Environment‐Related Variations of the Composition of the Essential Oils of Rosemary (Rosmarinus officinalis L.) in the Balkan Penninsula

Composition of the essential oils of Rosmarinus officinalis of ten populations from the Balkan Peninsula were determined by GC/FID and GC/MS. The main constituents were 1,8‐cineole, camphor, α‐pinene, and borneol. Multivariate statistical analysis (UPGMA cluster analysis and principal‐component analysis (PCA)) revealed two major types of rosemary oil, i.e., 1,8‐cineole and camphor‐type, and two intermediate types, i.e., camphor/1,8‐cineole/borneol type and 1,8‐cineole/camphor type. The regression analyses (simple linear regression and stepwise multiple regression) have shown that, with respect to basic geographic, orographic, and 19 bioclimatic characteristics of each population, bioclimatic factor temperature of habitat represented the dominant abiogenetic factor, which, in chemical sense, led to differentiation of populations in the studied region. Also, the regression analysis have shown that some constituents of essential oils are independent of any single bioclimatic factors. However, some constituents display statistically significant correlations with some abiotic factors.     

Chemical Composition and Antifungal Activity of the Essential Oils of Lavandula pedunculata (Miller) Cav.

The chemical composition and antifungal activity of the essential oils of Lavandula pedunculata (Miller ) Cav. , harvested in North and Central Portugal, were investigated. The essential oils were isolated by hydrodistillation and analyzed by GC and GC/MS. The minimal‐inhibitory concentration (MIC) and the minimal‐lethal concentration (MLC) of the essential oils and of their major constituents were used to evaluate the antifungal activity against different strains of fungi involved in candidosis, dematophytosis, and aspergillosis. The oils were characterized by a high percentage of oxygenated monoterpenes, the main compounds being 1,8‐cineole (2.4–55.5%), fenchone (1.3–59.7%), and camphor (3.6–48.0%). Statistical analysis differentiated the essential oils into two main types, one characterized by the predominance of fenchone and the other one by the predominance of 1,8‐cineole. Within the 1,8‐cineole chemotype, two subgroups were well‐defined taking into account the percentages of camphor. A significant antifungal activity of the oils was found against dermatophyte strains. The essential oil with the highest content of camphor was the most active with MIC and MLC values ranging from 0.32–0.64 μl/ml.     

Variations in Essential Oil Composition and Antioxidant Activity in Perovskia abrotanoides Kar. Collected from Different Regions in Iran

Essential oil (EO) composition, phenolic content, and antioxidant activity were investigated in 17 P. abrotanoides populations collected from different geographical regions in Iran. The highest (3.61%) and lowest (1.25%) essential oil yields were measured in populations from Semnan Province (PSESM₂) and PISKS from Isfahan Province, respectively. GC/MS analysis identified camphor (4.05 – 35.94%), 1,8‐cineole (7.15 – 24.34%), borneol (0 – 21.75%), and α‐pinene (2.05 – 10.33%) as the main constituents of Perovskia essential oil. Cluster analysis classified the studied populations into four different groups: (I) high camphene, (II) high camphor/1,8‐cineole, (III) high borneol/δ‐3‐carene, and (IV) high α‐cadinol/trans‐caryophyllene. The highest flavonoid and phenolic contents were detected in PISAK from Isfahan Province (4.09 ± 0.05 mgQE/gDW, 58.51 ± 1.63 mgGAE/gDW) and PKRGS from Khorasan Province (3.80 ± 0.002 mgQE/gDW, 66.86 ± 0.002 mgGAE/gDW). DPPH and reducing power activity model systems identified PMASA and PKRKL as the populations with the highest antioxidant activity. Finally, the data obtained represented valuable information for introducing elite populations with EO components favorable to pharmaceutical and industrial applications.     

