Chemical variability in the essential oil of Hyptis suaveolens

The essential oils of Hyptis suaveolens plants collected from 11 localities of the Brazilian Cerrado region were investigated by GC-MS. Sabinene, limonene, biclyclogermacrene, beta-phellandrene and 1,8-cineole were the principal constituents. The results were submitted to principal component and chemometric cluster analysis which allowed three groups of essential oils to be distinguished with respect to the content of p-mentha-2,4(8)-diene, limonene/beta-phellandrene/gamma-terpinene and germacrene D/bicyclogermacrene. In patterns of geographic variation in essential oil composition indicated that the sesquiterpenes are mainly produced in the samples grown at lower latitudes.     

A Study on Chemical Components of Essential Oils from Citrus bergamia and Its Close Relatives and Its Taxonomy

Citrus bergamia Risso. is a rare perfumery plant. Taxonomists have different views on the taxonomy of C. bergamia. Chemical components of leaf and peel essential oils from C. bergamia, and its close relatives, C. limon, C. aurantifolia and three varieties of C. aurantium, were analyzed by GC and GC-MS. The analytical result shows that the chemical compositions of the leaf essential oils from C. bergamia are basically the same as those from three varieties of C. aurantium. Their main components are linalool (29.19-39.75% )and linalyl acetate (24.73-30.24% )etc., and contents of other components are also similar. But their peel essential oils are different. The peel essential oils from C. bergamia contain less limonene (29.94%) than those from C. aurantium (92.55-94.31% ) and less beta-pinene (3.00%) and y-terpinene(3.48% )than those from C. limon or C. aurantifolia (respectiyely 9.16% and 10.42% ) . The peel essential oils from C. bergamia contain not only as much linalool (22.20%) and linalyl acetate (32.66%)as those in the leaf essential oils from C. aurantium, but also as much limonene(29.94% )as that in the peel essential oils from C. limon or C. aurantifolia . The contents of limonene are close to those of the essential oils from C. aurantifolia. This result shows that C. bergamia may be a natural hybrid between C.aurantium and C. aurantifolia, as proposed by Sinclair W. B.     

Chemical intra-Mediterranean variation and insecticidal activity of Crithmum maritimum

The chemical composition of the volatile metabolites of Crithmum maritimum harvested from several geographic localities along the Mediterranean coasts was studied by GC and GC-MSD. The major oil constituents were found to be dillapiole, gamma-terpinene, sabinene, limonene and beta-phellandrene. The Western populations were richer in dillapiole, whereas the Southern collections were characterized by increased amounts of thymol methyl ether and gamma-terpinene. The Italian chemical profiles differentiated by the significant contributions of carvacrol methyl ether and isoterpinolene. The essential oils were also investigated for their insecticidal activity and their repellency against Pheidole pallidula (Nylander) ants and found to possess significant activity.     

Chemical Variability of Cleistopholis patens (Benth.) Engl. et Diels Leaf Oil from Ivory Coast

The chemical composition of 48 leaf oil samples isolated from individual plants of Cleistopholis patens (Benth .) Engl. et Diels harvested in four Ivoirian forests was investigated by GC‐FID (determination of retention indices), GC/MS, and ¹³C‐NMR analyses. The main components identified were β‐pinene (traces–59.1%), sabinene (traces–54.2%), (E)‐β‐caryophyllene (0.3–39.3%), linalool (0.1–38.5%), (E)‐β‐ocimene (0.1–33.2%), germacrene D (0.0–33.1%), α‐pinene (0.1–32.3%), and germacrene B (0–21.2%). The 48 oil compositions were submitted to hierarchical clustering and principal components analyses, which allowed the distinction of three groups within the oil samples. The oil composition of the major group (Group I, 33 samples) was dominated by (E)‐β‐caryophyllene and linalool. The oils of Group II (eight samples) contained mainly β‐pinene and α‐pinene, while those of Group III (seven samples) were dominated by sabinene, limonene, and β‐phellandrene. Moreover, the compositions of the Ivoirian C. patens leaf oils differed from those of Nigerian and Cameroonian origins.     

