Constituents of the essential oil of a new chemotype of Elsholtzia strobilifera Benth.

The composition of the essential oil from a new chemotype of Elsholtzia strobilifera Benth. collected from sub-alpine region of central Himalaya, India, has been investigated by Gas Chromatography and Gas Chromatography–Mass Spectrometry. The GC of the oil revealed the presence of more than 50 constituents, of which neral (18.3%) and geranial (29.9%) were found to be the major compounds and an absence of monoterpene hydrocarbons. Acylfuran derivatives, the specific chemical markers of the essential oils from the genus Elsholtzia were not detected.     

Salvia verbenaca L. essential oil: Variation of yield and composition according to collection site and phenophase

The effect of the collection sites and phenophase on yield and chemical composition of Salvia verbenaca essential oils was evaluated. The essential oil constituents were assessed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The highest essential oil yields were observed for samples of the higher semi-arid bioclimate and at the flowering period. Eighty-five volatile constituents were identified and their percentages varied significantly (p < 0.05) depending on the collection site and the phenological stage. According to the plants origin, essential oils were dominated by monoterpene hydrocarbons, oxygenated monoterpenes and sesquiterpene hydrocarbons. The monoterpene hydrocarbons (31.9%) predominate at the flowering stage whereas oxygenated sesquiterpenes (27.5%) at the early fruiting stage. The sesquiterpene hydrocarbons (28.2%) was the most represented chemical class at late fruiting. On the basis of GC-MS data, the major identified volatile constituents were viridiflorol (3.4–17.7%), α-pinene (0.7–15.9%), β-caryophyllene (1.0–15.3%) and p-cymene (1.3–14.2%). S. verbenaca contains a diversity of bioactive constituents which shows large variations as affected by the collection sites and phenophase.     

Chemical Composition of Essential Oils and Aromatic Waters from Different Italian Anthemis maritima Populations

The chemical composition of the essential oils and aromatic waters isolated from six Italian Anthemis maritima populations was determined by GC‐FID and GC/MS analyses. In total, 122 and 100 chemical compounds were identified in the essential oils and the aromatic waters, respectively. The main compound classes represented in the oils were monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes, and terpene esters. Multivariate chemometric techniques such as cluster analysis (CA) and principal coordinate analysis (PCO) were used to classify the samples according to the geographical origin. Statistical analysis allowed the attribution of the analyzed populations to different chemotype groups.     

Essential‐Oil Composition and Chemical Variability of Senecio vulgaris L. from Corsica

The chemical composition of the essential oils isolated from the aerial parts of Senecio vulgaris plants collected in 30 Corsican localities was characterized using GC‐FID and GC/MS analyses. Altogether, 54 components, which accounted for 95.2% of the total oil composition, were identified in the 30 essential‐oil samples. The main compounds were α‐humulene ( 1 ; 57.3%), (E)‐β‐caryophyllene ( 2 ; 5.6%), terpinolene ( 3 ; 5.3%), ar‐curcumene ( 4 ; 4.3%), and geranyl linalool ( 5 ; 3.4%). The chemical composition of the essential oils obtained from separate organs and during the complete vegetative cycle of the plants were also studied, to gain more knowledge about the plant ecology. The production of monoterpene hydrocarbons, especially terpinolene, seems to be implicated in the plant‐flowering process and, indirectly, in the dispersal of this weed species. Comparison of the present results with the literature highlighted the originality of the Corsican S. vulgaris essential oils and indicated that α‐humulene might be used as taxonomical marker for the future classification of the Senecio genus. A study of the chemical variability of the 30 S. vulgaris essential oils using statistical analysis allowed the discrimination of two main clusters according to the soil nature of the sample locations. These results confirmed that there is a relation between the soil nature, the chemical composition of the essential oils, and morphological plant characteristics. Moreover, they are of interest for commercial producers of essential oil in selecting the most appropriate plants.     

Chemical Composition and Antimicrobial Activities of Essential Oils of Laggera pterodonta Collected in Four Different Locations in Yunnan,China*

Essential oils obtained by hydrodistillation from leaves of Laggera pterodonta collected from four different locations (Kunming, Lijiang, Puer and Xinping) in Yunnan, China, were analyzed using GC MS and GC FID. The number of compounds identified in each sample was 39, 37, 33 and 44, respectively, representing 9332% (Kunming), 8057% (Lijiang), 9224% (Puer) and 9385% (Xinping) of total essential oils. Chemical compositions of essential oils differed between sample locations: thus, those from Kunming were rich in benzenoid compounds (3806%) while those from Lijiang and Puer were largely dominated by sesquiterpenes (1989% and 4465% respectively) and sesquiterpenes oxide (4085% and 3511%, respectively), and those from Xinping contained a high proportion of monoterpene hydrocarbons and sesquiterpene hydrocarbons (4223% and 3325% respectively) (7548%). The results of tests on the antimicrobial activities of essential oils indicated that chemical composition was affected by environmental variation causing differences in sensitivity to microbes among samples.     

