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PubMed1992

Organic chemicals in the air at Whitaker's Forest/Sierra Nevada Mountains, California.

Air samples from a rural forested site in the Sierra Nevada Mountains were analyzed for volatile organic compounds by a thermodesorption GC/MS technique. Approximately 120 compounds were characterized by their mass spectra, with identification achieved for about 70 of these substances. A high proportion of biogenically emitted substances was found and the concentration of anthropogenic chemicals was relatively low. Twenty-one terpenoid compounds (C10H16 and oxygenated derivatives) and p-cymene were identified, and a single sesquiterpene, tentatively identified as longifolene, was also found. Nopinone (bicyclo[3.1.1]-heptan-2-one, 6,6-dimethyl-) and alpha-pinene oxide (3-oxatricyclo-[4.1.1.02,4]-octane, 2,7,7-trimethyl), both possible pinene degradation products, were among the compounds detected, although it is possible that the observed levels of one or both of these included contributions from formation during the sampling. The strong influence of local vegetative emissions on the composition of the forest air was confirmed by quantitative analysis. Concentrations of single monoterpenes up to 6.8 micrograms m-3 were found, whereas toluene was in the range of 0.3 micrograms m-3. The results from the forest site are compared with urban air samples collected in Riverside, California.

Air Pollutants↗
PubMed1991

Study of the anatomy and of the essential oil of Origanum cordifolium, an endemic of Cyprus.

A study was made of the anatomy and of the essential oil of Origanum cordifolium (Aucher-Eloy et Montbret ex Benth.) Vogel, an endemic subshrub of Cyprus. The anatomical study revealed the typical features of the different parts of the plant. The leaves and the flowers of this aromatic species bear glandular and non-glandular hairs on both sides of the epidermis. Gas chromatography and mass spectrometry showed that the main component of the essential oil of O. cordifolium is alpha-terpineol followed by gamma-terpinene, p-cymene and carvacrol.

Chromatography, Gas↗
PubMed2005

Conformation of DNA modified by monofunctional Ru(II) arene complexes: recognition by DNA binding proteins and repair. Relationship to cytotoxicity.

We analyzed DNA duplexes modified at central guanine residues by monofunctional Ru(II) arene complexes [(eta(6)-arene)Ru(II)(en)(Cl)](+) (arene = tetrahydroanthracene or p-cymene, Ru-THA or Ru-CYM, respectively). These two complexes were chosen as representatives of two different classes of Ru(II) arene compounds for which initial studies revealed different binding modes: one that may involve DNA intercalation (tricyclic-ring Ru-THA) and the other (mono-ring Ru-CYM) that may not. Ru-THA is approximately 20 times more toxic to cancer cells than Ru-CYM. The adducts of Ru-THA and Ru-CYM have contrasting effects on the conformation, thermodynamic stability, and polymerization of DNA in vitro. In addition, the adducts of Ru-CYM are removed from DNA more efficiently than those of Ru-THA. Interestingly, the mammalian nucleotide excision repair system has low efficiency for excision of ruthenium adducts compared to cisplatin intrastrand crosslinks.

Base Sequence↗
PubMed2004

Analysis of volatile secondary metabolites from Colombian Xylopia aromatica (Lamarck) by different extraction and headspace methods and gas chromatography.

Hydrodistillation (HD), simultaneous distillation-solvent extraction (SDE), microwave-assisted hydrodistillation (MWHD), and supercritical fluid (CO2) extraction (SFE), were employed to isolate volatile secondary metabolites from Colombian Xylopia aromatica (Lamarck) fruits. Static headspace (S-HS), simultaneous purge and trap (P&T) in solvent (CH2Cl2), and headspace (HS) solid-phase microextraction (SPME) were utilised to obtain volatile fractions from fruits of X. aromatica trees, which grow wild in Central and South America, and are abundant in Colombia. Kováts indices, mass spectra or standard compounds, were used to identify more than 50 individual components in the various volatile fractions. beta-Phellandrene was the main component found in the HD and MWHD essential oils, SDE and SFE extracts (61, 65, 57, and ca. 40%, respectively), followed by beta-myrcene (9.1, 9.3, 8.2 and 5.1%), and alpha-pinene (8.1, 7.3, 8.1 and 5.9%). The main components present in the volatile fractions of the X. aromatica fruits, isolated by S-HS, P&T and HS-SPME were beta-phellandrene (53.8, 35.7 and 39%), beta-myrcene (13.3, 12.3 and 10.1%), p-mentha-1(7),8-diene (7.1, 10.6 and 10.4%), alpha-phellandrene (2.2, 5.0 and 6.4%), and p-cymene (2.2,4.7 and 4.4%), respectively.