Chemical Composition and Antimicrobial Activity of Essential Oils from Scabiosa arenaria Forssk. Growing Wild in Tunisia

The essential oils isolated from three organs, i.e., fruits, stems and leaves, and flowers, of the endemic North African plant Scabiosa arenaria Forssk . were screened for their chemical composition, as well as their possible antibacterial, anticandidal, and antifungal properties. According to the GC‐FID and GC/MS analyses, 61 (99.26% of the total oil composition), 79 (98.43%), and 51 compounds (99.9%) were identified in the three oils, respectively. While α‐thujone (34.39%), camphor (17.48%), and β‐thujone (15.29%) constituted the major compounds of the fruit oil, chrysanthenone (23.43%), together with camphor (12.98%) and α‐thujone (10.7%), were the main constituents of the stem and leaf oil. In the case of the flower oil, also chrysanthenone (38.52%), camphor (11.75%), and α‐thujone (9.5%) were identified as the major compounds. Furthermore, the isolated oils were tested against 16 Gram‐positive and Gram‐negative bacteria, four Candida species, and nine phytopathogenic fungal strains. It was found that the oils exhibited interesting antibacterial and anticandidal activities, comparable to those of thymol, which was used as positive control, but no activity against the phytopathogenic fungal strains was observed.     

Essential Oil Compositions and Antibacterial and Antioxidant Activities of Five Lavandula stoechas Cultivars Grown in Thailand

The essential oils of five Lavandula stoechas cultivars grown in Thailand were characterized for their volatile compounds using GC‐FID and GC/MS methods as well as screened for antibacterial and antioxidant activities. Dried aerial parts, including flowers and stems from each cultivar, were subjected to hydrodistillation for 4 h. The essential oil yields were 0.18 %–0.82 % w/w. Of the 95 compounds detected and identified, 1,8‐cineole, fenchone, and camphor were considered the major compounds. Essential oil from each cultivar demonstrated different patterns of antibacterial activity and a variety of antioxidant properties. The highest antibacterial activity, MIC=0.39 mg mL^?1, was observed from the essential oil of L. stoechas ‘major’ (against Klebsiella pneumoniae and Salmonella typhimurium) and the essential oil of L. stoechas ‘white lavender’ (against S. typhimurium). The essential oil of L. stoechas×viridis ‘St. Brelade’ possessed the highest antioxidant capacity, as determined by the DPPH and ABTS assays (IC₅₀ of 67.65 and 89.26 mg mL^?1, respectively). The results indicated that some of these essential oils could be used as key ingredients in lavender oil products in Thailand to increase their therapeutic efficacy, depending on their intended application.     

Chemical Composition of the Leaf and Flower Essential Oils of Tunisian Lavandula dentata L. (Lamiaceae)

Essential oils of Lavandula dentata, a Tunisian native plant, were isolated from leaves and flowers by hydrodistillation in a Clevenger‐type apparatus and characterized by GC‐FID and GC/MS analyses. The average essential oil yields, means of five replicates, were higher for the flowers (8.60 mg/g) than for the leaves (6.56 mg/g). A total of 72 compounds were identified, accounting for 98.1 and 97.7% of the total oil composition of the leaves and flowers, respectively. The main essential oil constituents were 1,8‐cineole, camphor, and L ‐fenchone, accounting for 33.54, 18.89, and 8.36% in the leaf oils and for 19.85, 23.33, and 7.13% in the flower oils, respectively. Besides this quantitative variation, the results also showed considerable qualitative variation between the essential oils of the two plant parts analyzed. These differences might be adaptative responses to ecological exigencies.     