云南不同产地臭灵丹精油化学成分及抗菌活性

采用水蒸气蒸馏的方法,对采自云南4个不同地区（昆明,丽江,普洱,新平）的臭灵丹叶子进行挥发油提取,并利用GC MS和GC FID气相色谱联用技术分析其化学组成,分别从中鉴定出39、37、33、44个化合物。鉴定的化合物各占挥发油总量的9332% (昆明)、8057% (丽江)、9224% (普洱)和9385% (新平)。研究结果表明,采自这四个地区植物样品提取所得挥发油化学组成不尽相同：昆明产臭灵丹挥发油富含芳香族化合物(3806%);而从丽江和普洱样品中获得的挥发油化学成分以倍半萜（分别为1989%和4465%）和氧化倍半萜（分别为4085%和3511%）为主;非氧化单萜和非氧化倍半萜化合物（分别为4223%和3325%）则是新平产臭灵丹挥发油的主要化合物类型。同时,对这些不同产地的臭灵丹挥发油也进行了抗菌活性测试。从以上实验研究结果推测环境差异是影响臭灵丹挥发油化学组成差异的重要因素,而不同的化学组成可能是导致4种样品抗菌敏感程度不同的原因。     

Essential oils in the ranunculaceae family: chemical composition of hydrodistilled oils from Consolida regalis, Delphinium elatum, Nigella hispanica, and N. nigellastrum seeds

In this study, we analyzed the chemical composition of volatile oils hydrodistilled from seeds of Consolida regalis, Delphinium elatum, Nigella hispanica, and N. nigellastrum using GC and GC/MS. In C. regalis, octadecenoic (77.79%) and hexadecanoic acid (8.34%) were the main constituents. Similarly, the oils from D. elatum and N. hispanica seeds consisted chiefly of octadecadienoic (42.83 and 35.58%, resp.), hexadecanoic (23.87 and 28.59%, resp.), and octadecenoic acid (21.67 and 19.76%, resp.). Contrastingly, the monoterpene hydrocarbons α-pinene (34.67%) and β-pinene (36.42%) were the main components of N. nigellastrum essential oil. Our results confirm the presence of essential oils in the family Ranunculaceae and suggest chemotaxonomical relationships within the representatives of the genera Consolida, Delphinium, and Nigella. In addition, the presence of various bioactive constituents such as linoleic acid, (-)-β-pinene, squalene, or carotol in seeds of D. elatum, N. hispanica, and N. nigellastrum indicates a possible industrial use of these plants.     

Essential‐Oil Composition of Helichrysum italicum (Roth) G.Don ssp. italicum from Elba Island (Tuscany,Italy)

The composition of 21 essential‐oil samples isolated from Helichrysum italicum collected in seven locations of Elba Island (Tuscany, Italy), characterized by different soil types, during three different periods (January, May, and October 2010) was determined by GC‐FID and GC/EI‐MS analyses. In total, 115 components were identified, representing 96.8–99.8% of the oil composition. The oils were characterized by a high content of oxygenated monoterpenes (38.6–62.7%), while monoterpene and sesquiterpene hydrocarbons accounted for 2.3–41.9 and 5.1–20.1% of the identified constituents, respectively. The main oxygenated derivatives were nerol (2.8–12.8%) and its ester derivative neryl acetate (5.6–45.9%). To compare the chemical variability of the species within Elba Island and between the island and other localities within the Mediterranean area, studied previously, multivariate statistical analysis was performed. The results obtained showed a difference in the composition of the essential oils of H. italicum from Elba Island, mainly due to the environment where the plant grows, and, in particular, to the soil type. These hypotheses were further confirmed by the comparison of these oils with essential oils obtained from H. italicum collected on other islands of the Tuscan archipelago.     

