Chemical Composition of Juniperus communis L. Cone Essential Oil and Its Variability among Wild Populations in Kosovo

Ripe cones of Juniperus communis L. (Cupressaceae) were collected from five wild populations in Kosovo, with the aim of investigating the chemical composition and natural variation of essential oils between and within wild populations. Ripe cones were collected, air dried, crushed, and the essential oils obtained by hydrodistillation. The essential‐oil constituents were identified by GC‐FID and GC/MS analyses. The yield of essential oil differed depending on the population origins and ranged from 0.4 to 3.8% (v/w, based on the dry weight). In total, 42 compounds were identified in the essential oils of all populations. The principal components of the cone‐essential oils were α‐pinene, followed by β‐myrcene, sabinene, and D ‐limonene. Taking into consideration the yield and chemical composition, the essential oil originating from various collection sites in Kosovo fulfilled the minimum requirements for J. communis essential oils of the European Pharmacopoeia. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were used to determine the influence of the geographical variations on the essential‐oil composition. These statistical analyses suggested that the clustering of populations was not related to their geographic location, but rather appeared to be linked to local selective forces acting on the chemotype diversity.     

Chemodiversity of Volatile Oils in Thapsia garganica L. (Apiaceae)

The chemical composition of the volatile oils obtained from the roots, leaves, flowers, and stems of Thapsia garganica of Tunisian origin was investigated by GC‐FID and GC/MS analyses. Sesquiterpene hydrocarbons and oxygenated monoterpenes were predominant in the oils of all plant parts. Bicyclogermacrene (21.59–35.09%) was the main component in the former compound class, whereas geranial (3.31–14.84%) and linalool (0.81–10.9%) were the most prominent ones in the latter compound class. Principal‐component (PCA) and hierarchical‐cluster (HCA) analyses revealed some common constituents, but also significant variability amongst the oils of the different plant parts. This organ‐specific oil composition was discussed in relation to their biological and ecological functions. For the evaluation of the intraspecific chemical variability in T. garganica, the composition of the flower volatile oils from four wild populations was investigated. Bicyclogermacrene, linalool, and geranial were predominant in the oils of three populations, whereas epicubenol, β‐sesquiphellandrene, and cadina‐1,4‐diene were the most prominent components of the oil of one population. PCA and HCA allowed the separation of the flower oils into three distinct groups, however, no relationship was found between the volatile‐oil composition and the geographical distribution and pedoclimatic conditions of the studied populations.     

Extraction Yield,Chemical Composition,Preliminary Toxicity of Bignonia nocturna (Bignoniaceae) Essential Oil and in Silico Evaluation of the Interaction

Bignonia nocturna (Bignoniaceae) is a plant used for medicinal purposes by the Amazonian indigenous peoples. To date, there have been no reported studies on its toxicity. The present study aimed to evaluate the chemical composition of essential oils obtained from Bignonia nocturna by different extraction techniques. In addition, an in silico study of the molecular interactions was performed using molecular docking and molecular dynamics. The extractions were carried out by hydrodistillation, simultaneous distillation-extraction, and steam distillation, using samples collected from the Amazon in summer and winter. The chemical composition was analyzed by GC/FID and GC/MS, and the cytotoxic activity in Artemia salina Leach was evaluated. The maximum yield (1.38 % w/w) was obtained by hydrodistillation. The results indicated that benzaldehyde predominated in all the fractions of both the volatile concentrate and the essential oils. In addition, the oil proved to be highly toxic to Artemia salina. The computer simulation results indicated that benzaldehyde strongly interacts with acetylcholinesterase, which is the likely interaction mechanism responsible for the cytotoxicity.     

Comparative Chemical Composition of the Essential Oils Obtained by Microwave‐Assisted Hydrodistillation and Hydrodistillation from Agrimonia pilosa Ledeb. Collected in Three Different Regions of China

Conventional hydrodistillation (HD) and microwave‐assisted hydrodistillation (MAHD) were performed to obtain the volatile oils of Agrimonia pilosa Ledeb . harvested in three different regions of China, which were subsequently characterized by GC‐FID and GC/MS analyses. Compared with HD, MAHD was advantageous in terms of energy savings and extraction time (60 vs. 240 min for MAHD and HD, resp.). The chemical composition varied among the different oils obtained, and the variations in the contents of the main constituents of the oils were irregular. Hence, these variations affected both the quantity and composition of the oils. The oil yields (0.15–0.21%) were affected by the method of extraction and the region of harvest, with the maximum amount of oil obtained by MAHD for the plants collected in Hubei (HB) and the minimum yield obtained by HD for the plants from Zhejing (ZJ). Hexadecanoic acid constituted the major compound of the essential oils, with the highest content found in the oil obtained by HD for plants from HB (41.18%) and the lowest one found in the oil obtained by MAHD from plants from ZJ (11.83%). Microwave irradiation did not adversely affect the composition of the essential oils. The findings show that MAHD is a modern, green, and fast technology.     