The Essential Oil of Bupleurum fruticosum L. from Corsica: A Comprehensive Study

A detailed analysis of Bupleurum fruticosum oil was carried out by combination of GC (RI), GC/MS, and ¹³C‐NMR analyses. After fractionation by column chromatography, 34 components accounting for 97.8% of the oils were identified. The main component was β‐phellandrene (67.7%), followed by sabinene (9.3%), and limonene (5.6%). The evolution of the chemical composition according to the stages of development of the plant was investigated as well as the composition of leaf, twig, and flower oils. A solvent‐free microwave extraction (SFME) of aerial parts was carried out and the composition of the extract compared with that of the essential oil. Finally, 57 oil samples isolated from aerial parts of individual plants, collected all around Corsica, were analyzed, and the data were submitted to statistical analysis. Although the contents of the main components varied, only one group emerged, accompanied with some atypical compositions.     

Inhibition of cholinesterase by essential oil from food plant

Inhibition of cholinesterase has attracted much attention recently because of its potential for the treatment of Alzheimer's disease. In this work, the anticholinesterase activities of plant oils were investigated using Ellman's colorimetric method. The results indicate that essential oils obtained from Melissa officinalis leaf and Citrus aurantifolia leaf showed high acetylcholinesterase and butyrylcholinesterase co-inhibitory activities. C. aurantifolia leaf oil revealed in this study has an IC(50) value on acetylcholinesterase and butyrylcholinesterase of 139 ± 35 and 42 ± 5 μg/ml, respectively. GC/MS analysis revealed that the major constituents of C. aurantifolia leaf oil are monoterpenoids including limonene, l-camphor, citronellol, o-cymene and 1,8-cineole.     

Essential oil composition and variability of Thymus lotocephalus and Thymusxmourae

The composition of the essential oils of four populations of Thymus lotocephalus G. López and R. Morales and one population of T.xmourae Paiva and Salgueiro, two endemic taxa from Portugal, was investigated mainly by GC and GC-MS. Txmourae is a natural hybrid between T. lotocephalus and T. mastichina (L.) L. subsp. donyanae R. Morales, which essential oil was analysed for the first time. In its oil, it was possible to find compounds of both parents, which could enable us to confirm its intermediate status between those two taxa. 1,8-Cineole and borneol were the main constituents in the essential oil of T.xmourae, whereas linalool, geranyl acetate and 1,8-cineol were the major ones in T. lotocephalus. Intermedeol was also an important constituent in the oils of both taxa. Nevertheless, the volatile oils of the four populations investigated of T. lotocephalus showed important differences among the main constituents. In order to study their infraspecific variability, the results obtained in the analysis of individual plants were submitted to a Principal Component and Chemometric Cluster Analyses. Five types of essential oils were found: linalool, 1,8-cineole, linalool/1,8-cineole, linalyl acetate/linalool and geranyl acetate.     

Essential oil of Daucus glaber Forssk

The composition of the essential oil of the fruits, leaves and stems of Daucus glaber Forssk has been studied by GC/MS. It was found that, the essential oil of the fruits consists of monoterpene hydrocarbons (limonene and sylvestrene are the majors) and phenylpropanoids (elemicin is the major). Sylvestrene has never been reported before in the essential oil of any Daucus species. The study of the essential oil of the leaves revealed the presence of monoterpene hydrocarbons; limonene and gamma-terpinene are the majors and a small amount of sylvestrene. The essential oil of stems consists of monoterpene hydrocarbons (gamma-terpinene is the major), terpene alcohols (mainly 4-terpineol) and phenylpropanoids (myristicin and elemicin are the majors). It is interesting that, the essential oil of the fruits is free from any oxygenated terpenes while that of the stems is free from limonene and sylvestrene which are present in the essential oil of the fruits and leaves in fairly large amounts The essential oil of the fruits, leaves and stems shows broad antimicrobial activities against both gram positive and gram negative bacteria. In addition, the volatile oil of the stem, particularly, show activities against Candida albicans (yeast). Also, the prepared oils have variable cytotoxic activities with LC50 21.52, 36.01 and 42.34 microg/ml, respectively.     