Essential oils from two endemic species of Apiaceae from Iran

The composition of essential oils of Leutea glaucopruinosa (Rech.f.) Akhani & Salimian comb. nov., and Zeravschania (Boiss. & Hausskn.) Salimian & Akhani comb. nov. were analysed by GC-MS. 49 compounds are identified in the former and 33 compounds in the latter, comprising a total of 76 compounds in both species. Both species were originally described under Peucedanum, which are transferred in this paper into Leutea and Zeravschania, respectively. The chemical compounds of the essential oils show that there are only seven common compounds between two species. The major compounds of L. glaucopruinosa are mostly monoterpene hydrocarbons and oxygenated monoterpenes, in which alpha-pinene (31.5%), sabinene (9.7%), beta-pinene (9.2%), exo-fenchyl acetate (4.5%) are dominant. In Z. pastinacifolia sesquiterpene hydrocarbons and phenylpropanoids dominate with beta-bisabolene (37.3%), 3,1-butyl-1,2-dimethoxy benzene (14.9%), 10,11-dimethylbicyclo[6.3.0]undec-(8)-en-9-one (12.9%), 4-t-butyl-1,2-dimethoxy benzene (6.8%), (E)-asarone (5.1%) and elemicine (4.1%) as major compounds.     

Larvicidal and Nematicidal Activities of the Leaf Essential Oil of Croton regelianus

The chemical composition of the leaf essential oil of Croton regelianus collected from wild plants growing in two different sites at Ceará State (Brazil) was analyzed by GC/MS and GC‐FID. Twenty monoterpenoids, representing more than 96% of the chemical composition of the oils, were identified and quantified. The oils showed similar chemical composition but considerable variation in the levels of each constituent. Ascaridole (33.9–17.0%), p‐cymene (22.3–21.6%), and camphor (13.0–3.1%) were the predominant constituents. The monoterpene ascaridole was isolated and characterized by spectroscopic data. The essential oils and the isolated compounds were tested against Aedes aegypti and Artemia sp. larvae, and the root knot nematode Meloidogyne incognita. The bioassay results show that the essential oil of C. regelianus and ascaridole were moderately active against the M. incognita, but strongly effective against both A. aegypti and Artemia sp. larvae.     

Variability in essential oil composition of Piper dilatatum L.C. Rich

Twelve samples of air-dried aerial parts of Piper dilatatum L. C. Rich yielded essential oils and their volatile constituents were analyzed by GC and GC–MS. Sesquiterpenes, both hydrocarbons and oxygenated, were the most highly represented classes, the former ranging from 31.5% to 87.7% and the latter varying from 1.8% to 49.4%. Using hierarchical cluster analysis, the oils were divided into seven groups, whose main constituents were: (E)-caryophyllene, α-cadinol and germacrene D (group A); spathulenol, bicyclogermacrene and (Z)-β-ocimene, (group B); spathulenol, germacrene D and (E)-nerolidol, (group C); germacrene D, limonene, α-phellandrene and bicyclogermacrene (group D); β-elemene, germacrene D and β-pinene (group E); curzerene, p-cymene and α-eudesmol (group F); and (Z)-α-bisabolene, curzerene and germacrene D (group G). We have seen that Piper oils from the Amazon present as major constituents terpenoids and phenylpropanoids, always with the predominance of one over another. The essential oils of P. dilatatum presented in this paper, containing only mono- and sesquiterpenes as its major components, is further chemotaxonomic evidence of this dichotomy in the Piper genus.     

Chemotaxonomic Analysis of the Aroma Compounds in Essential Oils of Two Different Ocimum basilicum L. Varieties from Iran

Hydrodistilled essential oils of 21 accessions of Ocimum basilicum L. belonging to two different varieties (var. purpurascens and var. dianatnejadii) from Iran were characterized by GC‐FID and GC/MS analyses. The oil yield was found to be between 0.6 and 1.1% (v/w). In total, 49 compounds, accounting for 96.6–99.7% of the oil compositions, were identified. Aromatic compounds, represented mainly by methyl chavicol (33.6–49.1%), and oxygenated monoterpenes, represented by linalool (14.4–39.3%), were the main components in all essential oils. Monoterpene hydrocarbons were present in the essential oils of all accessions of the purpurascens variety, whereas they were completely absent in those of the dianatnejadii variety, indicating that monoterpene hydrocarbons might be considered as marker constituents of the purpurascens variety. The chemotaxonomic value of the essential‐oil compositions was discussed according to the results of the cluster analysis (CA). The CA showed a clear separation of the O. basilicum var. purpurascens accessions and the O. basilicum var. dianatnejadii accessions, although the data showed no major chemotype variation between the studied varieties. Indeed, the CA revealed only one principal chemotype (methyl chavicol/linalool) for both varieties. In conclusion, GC/MS analyses in combination with CA showed to be a flexible and reliable method for the characterization of the chemical profiles of different varieties of Ocimum basilicum L.     