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.     

Phytochemical Diversity of the Essential Oils of Mexican Oregano (Lippia graveolens Kunth) Populations along an Edapho‐Climatic Gradient

Mexican oregano (Lippia graveolens) is an important aromatic plant, mainly used as flavoring and usually harvested from non‐cultivated populations. Mexican oregano essential oil showed important variation in the essential‐oil yield and composition. The composition of the essential oils extracted by hydrodistillation from 14 wild populations of L. graveolens growing along an edaphoclimatic gradient was evaluated. Characterization of the oils by GC‐FID and GC/MS analyses allowed the identification of 70 components, which accounted for 89–99% of the total oil composition. Principal component and hierarchical cluster analyses divided the essential oils into three distinct groups with contrasting oil compositions, viz., two phenolic chemotypes, with either carvacrol (C) or thymol (T) as dominant compounds (contents >75% of the total oil composition), and a non‐phenolic chemotype (S) dominated by oxygenated sesquiterpenes. While Chemotype C was associated with semi‐arid climate and shallower and rockier soils, Chemotype T was found for plants growing under less arid conditions and in deeper soils. The plants showing Chemotype S were more abundant in subhumid climate. High‐oil‐yield individuals (>3%) were identified, which additionally presented high percentages of either carvacrol or thymol; these individuals are of interest, as they could be used as parental material for scientific and commercial breeding programs.     

槲寄生挥发性成分研究

目的：研究槲寄生挥发性成分。方法：利用水蒸汽蒸馏法提取槲寄生挥发性成分,用GC/MS进行分离测定,结合计算机检索技术对分离的化合物进行结构鉴定,应用色谱峰面积归一化法计算各成分的相对百分含量。结果：分离出119个成分,确定了66个化合物,占挥发油总量的77．31％。结论：槲寄生挥发性成分大于2％的化学成分有12种。     

Variation of the Chemical Composition and Antimicrobial Activity of the Essential Oils of Natural Populations of Tunisian Daucus carota L. (Apiaceae)

The essential oils of Daucus carota L. (Apiaceae) seeds sampled from ten wild populations spread over northern Tunisia were characterized by GC‐FID and GC/MS analyses. In total, 36 compounds were identified in the D. carota seed essential oils, with a predominance of sesquiterpene hydrocarbons in most samples (22.63–89.93% of the total oil composition). The main volatile compounds identified were β‐bisabolene (mean content of 39.33%), sabinene (8.53%), geranyl acetate (7.12%), and elemicin (6.26%). The volatile composition varied significantly across the populations, even for oils of populations harvested in similar areas. The chemometric principal component analysis and the hierarchical clustering identified four groups, each corresponding to a composition‐specific chemotype. The in vitro antimicrobial activity of the isolated essential oils was preliminarily evaluated, using the disk‐diffusion method, against one Gram‐positive (Staphylococcus aureus) and two Gram‐negative bacteria (Escherichia coli and Salmonella typhimurium), as well as against a pathogenic yeast (Candida albicans). All tested essential oils exhibited interesting antibacterial and antifungal activities against the assayed microorganisms.     

Contribution of microwave accelerated distillation in the extraction of the essential oil of Zygophyllum album L.

Introduction – The aerial parts of Zygophyllum album L. are used in folk medicine as an antidiabetic agent and as a drug active against several pathologies. In this work we present the chemical composition of Algerian essential oils obtained by microwave accelerated distillation (MAD) extraction, a solventless method assisted by microwave. Objective – Under the same analytical conditions and using GC‐FID and GC‐MS, the chemical composition of the essential oil of Zygophyllum album L. extracted by MAD was compared with that achieved using hydrodistillation (HD). Methodology – The extracted compounds were hydrosoluble, and they were removed from the aqueous solution by a liquid extraction with an organic solvent. Results – Employing MAD (100°C, 30 min), the essential oil contained mainly oxygenated monoterpenes with major constituents: carvone and α‐terpineol. However, most of the compounds present in the hydrodistilled volatile fraction were not terpene species, with β‐damascenone as a major constituent. Conclusion – The MAD method appears to be more efficient than HD: after 30 min extraction time, the obtained yields (i.e. 0.002%) were comparable to those provided by HD after 3 h extraction. MAD seems to be more convenient since the volatile fraction is richer in oxygenated monoterpenes, species that are recognised for their olfactory value and their contribution to the fragrance of the essential oil. Copyright © 2010 John Wiley & Sons, Ltd.     