Chemical Diversity in the Genus Alpinia (Zingiberaceae): Comparative Composition of Four Alpinia Species Grown in Northern India

The essential‐oil compositions of leaves, flowers, and rhizomes of Alpinia galanga (L.) Willd ., Alpinia calcarata Rosc ., Alpinia speciosa K. Schum. , and Alpinia allughas Rosc . were examined and compared by capillary GC and GC/MS. Monoterpenoids were the major oil constituents identified. 1,8‐Cineole, α‐terpineol, (E)‐methyl cinnamate, camphor, terpinen‐4‐ol, and α‐ and β‐pinenes were the major constituents commonly distributed in leaf and flower essential oils. The presence of endo‐fenchyl acetate, exo‐fenchyl acetate, and endo‐fenchol was the unique feature of rhizome essential oils of A. galanga, A. calcarata, and A. speciosa. On contrary, the rhizome oil of A. allughas was dominated by β‐pinene. Significant qualitative and quantitative variations were observed in essential‐oil compositions of different parts of Alpinia species growing in subtemperate and subtropical regions of Northern India. Cluster analysis was performed to find similarities and differences in essential‐oil compositions based on representative molecular skeletons. Monoterpenoids, viz., 1,8‐cineole, terpinen‐4‐ol, camphor, pinenes, (E)‐methyl cinnamate, and fenchyl derivatives, were used as chemotaxonomic markers.     

High Diversity of Indigenous Populations of Dalmatian Sage (Salvia officinalis L.) in Essential‐Oil Composition

Essential oils of 25 indigenous populations of Dalmatian sage (Salvia officinalis L.) that represent nearly half of native distribution area of the species were analyzed. Plantlets collected from wild populations were grown in the same field under the same environmental conditions and then sampled for essential‐oil analysis. The yield of essential oil ranged from 1.93 to 3.70% with average of 2.83%. Among the 62 compounds detected, eight (cis‐thujone, camphor, trans‐thujone, 1,8‐cineole, β‐pinene, camphene, borneol, and bornyl acetate) formed 78.13–87.33% of essential oils of individual populations. Strong positive correlations were observed between camphor and β‐pinene, β‐pinene and borneol, as well as between borneol and bornyl acetate. The strongest negative correlation was detected between camphor and trans‐thujone. Principal component analysis (PCA) on the basis of eight main compounds showed that first main component separated populations with high thujone content, from those rich in camphor, while the second component separated populations rich in cis‐thujone from those rich in trans‐thujone. Cluster analysis (CA) led to the identification of three chemotypes of S. officinalis populations: cis‐thujone; trans‐tujone, and camphor/β‐pinene/borneol/bornyl acetate. We propose that differences in essential oils of 25 populations are mostly genetically controlled, since potential environmental factors were controlled in this study.     

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.     

Chemical Composition and Antipathogenic Activity of Artemisia annua Essential Oil from Romania

The essential oil extracted by hydrodistillation from Romanian Artemisia annua aerial parts was characterized by GC/MS analysis, which allowed the identification of 94.64% of the total oil composition. The main components were camphor (17.74%), α‐pinene (9.66%), germacrene D (7.55%), 1,8‐cineole (7.24%), trans‐β‐caryophyllene (7.02%), and artemisia ketone (6.26%). The antimicrobial activity of this essential oil was evaluated by determining the following parameters: minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), minimal fungicidal concentration (MFC), and minimal biofilm eradication concentration (MBEC). Moreover, the soluble virulence factors were quantified with different biochemical substrates incorporated in the culture media. The reference and resistant, clinical strains proved to be susceptible to the A. annua oil, with MICs ranging from 0.51 to 16.33 mg/ml. The tested essential oil also showed good antibiofilm activity, inhibiting both the initial stage of the microbial cell adhesion to the inert substratum and the preformed mature biofilm. When used at subinhibitory concentrations, the essential oil proved to inhibit the phenotypic expression of five soluble virulence factors (hemolysins, gelatinase, DNase, lipases, and lecithinases). Briefly, the present results showed that the A. annua essential oil contained antimicrobial compounds with selective activity on Gram‐positive and Gram‐negative bacterial strains as well as on yeast strains and which also interfere with the expression of cell‐associated and soluble virulence factors.     

