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.     

Composition and intraspecific chemical variability of the essential oil from Artemisia herba-alba growing wild in a Tunisian arid zone

The intraspecific chemical variability of essential oils (50 samples) isolated from the aerial parts of Artemisia herba-alba Asso growing wild in the arid zone of Southeastern Tunisia was investigated. Analysis by GC (RI) and GC/MS allowed the identification of 54 essential oil components. The main compounds were β-thujone and α-thujone, followed by 1,8-cineole, camphor, chrysanthenone, trans-sabinyl acetate, trans-pinocarveol, and borneol. Chemometric analysis (k-means clustering and PCA) led to the partitioning into three groups. The composition of two thirds of the samples was dominated by α-thujone or β-thujone. Therefore, it could be expected that wild plants of A. herba-alba randomly harvested in the area of Kirchaou and transplanted by local farmers for the cultivation in arid zones of Southern Tunisia produce an essential oil belonging to the α-thujone/β-thujone chemotype and containing also 1,8-cineole, camphor, and trans-sabinyl acetate at appreciable amounts.     

Chemical compositions,antimicrobial and herbicidal effects of essential oils isolated from Turkish Tanacetum aucheranum and Tanacetum chiliophyllum var. chiliophyllum

The chemical composition of essential oils isolated from the aerial parts by hydrodistillation of Turkish Tanacetum aucheranum and Tanacetum chiliophyllum var. chiliophyllum were analyzed by GC–MS. The oils contain similar major components. The major components of T. aucheranum oil were 1,8-cineole (23.8%), camphor (11.6%), terpinen-4-ol (7.2%), α-terpineol (6.5%), borneol (3.8%), (E)-thujone (3.2%), epi-α-cadinol (3.1%), and artemisia ketone (3.0%). Camphor (17.9%), 1,8-cineole (16.6%) and borneol (15.4%) were found to be predominant constituents in the oil of T. chiliophyllum. It is interesting to find that ester derivatives of dihydro-α-cyclogeranic acid (2,2,6-trimethylcyclohexylcarboxylate), dihydro-α-cyclogeranyl hexanoate (10.1%), dihydro-α-cyclogeranyl pentanoate (3.0%), dihydro-α-cyclogeranyl butanoate (2.1%) and dihydro-α-cyclogeranyl propionate (1.2%) are firstly found as chemotaxonomically important components in T. chiliophyllum oil. From these, dihydro-α-cyclogeranyl hexanoate was isolated on silica gel column chromatography and its structure was confirmed by spectroscopic methods. This is the first report on the occurrence of ester derivatives of dihydro-α-cyclogeranic acid in essential oils of Tanacetum species. The oils were also characterized to have relatively high amounts of oxygenated monoterpenes. Results of the antifungal testing by microbial growth inhibition assays showed that the oils completely inhibit the growth of 30 phytopathogenic fungi. However, their growth inhibition effects were lower than commercial benomyl. The oils tested for antibacterial activity against 33 bacterial strains showed a considerable antibacterial activity over a wide spectrum. Herbicidal effects of the oils on seed germination of Amaranthus retroflexus, Chenopodium album and Rumex crispus were also determined and the oils completely inhibited the seed germination and seedling growth of the plants.     

Variation of Salvia fruticosa Essential Oils on the Island of Crete (Greece)

The essential oil content and composition of Salvia fruticosa (Greek sage) plants growing wild in 20 localities scattered on the island of Crete are studied. The results of our analyses have shown a noticeable variation in the essential oil content (ranging from 1.1 up to 5.1 %) and the amount of the four main oil components: 1,8-cineole (22.7 ? 64.2% of total oil), α-thujone (1.0 ? 19.2%) β-thujone (0.9 ? 25.6%) and camphor (0.8 ? 30.3%). Discriminant analysis revealed that the variation pattern of the essential oil content and the amount of the four main oil components is geographically related, following a W → E direction. Plants grown in Western Crete show a lower essential oil content and their oils are characterised by the predominance of 1,8-cineole. On the other hand, those collected from Eastern Crete exhibit higher values in essential oil content and their oils, besides 1,8-cineole, are rich in α- and β-thujone or camphor. Our findings are further discussed in relation to literature data.     