Annonaceae↗
PubMed2004

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)-beta-ocimene (29.6%), gamma-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.

Apiaceae↗
PubMed2005

Application of artificial neural network on mono- and sesquiterpenes compounds determined by headspace solid-phase microextraction-gas chromatography-mass spectrometry for the Piedmont ricotta cheese traceability.

Mono- and sesquiterpenes were used for the traceability of a typical Piedmont (Italy) mountain ricotta cheese produced by nine mountain farms. For each farm a sample of ricotta cheese was collected every 7 days during mountain grazing and analysed using headspace solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). Obtained results showed the presence of about 20 monoterpenes (above all alpha-pinene, beta-pinene, camphene, p-cymene, beta-myrcene and limonene) and about 15 sesquiterpenes such as alpha-caryophyllene, alpha-copaene and 9-epi-caryophyllene. Despite a wide concentration variability due to the stages of plant development and the pastured area, there are not able differences between the ricotta cheeses analysed so it is possible with the artificial neural network (ANN) technique to distinguish between different mountain farms.

Cheese↗
PubMed2005

Analysis of the essential oil from aerial parts of Eupatorium cannabinum subsp. corsicum (L.) by gas chromatography with electron impact and chemical ionization mass spectrometry.

Eupatorium cannabinum subsp. corsicum (L.), an aromatic plant, is an endemic subspecies from Corsica. The essential oil from aerial parts of E. cannabinum subsp. corsicum was studied by GC, GC/MS and 13C NMR. One hundred and forty-seven components were identified representing 93.6% of the total amount. The main constituents are germacrene D (28.5%), alpha-phellandrene (19.0%) and para-cymene (5.2%). A particularity of this essential oil is the presence of monoterpene esters derived from nerol, lavandulol, borneol, thymol and 8,9-dehydrothymol. These compounds have been investigated using GC/MS in different ionization modes like electron impact (EI), positive chemical ionization (PCI) and negative chemical ionization (NCI).

Esters↗
PubMed2005

Analysis of the essential oil composition of eight Anthemis species from Greece.

The volatile composition of eight Anthemis species has been studied. The essential oils were obtained by hydrodistillation in a modified Clevenger-type apparatus, and their analyses were performed by GC and GC-MS. Identification of the substances was made by comparison of mass spectra and retention indices with literature records. A total of 284 different compounds were identified and significant qualitative and quantitative differences and similarities were observed among the samples. The main constituents of the investigated populations of each taxon have been revealed as follows: A. altissima: (-)-linalool, trans-caryophyllene, cis-chrysanthenyl acetate; A. auriculata: spathulenol, trans-caryophyllene, beta-eudesmol; A. chia: cis-chrysanthenyl acetate, trans-caryophyllene, germacrene-d; A. cotula: germacrene-d, spathulenol A. tinctoria: spathulenol, (-)-caryophyllene oxide, T-cadinol; A. melanolepis: p-cymene, chrysanthenone, trans-verbenol, (-)-caryophyllene oxide; A. tomentosa: (-)-linalool, 1,8-cineole; A. werneri subsp. werneri: nopol, terpineol-4, trans-caryophyllene. Sesquiterpene hydrocarbons were shown to be the main group of constituents of all taxa.

Anthemis↗
PubMed2004

Essential oils: their antibacterial properties and potential applications in foods--a review.

In vitro studies have demonstrated antibacterial activity of essential oils (EOs) against Listeria monocytogenes, Salmonella typhimurium, Escherichia coli O157:H7, Shigella dysenteria, Bacillus cereus and Staphylococcus aureus at levels between 0.2 and 10 microl ml(-1). Gram-negative organisms are slightly less susceptible than gram-positive bacteria. A number of EO components has been identified as effective antibacterials, e.g. carvacrol, thymol, eugenol, perillaldehyde, cinnamaldehyde and cinnamic acid, having minimum inhibitory concentrations (MICs) of 0.05-5 microl ml(-1) in vitro. A higher concentration is needed to achieve the same effect in foods. Studies with fresh meat, meat products, fish, milk, dairy products, vegetables, fruit and cooked rice have shown that the concentration needed to achieve a significant antibacterial effect is around 0.5-20 microl g(-1) in foods and about 0.1-10 microl ml(-1) in solutions for washing fruit and vegetables. EOs comprise a large number of components and it is likely that their mode of action involves several targets in the bacterial cell. The hydrophobicity of EOs enables them to partition in the lipids of the cell membrane and mitochondria, rendering them permeable and leading to leakage of cell contents. Physical conditions that improve the action of EOs are low pH, low temperature and low oxygen levels. Synergism has been observed between carvacrol and its precursor p-cymene and between cinnamaldehyde and eugenol. Synergy between EO components and mild preservation methods has also been observed. Some EO components are legally registered flavourings in the EU and the USA. Undesirable organoleptic effects can be limited by careful selection of EOs according to the type of food.