Chemical Composition and Antibacterial Activity of Iranian Lavandula × hybrida

Lavandin (Lavandula × hybrida) is an evergreen shrub and cultivated worldwide for its essential oil which possesses various biological activities. In this study, the essential oils were isolated from the leaves of ten lavandin populations in western Iran. The hydrodistilled essential oils were analyzed by GC‐FID/MS. Results indicated significant differences (P ≤ 0.05) among the various populations for the main essential oil constituents. The major components from different populations were 1,8‐cineole (31.64 – 47.94%), borneol (17.11 – 26.14%), and camphor (8.41 – 12.68%). In vitro antibacterial activity was evaluated against S. agalactiae, S. aureus, E. coli, and K. pneumoniae. The inhibition zones were in the range of 09.36 mm for S. aureus to 23.30 mm for E. coli. Results indicated that there was a significant correlation between essential oil composition and level of antibacterial efficacy expressed as inhibition zones.     

Genetic and Chemical Diversity in Perovskia abrotanoides Kar. (Lamiaceae) Populations Based on ISSRs Markers and Essential Oils Profile

Genetic and the essential oil composition variability among twelve Perovskia abrotanoides populations (PAbPs) growing wild in Iran were assessed by ISSR markers, GC‐FID and GC/MS, respectively. Nine selected ISSR primers produced 119 discernible bands, of them 96 (80.7%) being polymorphic. Genetic similarity values among populations ranged between 0.07 and 0.79 which indicated a high level of genetic variation. Polymorphic information content, resolving power and marker index generated by ISSR primers were, 0.31, 6.14, and 3.32, respectively. UPGMA grouped PAbPs into four main clusters. Altogether, 38 chemical compounds were identified in the oils, and a relatively high variation in their contents was found. Camphor (11.9 – 27.5%), 1,8‐cineole (11.3 – 21.3%), α‐bisabolol (0.0 – 13.1%), α‐pinene (5.9 – 10.8%), and δ‐3‐carene (0.1 – 10.5%) were the major compounds. Oxygenated monoterpenes (32.1 – 35.8%) and monoterpene hydrocarbons (25.7 – 30.4%) were the main groups of compounds in the oils studied. Cluster analysis and principal‐component analysis were used to characterize the samples according to oil components. Four main chemotypes were found to be Chemotype I (camphor/1,8‐cineol), Chemotype II (1,8‐cineole/camphor), Chemotype III (camphor/1,8‐cineol/α‐bisabolol), and Chemotype IV (camphor/δ‐3‐carene/α‐bisabolol). The information, provided here on P. abrotanoides populations, will be useful to introduce this plant into agricultural systems.     

Chemical Composition of Hydrodistilled Essential Oil of Artemisia incana (L.) Druce and Antimicrobial Activity against Foodborne Microorganisms

The oil obtained by hydrodistillation from the aerial parts of Artemisia incana (L.) Druce from Turkey was analyzed by GC and GC/MS. Sixty‐three compounds were characterized, representing 97.2% of the total components detected, and camphor (19.0%), borneol (18.9%), 1,8‐cineole (14.5%), bornyl acetate (7.8%), camphene (4.9%), and α‐thujone (4.8%) were identified as predominant components. The essential oil was also tested for its antimicrobial activity against 44 different foodborne microorganisms, including 26 bacteria, 15 fungi, and 3 yeast species. The essential oil of A. incana exhibited considerable inhibitory effects against all bacteria, fungi, and yeast species tested. However, the oil showed lower inhibitory activity against the tested bacteria than the reference antibiotics.     