栽培地区、采收季节和株龄对迷迭香精油成分和抑菌活性的影响

采用气相色谱-质谱联用的方法,研究了不同提取部位、栽培地区、采收季节和株龄对迷迭香精油提取率、成分和抑菌活性的影响。结果表明,在贵州栽培的迷迭香叶子中精油的主要成分为α-蒎烯（31.88%–39.09%）、1,8-桉叶素（8.82%–10.97%）和樟脑（7.63%–11.59%）;茎中精油的主要成分为龙脑（26.62%–39.05%）、樟脑（11.41%–15.27%）和α-蒎烯（7.23%–17.80%）;茎中精油的抑菌活性强于叶中精油。北京地区栽培的迷迭香,其叶子中精油的主要成分为樟脑（27.92%）和L-β-蒎烯（25.28%）,抑菌活性强;茎中精油和贵州栽培的成分和活性均相似。对于采收季节,夏季采收的迷迭香精油提取率高,抑菌活性强。而株龄对精油的成分和抑菌活性影响不大。该研究为我国引种迷迭香的合理配置栽培、采收、生产条件和高效开发利用其抑菌活性提供了科学的依据。     

Genetic resources of Tunisian Artemisia arborescens L. (Asteraceae), pattern of volatile metabolites concentration and bioactivity and implication for conservation

Artemisia arborescens L. (Asteraceae) is an endemic and a valuable medicinal and ornamental species in the Mediterranean regions. Despite the interest given to A. arborescens L. as promising medicinal crop, this species is becoming threatened of extinction in Tunisia as a result of the fragmentation of its habitat and the absence of any specific measures for its conservation and valorisation. Based on the last considerations, extent information about their volatile metabolites profiling, contents and antimicrobial potential were undertaken based on fourteen populations originated from various geographical and bioclimatic habitats of Tunisia. The obtained results reveal an essential oil content mean value of 1.47%. The leaves of Tunisian tree wormwood populations were dominated by camphor (15.05–58.05%), chamazulene (11.72–45.26%) and β-thujone (0–36.53%). Based on the three first major compounds detected for each population, four different oil types were defined (Oil type I: camphor-chamazulene-β-thujone; Oil type II: camphor-chamazulene-terpinen-4-ol; Oil type III: camphor-chamazulene-bornyl acetate; Oil type IV: camphor-chamazulene-linalool). PCA, HCA and Heatmap chemometric analyses revealed three classification clusters defined mainly by minor compounds. These minor volatile metabolites succeed to discriminate among the fourteen studied populations which promote their chemotaxonomic interest. Our findings confirm previous reports concerning this species in the world and show chamazulene, camphor and β-thujone as the major compounds of this species which define their well known chemotypes independently of the geographical, bioclimatic and genotypic factors. This makes of these three components promising chemosystematic tool for the discrimination of A. arborescens L. in the genus Artemisia. The results showed that the four tested oils were effective against the nine tested microbial strains. The highest antimicrobial potential was revealed for the population AAr_MB characterized by camphor, chamazulene and β-thujone as the dominant components. The pattern of essential oils concentration offers wide range of possibilities for the initiation of breeding programs according to the desired bioactive compounds. Both in situ and ex situ conservation strategies were suggested for the maintenance of the highest chemical polymorphism of this valuable medicinal species.     

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.     

Dr. Alfred Jeske 75 jahre

The chemical composition, phytotoxic and antifungal activities of the essential oils isolated by hydrodistillation from the needles of Tunisian Aleppo pine harvested from different provenances were evaluated. The chemical composition analysed by gas chromatography/mass spectrometry (GC/MS) revealed variability among provenances displaying interesting chemotypes, (Z)-caryophyllene (16.16–28.9%), β-myrcene (8.5–22.9%), α-pinene (11.7–13.14%), β-pinene (3.13–11.8%), bicyclogermacrene (5.2–12.37%), α-terpinolene (8.11–11.01%) and α-humulene (2.85–5.2%), which were the main components in the oil. Antifungal ability of Aleppo pine oils was tested by disc agar diffusion against 10 phytopathogenic fungi. Weak antifungal activity was observed for the essential oils isolated. Furthermore, in contrast, the herbicidal activity investigated for three common weeds in Tunisian cereal crops was very strong and seed germination was inhibited at a low concentration and their herbicidal effects were higher than those of a commercial herbicide.     

