves of basil cv Sweet Dani, whose glands contain geraniol and citral, and not in glands or leaves of another basil variety that makes other monoterpenes but not geraniol or citral.

Chemical polymorphism of the essential oils from populations of Thymus caespititius grown on the islands Pico, Faial and Graciosa (Azores).

The compositions of the essential oils isolated from the aerial parts of 11 populations of Thymus caespititius collected during the flowering phase on Pico, Faial and Graciosa (Azores) were studied by GC and GC-MS. The monoterpene fraction was dominant in all the oils analysed (55-90%) and consisted mainly of oxygen-containing compounds (44-79%). Sesquiterpenes represented an important fraction of the oils from the populations grown on Graciosa (13-28%). In contrast, this fraction was rather small in the oils from the populations grown on Pico and Faial (6-11%). Despite this, oxygen-containing compounds (4-18%) were always dominant. Cluster analysis of all identified oil components grouped the oils into three main clusters that corresponded with their main components. The oils from the 11 populations studied showed a clear chemical polymorphism that, in some cases, was more evident among populations growing on the same island than among those from different islands.

Patterns of variation and correlation in the monoterpene composition of xylem oleoresin within populations of ponderosa pine

Monoterpenes are important defensive chemicals that may experience diversifying selection from diverse herbivore assemblages. It is thus important to understand what trade-offs exist in the naturally occurring variation in monoterpene profiles. We measured the absolute concentration (mg/mL) of nine monoterpenes in the xylem resin of ponderosa pine from two populations. The size of the total monoterpene pool exhibited continuous (unimodal) variation. α-pinene, β-pinene and Δ-3-carene account for the bulk of this pool, and in both populations, these three monoterpenes show a discontinuous pattern of variation, such that each individual tree could be assigned to one of five characteristic chemotypes. Moreover, the absolute concentrations of these monoterpene fractions are negatively correlated across individuals in both populations, such that an increase in the concentration of any one is correlated with a decrease in the total pool of all the remaining monoterpenes. The use of absolute concentrations rather than relative amounts demonstrates that such correlations are not a statistical artifact of compositional data. Taken together, these observations suggest that while the size of the total monoterpene pool is constrained, and is likely influenced by many genes and environmental factors, naturally occurring variation in the allocation of this pool to competing monoterpene fractions is controlled by relatively few genes. Such allocational trade-offs may place a constraint on the response of populations to selection by multiple herbivore species

Volatile components from Anthriscus sylvestris (L.) Hoffm.

The volatile components of fresh leaves and roots from Anthriscus sylvestris (L.) Hoffm., obtained through hydrodistillation, were analysed by GC and GC–MS. This was compared to dichloromethane extracts of both fresh and dried leaf and root material. The monoterpene fraction (69–70%) dominated, while β-phellandrene (39–45%) was the main component in both the leaf and the root oil. Other components in the leaf oil were β-myrcene (17%), sabinene (6.2%), Z-β-ocimene (5.4%) and benzene acetaldehyde (4.1%). In the roots we found Z-β-ocimene (16.9%) and α-pinene (4.6%) as other major components. These principle constituents of both essential oils were also present in the dichloromethane extracts of the fresh and dried leaves and the roots, although in much smaller percentages. Comparing hydrodistillation of fresh plant material with a dichloromethane extract, the latter yielded a considerably lower amount of constituents. In addition, air drying and freeze drying resulted in a significant loss of volatile constituents as compared to fresh material (dichloromethane extract).

Essential oils from micropropagated plants of Lavandula viridis.

The essential oils of Lavandula viridis were analysed by GC and GC-MS. Comparisons were made between three types of plant material from the same clone: field-grown plant, in vitro shoot cultures and micropropagated plants of the same clone. The most common components usually found in lavender oils were present in the oil samples analysed and more than 45 constituents were identified, representing more than 80% of the essential oil. The essential oils analysed consisted mainly of monoterpenes (75.4-76.3%), where oxygenated and hydrocarbons identified ranged from 41.8 to 57.3% and 18.1 to 34.2%, respectively. The major components found were 1.8-cineole (18.2-25.1%), camphor (9.1-15.7%), alpha-pinene (8.8-14.1%), borneol (4.1-4.8%), beta-pinene (1.2-5.6%), delta 3-carene (1.0-6.5%) and alpha-terpineol (0.8-4.2%). The monoterpene fraction of the in vitro shoot cultures showed different relative amounts of hydrocarbons and oxygenated components in relation to the parent plant and to micropropagated plants. In the sesquiterpene hydrocarbon fraction of the oil samples analysed (6.1-8.2%), 7-epi-alpha-selinene (1.6-4.8%) was the most important component and the oxygenated sesquiterpenes were found in small amounts (1.1-1.7%). The essential oils from field-grown plants of L. viridis, when compared with those obtained from in vitro shoot cultures or micropropagated plants of the same clone, demonstrated that the same major components were found without significant compositional variations.