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.     

Comprehensive two‐dimensional gas chromatography–mass spectrometry analysis of volatile constituents in Thai vetiver root oils obtained by using different extraction methods

Introduction – Vetiver root oil is known as one of the finest fixatives used in perfumery. This highly complex oil contains more than 200 components, which are mainly sesquiterpene hydrocarbons and their oxygenated derivatives. Since conventional GC‐MS has limitation in terms of separation efficiency, the comprehensive two‐dimensional GC‐MS (GC × GC‐MS) was proposed in this study as an alternative technique for the analysis of vetiver oil constituents. Objective – To evaluate efficiency of the hyphenated GC × GC‐MS technique in terms of separation power and sensitivity prior to identification and quantitation of the volatile constituents in a variety of vetiver root oil samples. Methodology – Dried roots of Vetiveria zizanioides were subjected to extraction using various conditions of four different methods; simultaneous steam distillation, supercritical fluid, microwave‐assisted, and Soxhlet extraction. Volatile components in all vetiver root oil samples were separated and identified by GC‐MS and GC × GC‐MS. The relative contents of volatile constituents in each vetiver oil sample were calculated using the peak volume normalization method. Results – Different techniques of extraction had diverse effects on yield, physical and chemical properties of the vetiver root oils obtained. Overall, 64 volatile constituents were identified by GC‐MS. Among the 245 well‐resolved individual components obtained by GC × GC‐MS, the additional identification of 43 more volatiles was achieved. Conclusion – In comparison with GC‐MS, GC × GC‐MS showed greater ability to differentiate the quality of essential oils obtained from diverse extraction conditions in terms of their volatile compositions and contents. Copyright © 2009 John Wiley & Sons, Ltd.     

Composition and Antimicrobial Activity of the Essential Oils of Laserpitium latifolium L. and L. ochridanum Micevski (Apiaceae)

The chemical composition and antimicrobial activity of essential oils of Laserpitium latifolium and L. ochridanum were investigated. The essential oils were isolated by steam distillation and characterized by GC‐FID and GC/MS analyses. All essential oils were distinguished by high contents of monoterpenes, and α‐pinene was the most abundant compound in the essential oils of L. latifolium underground parts and fruits (contents of 44.4 and 44.0%, resp.). The fruit essential oil was also rich in sabinene (26.8%). Regarding the L. ochridanum essential oils, the main constituents were limonene in the fruit oil (57.7%) and sabinene in the herb oil (25.9%). The antimicrobial activity of these essential oils as well as that of L. ochridanum underground parts, whose composition was reported previously, was tested by the broth‐microdilution method against four Gram‐positive and three Gram‐negative bacteria and two Candida albicans strains. Except the L. latifolium underground‐parts essential oil, the other investigated oils showed a high antimicrobial potential against Staphylococcus aureus, S. epidermidis, Micrococcus luteus, or Candida albicans (minimal inhibitory concentrations of 13.0–73.0 μg/ml), comparable to or even higher than that of thymol, which was used as reference compound.     

(Chemotaxonomic) Implications of Postharvest/Storage‐Induced Changes in Plant Volatile Profiles – the Case of Artemisia absinthium L. Essential Oil

The plant volatile profile and the essential‐oil chemical composition change during the storage of plant material. The objective of this study was to develop a mathematical model able to predict, explain, and quantify these changes. Mathematical equations, derived under the assumption that the essential oil contained within plant material could be treated as an ideal solution (Raoult's law), were applied for tracking of postharvest changes in the volatile profile of Artemisia absinthium L. (the essential oils were analyzed by GC‐FID and GC/MS). Starting from a specific chemical composition of an essential‐oil sample obtained from plant material after a short drying period (typically 5–10 d), and by using the equations derived from this model, one could easily predict evaporation‐induced changes in the volatile profile of the plant material. Based on the composition of the essential‐oil sample obtained after a given storage time t, it is possible to identify those components that were involved in chemical reactions, both as reactants and possible products. The established model even allowed the recognition of pairs of transformation, i.e., ‘daughter’ products and their ‘parent’ compounds. The obtained results highlight that the essential‐oil composition is highly dependent on the storage period of any plant material and urges caution in different types of phytochemical studies, especially chemotaxonomic ones, or practical application.     