Evaluation of characteristic aroma compounds of Citrus natsudaidai Hayata (Natsudaidai) cold-pressed peel oil

The characteristic aroma compounds of Citrus natsudaidai Hayata essential oil were evaluated by a combination of instrumental and sensory methods. Sixty compounds were identified and quantified, accounting for 94.08% of the total peel oil constituents. Limonene was the most abundant compound (80.68%), followed by gamma-terpinene (5.30%), myrcene (2.25%) and alpha-pinene (1.30%). Nineteen compounds which could not be identified in the original oil were identified in the oxygenated fraction. Myrcene, linalool, alpha-pinene, beta-pinene, limonene, nonanal, gamma-terpinene, germacrene D, and perillyl alcohol were the active aroma components (FD-factor > 3(6)), whereas beta-copaene, cis-sabinene hydrate and 1-octanol were suggested as characteristic aroma compounds, having a Natsudaidai-like aroma in the GC effluent. Three other compounds, heptyl acetate, (E)-limonene oxide and 2,3-butanediol, which each showed a high RFA value (>35) were considered to be important in the reconstruction of the original Natsudaidai oil from pure odor chemicals. The results indicate that 1-octanol was the aroma impact compound of C. natsudaidai Hayata peel oil.     

A comparison of volatile components from the peel of Ohshima no. 1 with its parent cultivars

A total of 20 volatile organic compounds from the peel of citrus fruit Ohshima no. 1 were identified by gas chromatography-mass spectrometry (GC-MS). The amount of limonene in Ohshima no. 1 was lower than those in the parent cultivars, Miyauchi iyokan and Yoshiura ponkan, whereas those of gamma-terpinene, linalool, sabinene, p-cymene, and terpinolene in Ohshima no. 1 were somewhat higher. However, comparing the results, it was found that volatile components from both parent cultivars were present in the peel of Ohshima no. 1. Principal component analysis (PCA) of data obtained with an electronic nose indicated that the odor of Ohshima no. 1 showed a clear upward displacement as compared with those of parent cultivars in PC1. The oils of Miyauchi iyokan and Yoshiura ponkan showed displacement in a negative direction, and a positive one in PC2. By PCA analysis, it was found that the odor quality of Ohshima no. 1 was very different from those of the parent cultivars.     

Evaluation of in vitro antimicrobial activity of leaf and stem essential oils of <Emphasis Type="Italic">Chloroxylon swietenia</Emphasis> DC.

The essential oils obtained by hydrodistillation of leaves and stems of Chloroxylon swietenia DC. were analysed by GC and GC-MS. The main components in the leaf oil were limonene, pregeijerene, geijerene and germacrene D, while stem oil was rich in limonene, methyl eugenol, pregeijerene and geijerene. The essential oils were evaluated for antimicrobial activity against two gram-positive and two gram-negative bacteria and four pathogenic fungi using agar disc diffusion technique. Subsequently, the minimum inhibitory concentration (MIC) from oils was determined by broth microdilution. Both the oils exhibited moderate to strong activities against all the organisms tested. Bacillus subtilis was most susceptible at 100 μg/ml of leaf and stem oils with inhibition zones of 15.9 and 13.1 mm respectively. Among all the fungi tested, A. niger inhibited effectively with a zone of inhibition of 14.9 and 11.5 mm for leaf and stem oils respectively. The results obtained suggest that the essential oils of the plant possess antimicrobial properties and serve as a biofriendly source of antimicrobial ingredients for the food and pharmaceutical industries.     

Composition of the leaf, stem bark and root bark oils of Isolona cooperi investigated by GC (retention index), GC-MS and 13C-NMR spectroscopy

The leaf, stem bark and root bark oils of Isolona cooperi Hutchinson & Dalziel from the Ivory Coast have been analysed by GC (retention index), GC-MS and 13C-NMR spectroscopy. Two types of essential oil were produced by the plant. The leaf and stem bark oils were monoterpene-rich, containing principally (Z)-beta-ocimene and gamma-terpinene and three lactones, 5-[(E and Z)-hexylidene]-5H-furan-2-ones and massoia lactone, were present in appreciable amounts. Conversely, the root bark oil was dominated by 5-isopentenylindole and (E)-beta-caryophyllene. The strategy for the analysis of each oil was adapted according to the nature of the components.     