Anti-Bacterial Agents↗
PubMed2025

Insights into dill (Anethum graveolens) flavor formation via integrative analysis of chromosomal-scale genome, metabolome and transcriptome.

INTRODUCTION: Dill (Anethum graveolens) is a significant medicinal herb belonging to the Apiaceae family. Owing to its high levels of volatile organic compounds (VOCs), dill is commonly utilized for essential oil extraction and medicine purpose. However, the biosynthesis of the crucial VOC in dill remains obscure. OBJECTIVES: Identify the key VOCs related to the flavor formation in dill and dissect the regulatory mechanism of their synthesis. METHODS: The dill chromosomal-level genome was constructed by PacBio HiFi, Hi-C, and BGISEQ second generation sequencing and assembly. The VOCs in dill leaves were identified through GC-MS. The potential mechanism involved in regulating the VOC accumulation in dill flavor formation was analyzed by multi-omics analysis. RESULTS: A 1.17 Gb chromosome-scale genome of dill with a contig N50 of 10.78 Mb was constructed. A total of 46,538 genes were annotated across 11 assembled chromosomes. Comparative genomics analysis suggested that transposable element insertions, especially LTR-Gypsy, have contributed to the evolution and expansion of the dill genome. The flavor formation of dill was mainly attributed to terpenoids, especially α-phellandrene, β-ocimene, and o-cymene. The contribution of expansion and replication of terpenoid synthesis pathway genes, especially terpene synthase (TPS), to the abundant terpenoid production of dill was identified. Differential gene expression patterns observed at various developmental stages and tissues provided key candidate genes for the regulation of terpenoid synthesis, as well as transcription factors. The different accumulation of esters and aromatics also affected the flavor formation of dill. The key genes implicated in the synthesis of anethole, namely AIS and AMT were further identified. CONCLUSION: This study constructed the chromosome level genome and identified the main VOCs and related key genes in flavor formation of dill, shedding lights on our understanding of terpenoid biosynthesis but also offered guidance for future genetic research on molecular breeding in Anethum graveolens.

Transcriptome↗
PubMed2004

In vitro biological activity and essential oil composition of four indigenous South African Helichrysum species.

Helichrysum species are used widely to treat various medical conditions. In this study, the anti-microbial, anti-oxidant (DPPH assay) and anti-inflammatory activity (5-lipoxygenase assay) of Helichrysum dasyanthum, Helichrysum felinum, Helichrysum excisum and Helichrysum petiolare were investigated. The essential oil compositions of these species were determined. The acetone and methanol extracts as well as the essential oils exhibited activity against Gram-positive bacteria, while both the methanol and acetone extracts of all four species were active in the anti-oxidant assay. The essential oils, on the other hand, displayed activity in the 5-lipoxygenase assay, which was used as an indication of anti-inflammatory activity. Two extracts exhibited promising activity in the anti-microbial assay, the acetone extract of Helichrysum dasyanthum with a MIC value of 15.63 microg/ml and the methanol extract of Helichrysum excisum with a MIC value of 62.5 microg/ml. The acetone extract of Helichrysum dasyanthum was the most active free radical scavenger in the DPPH assay (IC(50) of 9.53 microg/ml) while values for the anti-inflammatory activity of the essential oils ranged between 25 and 32 microg/ml. The essential oil compositions of three species (Helichrysum dasyanthum, Helichrysum excisum and Helichrysum petiolare) were dominated by the presence of monoterpenes such as alpha-pinene, 1,8-cineole and p-cymene. In the oil of Helichrysum felinum, monoterpenes were largely absent. Its profile consisted of a variety of sesquiterpenes in low concentrations with beta-caryophyllene dominating.

Helichrysum↗
PubMed2005

Chemical composition and biological activities of essential oil from the leaves of Sesuvium portulacastrum.