A comparative study of Scalesia species (Asteraceae) by gas chromatographic analysis of the monoterpene hydrocarbons of their essential oils

ADSERSEN, A. & SVENDSEN, A. B., 1986. A comparative study of Scalesia species (Asteraceae) by gas chromatographic analysis of the monoterpene hydrocarbons of their essential oils. The monoterpene hydrocarbons of the essential oils of 13 species of Scalesia , Asteraceae, endemic to the Galapagos Islands, were analysed by gas chromatography to determine whether the composition of these compounds could show any characteristics for the various species. Marked differences in the monoterpene hydrocarbon patterns of the Scalesia species investigated were observed. Whereas a-pinene was usually found in amounts of 30–50%, Scalesia villosa contained only 12%. Sabinene usually occurred in amounts of 10-1.5%, but S. divisa and S. affinis contained about twice as much. The limonene content was usually less than 1%, but S. microcephala, S. baurii and S. affinis contained amounts varying from about 2% to 9.5%.     

In-vitro antimicrobial activity and chemical composition of Sardinian Thymus essential oils

Essential oils and their components are becoming increasingly popular as naturally occurring antimicrobial agents. In this work the chemical composition and the antimicrobial properties of Thymus essential oils and of their main components were determined. Three essential oils obtained from different species of Thymus growing wild in Sardinia and a commercial sample of Thymus capitatus oil were analysed. The essential oil components were identified by GC/MS analysis. The antimicrobial activity of the oils and components was determined against a panel of standard reference strains and multiple strains of food-derived spoilage and pathogenic bacteria, using a broth microdilution method. The GC/MS analysis showed that the major constituents of the oils were monoterpene hydrocarbons and phenolic monoterpenes, but the concentration of these compounds varied greatly among the oils examined. The results of the antimicrobial assay showed that essential oils extracted from Sardinian Thymus species have an antimicrobial activity comparable to the one observed in other thyme oils. It seems also confirmed that the antimicrobial properties of thyme essential oils are mainly related to their high phenolic content. Among the single compounds tested carvacrol and thymol turned out to be the most efficient against both reference strains and food-derived bacteria. The results of this study confirmed the possibility of using thyme essential oils or some of their components in food systems to prevent the growth of foodborne bacteria and extend the shelf-life of processed foods.     

Chemical composition and intraspecific variability of the essential oils of five populations of Hypericum triquetrifolium Turra growing in North Tunisia

The chemical composition of the essential oils of five populations of Hypericum triquetrifolium Turra from Tunisia and their intraspecific variability were analyzed in detail by GC/MS. One hundred seventy-four compounds were identified, representing averages of 87.9 to 98.7% of the oil composition. The components are represented here by homologous series of monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpenes hydrocarbons, oxygenated sesquiterpenes, non-terpenic hydrocarbons, and others. Sesquiterpene hydrocarbons were the most abundant chemical compounds. Multivariate chemometric techniques, such as cluster analysis (CA) and principal-component analysis (PCA), were used to characterize the samples according to the geographical origin. By statistical analysis, the analyzed populations were classified into four chemotype groups.     

Phylogenetic relationships of the genus Chamaecyparis inferred from leaf essential oil

The species differentiation between Chamaecyparis formosensis, C. obtusa var. formosana, and C. obtusa, based on the composition of the leaf essential oils, was studied. The characterization of the oils by GC-FID and GC/MS analyses showed remarkable differences between these three essential oils. Cluster analysis (CA) and principal-component analysis (PCA) distinguished three groups of essential oils. The C. formosensis oil was dominated by α-pinene while those isolated from C. obtusa var. formosana and C. obtusa were characterized by high levels of (-)-thujopsene and α-terpinyl acetate, respectively. Moreover, the phylogenetic relationships of the genus Chamaecyparis were in agreement with previous findings based on morphological and molecular evidence. In addition, the essential oils from C. obtusa var. formosana could be classified into three chemical types, according to their different characteristic main compounds (β-elemol, (-)-thujopsene, and cis-thujopsenal). The biochemical correlations between the major constituents of the Chamaecyparis species were examined and their relationship is discussed.     