Variation in morphological characters,chemical composition,and anthocyanin content of different Chrysanthemum morifolium cultivars from Iran

The morphological traits, essential oil composition, and anthocyanin content of 17 Iranian C. morifolium cultivars were evaluated. Based on Shannon diversity index (I), such morphological characters as flower head diameter, ray floret, shape of apex, and main color of ray floret revealed more variability than the other traits. Significant genotypic variations were also observed in essential oil content (ranging from 0.1 to 0.56% (w/w)) and composition. Gas chromatography-mass spectrometry (GC-MS) analysis of the essential oil was conducted to identify 47 compounds in which camphor (0–44.6%), chrysanthenone (0–48.96%), chrysanthenyl acetate (0–16.22%), verbenol (0–11.78%), (+)-5-epi-neointermedeol (0–25.41%), and aromadendrene (0–14.98%) were the main constituents. Results of cluster analysis of essential oil compositions divided the cultivars into four groups. Hybridization among cultivars of divergent clusters led to heterotic effects for flower quality and phytochemical characters. The relationships established between the components revealed high correlations of anthocyanin with the two major aroma compounds of verbenol and chrysanthenyl acetate while they also provided a clue to the association between aroma compounds and color pigmentation. Moreover, a correlation was established between chrysanthenone and flower head diameter (r = −0.502). Based on the results obtained, it might be suggested that smaller flowers are capable of accumulating higher amounts of chrysanthenone. Clearly, the associations between morphological traits and essential oil components provide new insights for improved breeding programs in chrysanthemum.     

Chemical Composition and Biological Activities of the Essential Oil from Leaves and Flowers of Pulicaria incisa sub. candolleana (Family Asteraceae)

The composition of the essential oil isolated from leaves and flowers of Pulicaria incisa sub. candolleana E. Gamal ‐Eldin , growing in Egypt, was analysed by GC and GC‐MS. Forty‐nine and 68 compounds were identified from the oils of the leaves and flowers accounting for 86.69 and 84.29%, respectively of the total detected constituents. Both leaves and flowers oils were characterized by the high content of carvotanacetone with 66.01, 50.87 and chrysanthenone 13.26, 24.3%, respectively. The cytotoxic activity of both essential oils was evaluated against hepatocellular carcinoma cell line HEPG‐2, using MTT assay and vinblastine as a reference drug. Leaf oil showed higher activity with IC₅₀ 11.4 μg/ml compared with 37.4 μg/ml for flower oil. The antimicrobial activity of both oils was evaluated using agar well diffusion method towards two representatives for each of Gram positive and Gram negative bacteria as well as four representatives for fungi. The minimum inhibitory concentration of both essential oils against bacterial and fungal strains was obtained in the range of 0.49 – 15.63 μg/ml.     

The inflorescence and leaf essential oils of Tanacetum vulgare L. var. vulgare growing wild in Lithuania

Forty samples of inflorescences and leaves of wild Tanacetum vulgare L. var. vulgare were collected in 20 habitats from Lithuania. The essential oils were analyzed by GC and GC/MS. The 57 identified compounds in the oils made up 80.7–99.6%. According to the cluster analysis the volatile oils were divided into four groups with 1,8-cineole (23.6–46.3%, 11 oils), trans-thujone (35.7–78.4%, 6 samples), camphor (19.8–61.8%, 17 oils) and myrtenol (13.1–24.9%, 6 samples) as main constituents. The inflorescences and leaves of tansy plants formed the oils with the same dominating constituent in 15 of the 20 habitats investigated. The leaves in five localities produced oils of the 1,8-cineole chemotype, while the inflorescences biosynthesized oils of the camphor type in three habitats and of the myrtenol type in two habitats. Amounts of the 1,8-cineole in all leaf oils were greater than that in inflorescence oils of the plants from the same locality. An opposite correlation was determined for camphor, myrtenol, cis- and trans-thujone. The myrtenol chemotype was not noticed earlier in the essential oils of T. vulgare.     