Sesuvium portulacastrum has long been used as a remedy for fever and scurvy. Hydrodistillation was used to extract the essential oil from the fresh leaves of Sesuvium portulacastrum. The essential oil yield obtained was 0.15%. Using GC-MS analysis, alpha-pinene, camphene, beta-pinene, alpha-terpinene, O-cymene, limonene, 1,8-cineole, alpha-terpinene, bornyl acetate, tridecane, trans-caryophyllene and alpha-humulene were identified. The hole plate diffusion method was used for antibacterial testing. The essential oil exhibited antibacterial activity against Acetobacter calcoacetica, Bacillus subtillis, Clostridium sporogenes, Clostridium perfringens, Escherichia coli, Salmonella typhii, Staphylococcus aureus and Yersinia enterocolitica. The mycelium growth inhibition method was used for the antifungal testing. The oil exhibited antifungal activity against Candida albicans, Aspergillus niger, Aspergillus flavus and Penicillium notatum. Using the beta-carotene, acetone and linoleic acid method for the antioxidant testing, the essential oil showed antioxidant activity threshold of 15.9 mm mean zone of color retention.

Aizoaceae↗
PubMed2006

Phytochemical composition of essential oil from seeds of Zingiber roseum Rosc. and its antispasmodic activity in rat duodenum.

A combination of GC and GC-MS revealed the presence of 60 compounds out of which 47 compounds (96.2% of the oil) were identified in the essential oil of seeds of Zingiber roseum Rosc., the major compounds being alpha-pinene, beta-pinene, limonene, p-cymene, alpha-terpineol and verticiole. The unique feature is the dominant presence of mono- and sesquiterpene hydrocarbons which make about 82% of the oil. The oil showed myorelaxant activity on isolated rat duodenal smooth muscle. The Zingiber roseum seed essential oil (ZRSEO) relaxed both cabachol- and KCl-induced contractile responses with IC(50) of non-significant difference. The results confirm a common mechanism in both the types of action of ZRSEO and suggests a probable inhibitory effect of ZRSEO on influx of Ca(2+) through cell membrane of rat duodenal smooth muscle.

Animals↗
PubMed2006

The formation of ultra-fine particles during ozone-initiated oxidations with terpenes emitted from natural paint.

The formation of secondary products during the ozone-initiated oxidations with biogenic VOCs emitted from natural paint was investigated in this study. Mass spectrometry and infrared spectroscopy measurements have shown that the major components of gas-phase chemicals emitted from natural paint are monoterpenes including alpha- and beta-pinenes, camphene, p-cymene, and limonene. A significant formation of gaseous carbonyl products and nano-sized particles (4.4-168nm) was observed in the presence of ozone. Carboxylic acids were also observed to form during the reactions (i.e. formic acid at 0.170ppm and acetic acid at 0.260ppm). The formation of particles increased as the volume of paint introduced into a reaction chamber increased. A secondary increase in the particle number concentration was observed after 440min, which suggests further partitioning of oxidation products (i.e. carboxylic acids) into the particles previously existing in the reaction chamber. The growth of particles increased as the mean particle diameter and particle mass concentrations increased during the reaction. The experimental results obtained in this study may provide insight into the potential exposure of occupants to irritating chemical compounds formed during the oxidations of biogenic VOCs emitted from natural paint in indoor environments.

Air Pollution, Indoor↗
PubMed2005

Allosteric positive interaction of thymol with the GABAA receptor in primary cultures of mouse cortical neurons.

Thymol is a naturally occurring phenolic monoterpene known for its anti-microbial and anti-oxidant properties. It is used in dental practice and in anaesthetic halothane preparations. Recent studies have reported enhanced GABA(A) receptor-operated chloride channel activity and increased binding affinity of [(3)H]flunitrazepam in the presence of thymol. In the present work, we more closely examined the pharmacological action of thymol on the native GABA(A) receptor by using primary cultures of cortical neurons. Thymol enhanced GABA-induced (5 microM) chloride influx at concentrations lower than those exhibiting direct activity in the absence of GABA (EC(50) = 12 microM and 135 microM, respectively). This direct effect was inhibited by competitive and non-competitive GABA(A) receptor antagonists. Thymol increased [(3)H]flunitrazepam binding (EC(50) = 131 microM) and showed a tendency to increase [(3)H]muscimol binding. These results confirm that thymol is a positive allosteric modulator of the GABA(A) receptor. The thymol structural analogues menthol and cymene, which lack an aromatic ring or a hydroxyl group, did not affect [(3)H]flunitrazepam binding. Using a pharmacophoric model that includes a hydrogen bond donor group as well as an aromatic ring with two aliphatic substituents, we propose to demonstrate the molecular essential features of these compounds to interact with GABA(A) receptors. Thymol (0-1 mM) did not affect cellular viability.