Chemical Composition Variability of Essential Oils of Daucus gracilis Steinh. from Algeria

The chemical compositions of 20 Algerian Daucus gracilis essential oils were investigated using GC‐FID, GC/MS, and NMR analyses. Altogether, 47 compounds were identified, accounting for 90 – 99% of the total oil compositions. The main components were linalool ( 18 ; 12.5 – 22.6%), 2‐methylbutyl 2‐methylbutyrate ( 20 ; 9.2 – 20.2%), 2‐methylbutyl isobutyrate ( 10 ; 4.2 – 12.2%), ammimajane ( 47 ; 2.6 – 37.1%), (E)‐β‐ocimene ( 15 ; 0.2 – 12.8%) and 3‐methylbutyl isovalerate ( 19 ; 3.3 – 9.6%). The chemical composition of the essential oils obtained from separate organs was also studied. GC and GC/MS analysis of D. gracilis leaves and flowers allowed identifying 47 compounds, amounting to 92.3% and 94.1% of total oil composition, respectively. GC and GC/MS analysis of D. gracilis leaf and flower oils allowed identifying linalool (22.7%), 2‐methylbutyl 2‐methylbutyrate (18.9%), 2‐methylbutyl isovalerate (13.6%), ammimajane (10.4%), 3‐methylbutyl isovalerate (10.3%), (E)‐β‐ocimene (8.4%) and isopentyl 2‐methylbutyrate (8.1%) as main components. The chemical variability of the Algerian oil samples was studied using statistical analysis, which allowed the discrimination of three main Groups. A direct correlation between the altitudes, nature of soils and the chemical compositions of the D. gracilis essential oils was evidenced.     

Studies on Leaf Oils of Citrus Species

Leaf oils from 6 domestic citrus species were analysed by gas chromatography and 32 compounds were identified as constituents of one or more oils. Most components present were common to all 6 citrus leaf oils, but the percent composition of some components, i.e. β-pinene, limonene, β-phellandrene, γ-terpinene, p-cymene, p-α-dimethylstyrene, citronellal, linalool and thymol methyl ether, differed considerably from species to species. For example, γ-terpinene is a main component (36.5%) of Shiikuwasha (Citrus depressa Hayata), but is a trace in leaf oils from Kawabata-mikan (C. aurea Tanaka) and Otaheite-orange (C. limonia Osbeck var. otaitensis Tanaka). Yuzu (C. Junos Sieb. ex Tanaka) is characterized by relatively high contents of β-phellandrene (11.2%) and p-α-dimethylstyrene (6.7%), which are minor constituents in the other 5 citrus leaf oils. Otaheite-orange is characterized by high contents of limonene (39.7%) and citronellal (10.0%).     

Purification and characterization of the monoterpene cyclase gamma-terpinene synthase from Thymus vulgaris

The monoterpene cyclase, gamma-terpinene synthase, from Thymus vulgaris (thyme) leaves was purified to apparent homogeneity by isoelectric focusing and dye-ligand, anion-exchange, hydrophobic interaction, and gel permeation chromatography. The enzyme has a native molecular weight of 96,000 as determined by gel permeation chromatography, and exhibited a specific activity of 538 nmol/h.mg protein (turnover number of approximately 0.01/s). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed the enzyme to be composed of two apparently identical subunits of Mr approximately 55,000. The protein was very hydrophobic, and possessed a pI value of 4.85 as determined by isoelectric focusing. Maximum activity was observed at pH 6.8 in the presence of 20 mM Mg2+; 5 mM Mn2+ could support catalysis, albeit at a much lower rate. The Km value for the substrate, geranyl pyrophosphate, was 2.6 microM. Cyclase activity was inhibited by cysteine- and histidine-directed reagents. Purified gamma-terpinene synthase also possessed the ability to cyclize geranyl pyrophosphate to small amounts of alpha-thujene and to lesser quantities of myrcene, alpha-terpinene, limonene, linalool, terpinen-4-ol, and alpha-terpineol, all of which appear to be coproducts of the reaction sequence leading to gamma-terpinene. In general properties, the gamma-terpinene synthase from thyme leaves resembles other monoterpene cyclases as well as sesquiterpene and diterpene cyclases.     