Essential oil composition and antimicrobial activity of Diplotaenia damavandica

Antimicrobial activity of the essential oils obtained from leaves, root and the seeds of Diplotaenia damavandica Mozaffarian, Hedge & Lamond, an endemic plant to Iran, was determined against 10 microorganisms using the disk susceptibility test as well as measuring minimum inhibitory concentrations. The results showed that all three oils had antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli. The essential oil from the leaves had the highest antimicrobial activity against all test microorganisms including the fungal strains. The essential oils compositions were analyzed and determined by GC and GC-MS. The oils analyses resulted in the identification of 16, 17 and 20 compounds representing 94.2%, 96.4% and 95.1% of the total oils, respectively. The main components of the leaf essential oils were (Z)-beta-ocimene (21.6%), alpha-phellandrene (21.3%) and terpinolene (20%). Dill apiol (30.1%) and gamma-terpinene (16.2%) were the main components of the root and seed essential oils, respectively.     

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.     

Castor and camphor essential oils alter hemocyte populations and induce biochemical changes in larvae of Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae)

Two plant essential oils; camphor and castor were tested for insecticidal and antifeedant activity against the 4th instar larvae of Spodoptera littoralis, a serious pest on cotton in Egypt. Also the impact of LC₁₀ of both oils on some physiological parameters in larvae was studied by using leaf dipping technique. Analysis of both oils using GC–MS revealed several insecticidal and antifeedant compounds. Our results showed higher insecticidal activity and antifeedant index of camphor oil against S. littoralis. The LC₅₀ and the antifeedant indices were 163.1, 246.8?mg/ml and 12.69, 6.62% for camphor and castor bean oil, respectively. The total hemocyte count (THC) and differential hemocyte count (DHC) were reduced significantly after 48?h of treatment compared to controls. Both oils reduced all types of hemocytes except plasmatocytes which were reduced only by castor oil. Camphor oil decreased total proteins and carbohydrates while castor oil targeted only carbohydrate content. Both oils didn't affect the amount of total lipids. Lipase, α-amylase and glucose-6-phosphate dehydrogenase (G6PD) enzyme activities were increased significantly in larvae treated with camphor oil than other treatments. These results clearly indicate that castor and camphor oils can affect the nutritional status in S. littoralis larvae, thereby changing the internal metabolic processes in the larvae which make them as potential control agents in IPM programs against S. littoralis.     

Evaluation of Antibacterial Activity of Lavandulapedunculata subsp. atlantica (Braun‐Blanq.) Romo Essential Oil and Selected Terpenoids against Resistant Bacteria Strains–Structure–Activity Relationships

The genus Lavandula is known for its different uses in traditional medicine. This study is interested in the chemical composition of Lavandulapedunculata subsp.atlantica (Braun‐Blanq. ) Romo as well as evaluating its antibacterial potential against multi‐resistant strains. The analysis of Lavandulaatlantica essential oil (LAEO) allows the identification of 47 components representing 93.6 % of all identified. The main constituent of LAEO was camphor (50.4 %), followed by fenchone (14.1 %) and camphene (5.6 %). The antibacterial assays revealed that LAEO was active against all the studied bacteria. A preliminary study of the relationship between certain terpenoids and antibacterial activity was also carried out in order to note the compound(s) that are responsible for LAEO's antibacterial activity. This study showed that the activity of the essential oil may be due to the presence of certain minor compounds such as carvone, considering the presence of the synergistic effect between the essential oil.     