Chemical Constituent,Antimicrobial Activity,and Synergistic Effect of the Stem,Leaf, and Flower Essential Oil of the Artemisia fragrans Willd. from Khoy

Artemisia fragrans is commonly used as a folk medicine as antispasmodic, anti-pyretic, anti-inflammatory, and abortifacient agents. The villagers use its pungent odor to repel rodents, mites, and pests, as well as its essential oil and smoke after burning to treat lung infections after uprooting the plant. Herein, we extracted the essential oils (EOs) of different parts of the plant and analyzed their chemical compositions and antibacterial activities. The chemical analysis led to the identification of 73, 59, and 57 compounds in the EOs of the stem, leaf, and flower, respectively. All of the EOs exhibited antibacterial activities against both G+ and G− bacteria. The EOs of the leaf and flower were more effective against tested bacteria, except B. anthracis and P. aeruginosa, compared to that of the stem. The binary combination of the EOs (stem and flower) or (stem and leaf) showed a synergistic effect. Statistical analysis indicated EOs of leaf and flower are more potent than that of the stem. These findings suggest the application of leaf and flower of the plant, which not only can prevent its uprooting but also ensure better therapeutic function.     

Essential Oils and Chemical Diversity of Southeast European Populations of Salvia officinalis L.

The essential oils of 25 populations of Dalmatian sage (Salvia officinalis L.) from nine Balkan countries, including 17 indigenous populations (representing almost the entire native distribution area) and eight non‐indigenous (cultivated or naturalized) populations were analyzed. Their essential‐oil yield ranged from 0.25 to 3.48%. Within the total of 80 detected compounds, ten (β‐pinene, 1,8‐cineole, cis‐thujone, trans‐thujone, camphor, borneol, trans‐caryophyllene, α‐humulene, viridiflorol, and manool) represented 42.60 to 85.70% of the components in the analyzed essential oils. Strong positive correlations were observed between the contents of trans‐caryophyllene and α‐humulene, α‐humulene and viridiflorol, and viridiflorol and manool. Principal component analysis (PCA) on the basis of the contents of the ten main compounds showed that four principal components had an eigenvalue greater than 1 and explained 79.87% of the total variation. Performing cluster analysis (CA), the sage populations could be grouped into four distinct chemotypes (A–D). The essential oils of 14 out of the 25 populations of Dalmatian sage belonged to Chemotype A and were rich in cis‐thujone and camphor, with low contents of trans‐thujone. The correlation between the essential‐oil composition and geographic variables of the indigenous populations was not significant; hence, the similarities in the essential‐oil profile among populations could not be explained by the physical proximity of the populations. Additionally, the southeastern populations tended to have higher EO yields than the northwestern ones.     

Yield,chemical composition,and bioactivity of essential oils from 12 species of Eucalyptus on Aedes aegypti larvae

The insecticidal activity of essential oils from 12 species of Eucalyptus (Myrtaceae) was evaluated on larvae of Aedes aegypti (L.) (Diptera: Culicidae), the most important vector of dengue and yellow fever in the Americas. Oils were obtained by hydrodistillation and their chemical composition was determined by gas chromatography coupled to mass spectrometry; yields ranged from 0.2 to 2.5%. Essential oils were mainly composed of 1,8‐cineole, α‐pinene, α‐phellandrene, β‐phellandrene, γ‐terpinene, 4‐terpineol, α‐terpineol, p‐cymene, and spathulenol. Larvicidal effects were tested on susceptible third or fourth stage Ae. aegypti larvae, determining median lethal concentration (LC₅₀) and median effective concentration (EC₅₀). Essential oils from Eucalyptus dunnii (Maiden), Eucalyptus gunnii (Hook), Eucalyptus tereticornis (Smith), Eucalyptus camaldulensis (Dehn), and Eucalyptus saligna (Smith) showed the best larvicidal activities with LC₅₀ values of 25.2, 21.1, 22.1, 26.8, and 22.2, respectively. No significant differences were observed between LC₅₀ and EC₅₀ values of the same oil. Regression analysis revealed a significant relationship between total essential oil yields and 1,8‐cineole concentration. Significant relationships were also revealed between larval mortality and the concentration of 1,8‐cineole and p‐cymene. This indicated that Eucalyptus species with high oil yields have higher 1,8‐cineole concentrations and lower p‐cymene concentrations and have less effect on Ae. aegypti. Our results suggest the potential of controlled crossing methods to obtain Eucalyptus trees with chemical profiles having enhanced activity against this mosquito.     