Studies on the Leaf Oils of Citrus Species

Leaf oil samples of four different citrus species were prepared from young leaves and the detailed composition of each leaf oil was investigated using gas chromatography, thin-layer chromatography and infrared spectrometry. The following components were identified: α-pinene, α-thujene, β-pinene, limonene, γ-terpinene, p-cymene, p-α-dimethylstyrene, β-humulene, β-selinene, trans-2-hexen-l-al, cis-3-hexen-l-ol, trans-2-hexen-l-ol, linalool terpinen-4-ol and α-terpineol. In addition, camphene, sabinene, β-myrcene, α-terpinene, β-elemene, caryophyllene, neral, geranial, nerol and geraniol were tentatively identified. Most of the components were found to be contained in common in the leaf oils of four different citrus species, but the relative contents of some of the components such as limonene, γ-terpinene, p-cymene, linalool, neral and geranial were distinctly different from species to species. Thus, gas chromatographic analyses of leaf oils seemed to be useful for the identification of citrus species.     

Chemical Variability of the Needle Oil of Juniperus communis ssp. alpina from Corsica

The composition of 109 samples of essential oil isolated from the needles of Juniperus communis ssp. alpina growing wild in Corsica was investigated by GC (in combination with retention indices), GC/MS, and ¹³C‐NMR. Forty‐four compounds accounting for 86.7–96.7% of the oil were identified. The oils consisted mainly of monoterpene hydrocarbons, in particular, limonene (9.2–53.9%), β‐phellandrene (3.7–25.2%), α‐pinene (1.4–33.7%), and sabinene (0.1–33.6%). The 109 oil compositions were submitted to k‐means partitioning and principal component analysis, which allowed the distinction of two groups within the oil samples. The composition of the major group (92% of the samples) was dominated by limonene and β‐phellandrene, while the second group contained mainly sabinene beside limonene and β‐phellandrene.     

Antimicrobial activity of six constituents of essential oil from Salvia

The antimicrobial activity of three Salvia species, i.e. S. santolinifolia, S. hydrangea and S. mirzayanii, essential oils were investigated. The essential oils were obtained from the aerial parts of plants and analyzed by GC-MS. The main constituents of aforementioned species were alpha-pinene (72.4%), beta-pinene (6.6%) and limonene (5.3%); beta-caryophyllene (25.1%), 1,8-cineol (15.2%) and caryophyllene oxide (11.5%); alpha-terpinenyl acetate (22.6%), 1,8-cineol (21.2%) and linalool (8.9%), respectively. Bioassays exhibited that the property of the oil of S. myrzayanii was superior to others. The antimicrobial activity of essential oil from Salvia species may well be due to the presence of synergy between six tested compounds (linalool, 1,8-cineol, alpha-pinene, beta-pinene, beta-caryophyllene and limonene) and other constituents of the oils with various degrees of antimicrobial activity. Among these, linalool and 1,8-cineol had the highest antimicrobial activity.     

墨红鲜花香气(头香)成分分析

利用 XAD-4憎水性吸附树脂采集墨红头香,以毛细管气相色谱双柱保留指数和 GC/MS/DS 联用方法鉴定头香的化学成份。共分离鉴定或初步鉴定了45种组份,其中含量较大的有乙酸芳樟酯(14.98%),柠檬烯(12.07%),甲基苯甲醚(9.88%),香茅醇(4.82%),乙酸巳酯(3.98%),β-石竹烯(4.55%),芳樟醇(3.18%),正巳醇(3.17%)等.     

Studies on the Components of the Essential oil from Adcnosma indianum (Lour.) Merr

This paper presents the chemical constituents of the essential oil of Adenosma indianum (Lour.) Merr. by GC and GC/MS/DS. Fivty-four components which were isolated and quantified. Thirtyfive components have been identified. The main components are α-pinene, β-pinene, limonene, p-cymene, 1,4-cineol, linalool, fenchone, o-methylanisole and δ-guaiene.