Anesthetics, Intravenous↗
PubMed2006

Anticonflict effects of lavender oil and identification of its active constituents.

The pharmacological effects of lavender oil were investigated using two conflict tests in ICR mice, and then the active constituents were identified. Lavender oil produced significant anticonflict effects at 800 and 1600 mg/kg in the Geller conflict test and at 800 mg/kg in the Vogel conflict test, suggesting that the oil has an anti-anxiety effect. Analysis using GC/MS revealed that lavender oil contains 26 constituents, among which alpha-pinene (ratio, 0.22%), camphene (0.06%), beta-myrcene (5.33%), p-cymene (0.3%), limonene (1.06%), cineol (0.51%), linalool (26.12%), borneol (1.21%), terpinene-4-ol (4.64%), linalyl acetate (26.32%), geranyl acetate (2.14%) and caryophyllene (7.55%) were identified. We examined the effects of linalool, linalyl acetate, borneol, camphene, cineol, terpinen-4-ol, alpha-pinene and beta-myrcene using the Geller and Vogel conflict tests in ICR mice. Cineol, terpinen-4-ol, alpha-pinene and beta-myrcene did not produce any significant anticonflict effects in the Geller test. Linalyl acetate did not produce any significant anticonflict effects in either test. Both borneol and camphene at 800 mg/kg produced significant anticonflict effects in the Geller, but not in the Vogel conflict test. Linalool, a major constituent of lavender oil, produced significant anticonflict effects at 600 and 400 mg/kg in the Geller and Vogel tests, respectively, findings that were similar to those of lavender oil. Thus, we concluded that linalool is the major pharmacologically active constituent involved in the anti-anxiety effect of lavender oil.

Animals↗
PubMed2006

Critical components of odors in evaluating the performance of food waste composting plants.

The current Taiwan government policy toward food waste management encourages composting for resource recovery. This study used olfactometry, gas chromatography-mass spectrometry (GC-MS) and gas detector tubes to evaluate the ambient air at three of the largest food waste composting plants in Taiwan. Ambient air inside the plants, at exhaust outlets and plant boundaries was examined to determine the comprehensive odor performance, critical components, and odor elimination efficiencies of various odor control engineering. Analytical results identified 29 compounds, including ammonia, amines, acetic acid, and multiple volatile organic compounds (VOCs) (hydrocarbons, ketones, esters, terpenes and S-compounds) in the odor from food waste composting plants. Concentrations of six components--ammonia, amines, dimethyl sulfide, acetic acid, ethyl benzene and p-Cymene--exceeded human olfactory thresholds. Ammonia, amines, dimethyl sulfide and acetic acid accounted for most odors compared to numerous VOCs. The results also show that the biotrickling filter was better at eliminating the concentrations of odor, NH(3), amines, S-compounds and VOCs than the chemical scrubber and biofilters. All levels measured by olfactometry at the boundaries of food waste composting plants (range, 74-115 Odor Concentration (OC)) exceeded Taiwan's EPA standard of 50 OC. This study indicated that the malodor problem continued to be a significant problem for food waste recovery.

Air Pollutants↗
PubMed2001

Monoterpenic and norisoprenoidic glycoconjugates of Vitis vinifera L. cv. Melon B. as precursors of odorants in Muscadet wines.

The volatile monoterpenic and norisoprenoidic compounds released by glycosidase enzyme hydrolysis of C18 reversed-phase isolates from the juice of Vitis vinifera L. cv. Melon B. have been qualitatively and quantitatively determined using GC-MS and GC-FID. The components analyzed were broadly similar to those previously reported for other varieties but the level of bound p-menth-1-en-7,8-diol was higher in this cultivar. Then the monoterpenic and norisoprenoidic volatiles released from the same glycosidic extracts under mild acid conditions, mimicking wine aging conditions, have been analyzed using GC-Olfactometry and GC-MS. The most odorous compounds detected were p-cymene, terpinen-4-ol, cis- and trans-vitispiranes, 1,6,6-trimethyl-1,2-dihydronaphtalene (TDN), beta-damascenone and riesling acetal. To assess their potential levels in corresponding wines after ageing, most of these odorants were generated by harsh acid hydrolysis from the precursors extracts and quantitatively determined using SPME and GC-MS/MS. For the development and application of this analysis, the odorants not commercialy available were synthesized. The total amounts of norisoprenoidic odorants generated by acid hydrolysis of the glycosidic extracts were shown to be proportional to the total amounts of these precursors.

Gas Chromatography-Mass Spectrometry↗