Chemical variability of the wood essential oil of Cedrus atlantica Manetti from Corsica

The composition of 48 samples of essential oil isolated from the wood of Cedrus atlantica growing in Corsica was investigated by GC (in combination with retention indices), GC/MS, and (13) C-NMR. Twenty-three compounds accounting for 73.9-96.0% of the oil composition were identified. The oils consisted mainly of monoterpene hydrocarbons and sesquiterpenes, in particular α-pinene (5; up to 79.4%), himachalol (4; up to 66.2%), β-pinene (up to 21.4%), β-himachalene (2; up to 19.3%), γ-himachalene (3; up to 11.0%), and α-himachalene (1; up to 10.9%). The 48 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 Group I (44% of the samples) was dominated by 5, while the samples of Group II (56% of the samples) contained mainly 4.     

Variability in Foliar Essential Oils among Different Morphotypes of Lantana Species Complexes,and Its Taxonomic and Ecological Significance

The genus Lantana has many species complexes, and L. camara is one of the aggressive alien weedy species complexes; species delimitation in these complexes is a nightmare for taxonomists. We examined the diversity in the chemical composition of foliar essential oils among morphotypes of Lantana species complexes inhabiting the same ecological gradient, and its taxonomic and ecological significance. The yields of essential oils varied from 0.1 to 0.79% in foliar hydrodistillates of eleven morphotypes, and a total of 39 chemical constituents were detected by GC/MS. The quantitative and qualitative variability in the composition of essential oils among morphotypes was very high, and hence they represent chemotypes. The diversity observed in the composition of essential oils appears to be of genetic origin and thus of taxonomic value. The formation of distinct clusters and sub‐clusters at high distance cluster combine values also substantiates that the patterns of distribution of chemical constituents among morphotypes can be used in delimiting species and infraspecific taxa within the species complexes. The presence of β‐caryophyllene and other such compounds, which are known to prevent herbivory, in morphotypes of Lantana species complexes suggest that these compounds may provide selective advantage to Lantana over native species in the invasion of new and disturbed habitats.     

Volatiles of Geranium purpureum Vill. and Geranium phaeum L.: Chemotaxonomy of Balkan Geranium and Erodium Species (Geraniaceae)

The essential oils obtained by hydrodistillation of Geranium purpureum and G. phaeum were characterized by GC‐FID and GC/MS analyses (the former for the first time in general). In total, 154 constituents were identified, accounting for 89.0–95.8% of the detected GC peak areas. The investigated essential oils consisted mainly of fatty acids and fatty‐acid‐derived compounds (45.4–81.3%), with hexadecanoic acid and (E)‐phytol as the major components. The chemotaxonomic significance of the variations in the essential‐oil composition/production of the presently and previously investigated Geranium and highly related Erodium taxa from Serbia and Macedonia was assessed by multivariate statistical analyses. The main conclusions drawn from the high chemical similarity of the two genera, visible from the obtained dendrograms and biplots, confirm the close phylogenetic relationship between the investigated Geranium and Erodium taxa, i.e., that there is no great intergeneric oil‐composition variability. Changes in the composition and production of essential oils of the herein investigated taxa and 60 other randomly chosen species belonging to different plant genera were also statistically analyzed. The results put forward pro arguments for the oil‐yield–oil‐composition correlation hypothesis.     

Chemical Composition and Biological Activities of Tunisian Cupressus arizonica Greene Essential Oils

The chemical composition of the essential oils obtained by hydrodistillation of leaves, stems, and female cones of Cupressus arizonica Greene , grown in Tunisia, was studied by GC‐FID and GC/MS analyses. Altogether, 62 compounds were identified, 62 in the leaf oil, 19 in the cone oil, and 24 in the stem oil. The cone and stem oils were mainly composed by monoterpene hydrocarbons (96.6 and 85.2%, resp.). In the leaf oil, the total sesquiterpene fraction constituted 36.1% and that of the monoterpene hydrocarbons 33.8% of the total oil composition. The three oils were evaluated for their in vitro herbicidal activity by determining their influence on the germination and the shoot and root growth of the four weed species Sinapis arvensis L., Lolium rigidum Gaudin , Trifolium campestre Schreb ., and Phalaris canariensis L. At the highest doses tested (0.8 and 1.0 mg/ml), the leaf essential oil inhibited either totally or almost completely the seed germination and the shoot and root growth of S. arvensis and T. campestre. The oils were also tested for their antifungal activity; however, their effects on the fungal growth were statistically not significant.