Chemical Diversity and Antimicrobial Activity of Volatile Compounds from Zanthoxylum zanthoxyloides Lam. according to Compound Classes,Plant Organs and Senegalese Sample Locations

The chemical diversity of Zanthoxylum zanthoxyloides growing wild in Senegal was studied according to volatile compound classes, plant organs and sample locations. The composition of fruit essential oil was investigated using an original targeted approach based on the combination of gas chromatography (GC) and liquid chromatography (LC) both coupled with mass spectrometry (MS). The volatile composition of Z. zanthoxyloides fruits exhibited relative high amounts of hydrocarbon monoterpenes (24.3 – 55.8%) and non‐terpenic oxygenated compounds (34.5 – 63.1%). The main components were (E)‐β‐ocimene (12.1 – 39%), octyl acetate (11.6 – 21.8%) and decanol (9.7 – 15.4%). The GC and GC/MS profiling of fruit essential oils showed a chemical variability according to geographical locations of plant material. The LC/MS/MS analysis of fruit oils allowed the detection of seven coumarins in trace content. The chemical composition of fruit essential oils was compared with volatile fractions of leaves and barks (root and trunk) from the same plant station. Hexadecanoic acid, germacrene D and decanal were identified as the major constituents of leaves whereas the barks (root and trunk) were dominated by pellitorine (85.8% and 57%, respectively), an atypic linear compound with amide group. The fruit essential oil exhibited interesting antimicrobial activities against Staphylococcus aureus and Candida albicans, particularly the alcohol fraction of the oil.     

Biochemical Characterization of Helichrysum italicum (Roth) G.Don subsp. italicum (Asteraceae) from Montenegro: Phytochemical Screening,Chemotaxonomy, and Antioxidant Properties

The chemical composition and antioxidant properties of the essential oil and EtOH extract of immortelle (Helichrysum italicum (Roth) G.Don subsp. italicum, Asteraceae) collected in Montenegro were evaluated. The essential oil was characterized by GC/MS analysis, and the content of total phenolics and flavonoids in the EtOH extract was determined using the Folin? Ciocalteu reagent. The free‐radical‐scavenging capacity (RSC) of both the essential oil and the EtOH extract was assessed with the 2,2‐diphenyl‐1‐pycrylhydrazyl (DPPH) method. Moreover, the inhibition of hydroxyl radical (^.OH) generation by the EtOH extract of immortelle was evaluated for the first time here. Neryl acetate (28.2%) and γ‐curcumene (18.8%) were the main compounds in the essential oil, followed by neryl propionate (9.1%) and ar‐curcumene (8.3%). The chemical composition of the oils of the examined and additional 16 selected Helichrysum italicum taxa described in literature were compared using principal component (PCA) and cluster (CA) analyses. The results of the statistical analyses implied the occurrence of at least four different main and three subchemotypes of essential oils. Considering the antioxidant properties, the EtOH extract of immortelle exhibited similar potential as propyl gallate and quercetin, while the essential oil exhibited relatively weak DPPH^.‐scavenging capacity.     

Environmental and seasonal impacts on the chemical composition of Satureja horvatii Šilić (Lamiaceae) essential oils

The chemical composition of the essential oils of Satureja horvatii Šilić from two natural habitats (Mt. Orjen and Mt. Lovćen in Montenegro) and from cultivated plants (Belgrade, Serbia) were characterized. For the latter, plants from the locus classicus, i.e., Orjenske Lokve (Mt. Orjen), were transferred to Belgrade and, after three years of cultivation, the chemical composition of their essential oils at different phenological stages was analyzed. The essential oils were obtained from the aerial parts of the plants by hydrodistillation and analyzed by GC and GC/MS. The yields and chemical compositions of the S. horvatii oils showed significant differences between the plants collected in the natural habitats and those from cultivation, as well as between the plants at different phenological stages. In the populations from the natural habitats, growing in Mediterranean conditions, the most abundant oil constituents were the phenols thymol (63.7% in the samples from Mt. Orjen) or carvacrol (68.1% in the samples from Mt. Lovćen), while the oils from the cultivated plants (Belgrade), growing in continental conditions, were dominated by linalool (up to 65.8 and 55.9% in average). The basic characteristics of the essential oil from plants at the early phenological stage (before flowering) were high percentages of linalool (37.4%), thymol (27.3%), and carvacrol (12.2%). At the stage of flowering, the percentage of linalool (56.6–57.5%) increased, while those of thymol (15.5–15.8%) and carvacrol (1.4–1.5%) significantly decreased. The essential oil of plants in the full stage of fruiting was characterized by the domination of linalool (58.4 and 65.8%) and lower percentages of thymol (7.6 and 1.3%) and carvacrol (0.7 and 0.1%). In conclusion, the oil composition of S. horvatii was found to depend on the pedoclimatic conditions of the habitat and the phenological stage of the plants.     