Composition of the essential oils of Tanacetum argyrophyllum (C. Koch) Tvzel. var. argyrophyllum and Tanacetum parthenium (L.) Schultz Bip. (Asteraceae) from Turkey

The aerial parts of Tanacetum argyrophyllum (C. Koch) Tvzel. var. argyrophyllum and T. parthenium (L.) Schultz Bip. were hydro-distilled to produce the oils in the yields of 0.78% (v/w) and 0.43% (v/w), respectively. The oils were analysed by GC and GC/MS. Twenty-two and twenty-three components were identified representing 94.2% and 90.1% of the oils, respectively. The main compounds of T. argyrophyllum were cis-thujone (69.9%), trans-thujone (5.6%) and 1,8-cineole (3.2%), whereas camphor (56.9%), camphene (12.7%) and p-cymene (5.2%) were the major constituents of T. parthenium.     

Chemical and Biological Evaluation of Hypericum maculatum Crantz Essential Oil

The chemical composition and the antimicrobial activity of the essential oil isolated from the aerial parts of Hypericum maculatum Crantz were determined. In total, 109 compounds were identified, with germacrene D (21.5%), nonane (6.5%), (E)‐β‐farnesene (5.3%), δ‐cadinene (4.5%), and ledol (4.4%) as the main constituents. The chemical compositions of this oil and of four previously studied H. maculatum oils were compared using multivariate statistical analyses, viz., agglomerative hierarchical cluster and principal component analyses. Based on the results, the interrelationship among the hitherto studied H. maculatum oil samples, including the oil characterized here, was discussed. The study of the antimicrobial potential of the oil against five bacterial and two fungal strains showed that the oil had mainly moderate antimicrobial effects.     

Screening of antibacterial activities of twenty-one oxygenated monoterpenes

Plant essential oils are widely used as fragrances and flavours in the cosmetic, perfume, drug and food industries. Oxygenated monoterpenes are widespread components of the essential oils, usually occurring in high amount. In this paper, the antibacterial activities of twenty-one oxygenated monoterpenes (borneol, borneol acetate, camphor, carvone, 1,8-cineole, citronellal, beta-citronellol, dihydrocarvone, fenchol, fenchone, geraniol acetate, isomenthol, limonene oxide, linalool, linalool acetate, nerol, nerol acetate, terpinen-4-ol, alpha-terpineol, menthol and menthone) and penicillin (standard antibiotic) were determined using a disc diffusion method (in vitro) against 63 bacterial strains, belonging to 37 different genera and 54 species (plant, food and clinic origins). The results showed that the oxygenated monoterpenes exhibited a variable degree of antibacterial activities. These compounds also inhibited the growth of bacterial strains by producing a weak zone of inhibition from 7 to 11 mm in diameter, depending on the susceptibility of the tested bacteria. Among the tested compounds, nerol, linalool alpha-terpineol, fenchol and terpinen-4-ol showed antibacterial activity at a broad spectrum. However, their antibacterial activities were lower than those of penicillin. In contrast to these compounds, camphor and 1,8-cineole exhibited no inhibition effects on the growth of all tested bacteria.     

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.     

The composition and antibacterial activity of essential oils in three Ocimum species growing in Romania

In this study the glandular hair morphology, chemical composition and antimicrobial activity of the essential oils from three Ocimum species have been investigated (Ocimum basilicum L. var. Genovese, O. gratissimum and O. tenuiflorum). The indumentum shows little variation among the investigated species with both glandular and non-glandular hairs presents. Glandular hairs on the three species are peltate and capitate (with various cell numbers in the stalk and gland). The samples of essential oils obtained from the plant aerial organs by hydrodistillation have been analyzed by GC-MS. Linalool (65.38%, 74.22%, 38.60%), eugenol (5.26%, 3.47%, 10.20%) and tau-cadinol (8.18%, 3.47%, 10.20%) appear as the main components in Ocimum basilicum L. var. Genovese, O. gratissimum and O. tenuiflorum. The oils also contain lower levels of α-bergamotene, 1,8-cineole, germacrene D, β-ocimene, α-caryophyllene, camphor, and α-guaiene. All essential oils showed antibacterial activity against Staphylococcus aureus and Escherichia coli depending on their concentration. Ocimum basilicum L. var. Genovese oil produced the strongest antibacterial effect on S. aureus and E. coli.