Essential‐Oil Diversity of Salvia tomentosa Mill. in Greece

Salvia tomentosa essential oils from Greece were studied for the first time here. The oils from five populations growing in Mediterranean pine forests on the island of Thassos (northern Aegean Sea) and from 14 populations situated in deciduous forests in Thrace (northeastern Greek mainland) were investigated. Their essential‐oil contents ranged from 1.1 to 3.3% (v/w, based on the dry weight of the plant material). The populations from Thassos had high contents of α‐pinene (18.0±2.9%), 1,8‐cineole (14.7±3.0%), cis‐thujone (14.0±6.9%), and borneol (12.8±2.2%) and smaller amounts of camphene, camphor, and β‐pinene, whereas the populations from Thrace showed high α‐pinene (16.7±4.0%), β‐pinene (22.8±4.5%), camphor (18.3±4.3%), and camphene (10.3±2.4%) contents, much lower 1,8‐cineole and borneol amounts, while cis‐thujone was completely lacking. The comparison of the present results with published data showed that oils having cis‐thujone as one of the main compounds were reported for the first time here. Multivariate statistical analyses indicate that the observed essential‐oil variation was related to geographical and environmental factors.     

Corymbia leaf oils,latitude, hybrids and herbivory: A test using common‐garden field trials

Foliar oils, particularly monoterpenes, can influence the susceptibility of plants to herbivory. In plants, including eucalypts, monoterpenes are often associated with plant defence. A recent analysis revealed an increase in foliar oil content with increasing latitudinal endemism, and we tested this pattern using three eucalypt taxa comprising a latitudinal replacement cline. We also examined the relative concentrations of two monoterpenes (α‐pinene and 1,8‐cineole), for which meta‐analyses also showed latitudinal variation, using hybrids of these three taxa with Corymbia torelliana. These, and pure C. torelliana, were then assessed in common‐garden field plots for the abundance and distribution of herbivory by four distinct herbivore taxa. Differing feeding strategies among these herbivores allowed us to test hypotheses regarding heritability of susceptibility and relationships to α‐pinene and 1,8‐cineole. We found no support for an increase in foliar oil content with increasing latitude, nor did our analysis support predictions for consistent variation in α‐pinene and 1,8‐cineole contents with latitude. However, herbivore species showed differential responses to different taxa and monoterpene contents. For example, eriophyid mites, the most monophagous of our censused herbivores, avoided the pure species, but fed on hybrid taxa, supporting hypotheses on hybrid susceptibility. The most polyphagous herbivore (leaf blister sawfly Phylacteophaga froggatti) showed no evidence of response to plant secondary metabolites, while the distribution and abundance patterns of Paropsis atomaria showed some relationship to monoterpene yields.     

The Essential Oil Compositions of Ocimum basilicum from Three Different Regions: Nepal,Tajikistan, and Yemen

The aerial parts of Ocimum basilicum L. were collected from four different geographical locations, Sindhuli and Biratnagar (Nepal), Chormaghzak village (Tajikistan), and Sana'a (Yemen). The essential oils were obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry. A cluster analysis of 179 essential oil compositions revealed six major chemotypes: Linalool, eugenol, estragole, methyl eugenol, 1,8‐cineole, and geraniol. All four of the basil oils in this study were of the linalool‐rich variety. Some of the basil oils were screened for bioactivity including antimicrobial, cytotoxicity in human cancer cells, brine shrimp lethality, nematicidal, larvicidal, insecticidal, and antioxidant. The basil oils in this study were not notably antibacterial, cytotoxic, antioxidant, nor nematicidal, but were active in the brine shrimp lethality test, and did show larvicidal and insecticidal activities.