Genetic Diversity and Chemical Polymorphism of Some Thymus Species

To ascertain whether there are chemical and genetic relationships among some Thymus species and also to determine correlation between these two sets of data, the essential‐oil composition and genetic variability of six populations of Thymus including: T. daenensis ?elak. (two populations), T. fallax Fisch . & C.A.Mey ., T. fedtschenkoi Ronniger , T. migricus Klokov & Des .‐Shost ., and T. vulgaris L. were analyzed by GC and GC/MS, and also by randomly amplified polymorphic DNA (RAPD). Thus, 27 individuals were analyzed using 16 RAPD primers, which generated 264 polymorphic scorable bands and volatiles isolated by distillation extraction were subjected to GC and GC/MS analyses. The yields of oils ranged from 2.1 to 3.8% (v/w), and 34 components were identified, amounting to a total percentage of 97.8–99.9%. RAPD Markers allowed a perfect distinction between the different species based on their distinctive genetic background. However, they did not show identical clustering with the volatile‐oil profiles.     

Enantioselective GC–MS analysis of volatile components from rosemary (Rosmarinus officinalis L.) essential oils and hydrosols

Essential oils and hydrosols were extracted from rosemary harvested in different seasons, and the chemical compositions of volatile components in the two fractions were analyzed by gas chromatography–mass spectrometry (GC–MS). Enantiomers of some volatile components were also analyzed by enantioselective GC–MS. Classification of aroma components based on chemical groups revealed that essential oils contained high levels of monoterpene hydrocarbons but hydrosols did not. Furthermore, the enantiomeric ratios within some volatile components were different from each other; for example, only the (S)-form was observed for limonene and the (R)-form was dominant for verbenone. These indicate the importance of determining the enantiomer composition of volatile components for investigating the physiological and psychological effects on humans. Overall, enantiomeric ratios were determined by volatile components, with no difference between essential oils and hydrosols or between seasons.     

Phytochemical Fingerprints of Copaiba Oils (Copaifera multijuga Hayne) Determined by Multivariate Analysis

Oils of various species of Copaifera are commonly found in pharmacies and on popular markets and are widely sold for their medicinal properties. However, the chemical variability between and within species and the lack of standardization of these oils have presented barriers to their wider commercialization. With the aim to recognize patterns for the chemical composition of copaiba oils, 22 oil samples of C. multijuga Hayne species were collected, esterified with CH₂N₂, and characterized by GC‐FID and GC/MS analyses. The chromatographic data were processed using hierarchical cluster analysis (HCA) and principal component analysis (PCA). In total, 35 components were identified in the oils, and the multivariate analyses (MVA) allowed the samples to be divided into three groups, with the sesquiterpenes β‐caryophyllene and caryophyllene oxide as the main components. These sesquiterpenes, which were detected in all the samples analyzed in different concentrations, were the most important constituents in the differentiation of the groups. There was a prevalence of sesquiterpenes in all the oils studied. In conclusion, GC‐FID and GC/MS analyses combined with MVA can be used to determine the chemical composition and to recognize chemical patterns of copaiba oils.     

Chemical Composition and Aroma Evaluation of Essential Oils from Evolvulus alsinoides L.

The aim of this study was to investigate the chemical composition and the odor‐active compounds of the essential oils from Evolvulus alsinoides, which is a well‐known edible and medicinal plant. The volatile compounds in the oils were identified by hydrodistillation (HD) and solvent‐assisted flavor evaporation (SAFE) in combination with GC, GC/MS, GC/O (=olfactometry), aroma extract dilution analysis (AEDA), and relative flavor activities (RFA values). The most abundant compound in the HD oil was cis‐α‐necrodol (12.62%), an irregular monoterpene with a cyclopentane skeleton, which is very unusual in the plant kingdom. In the SAFE oil, the main components included 2‐butoxyethanol (9.01%), benzyl alcohol (8.01%), and γ‐butyrolactone (7.37%). Through sensory analysis, 21 aroma‐active compounds were identified by GC/O. The most intense aroma‐active compounds in the HD oil were hexan‐1‐ol and γ‐nonalactone, both of which showed high RFA values. α‐Methyl‐γ‐butyrolactone and dimethyl sulfone contributed more strongly to the aroma of the SAFE oil. These results imply that the essential oils of E. alsinoides deserve further investigation in the food industry.