Composition and the in vitro antimicrobial activities of the essential oils of some Thymus species

The genus Thymus (Lamiaceae) is represented by 38 species (64 taxa) in Turkey, and 24 of which are endemic to Turkey. Aerial parts of Thymus longicaulis subsp. chaubardii var. chaubardii, T. zygioides var. lycaonicus, T. longicaulis subsp. longicaulis var. subisophyllus and T. pulvinatus collected from three different localities in Balikesir province were subjected to hydrodistillation to yield essential oils which were subsequently analysed by GC and GC/MS. The main constituents of the oils were identified, and antimicrobial bioassay was applied. Thymol (56.6%, 42.8%, 36.9%) was the main component in the oils of T. longicaulis subsp. chaubardii var. chaubardii (chemotype I), T. longicaulis subsp. chaubardii var. chaubardii (chemotype II) and T. zygioides var. lycaonicus respectively. The oil of T. longicaulis subsp. longicaulis var. subisophyllus contained carvacrol (60.0%) and the oil of T. pulvinatus borneol (27.9%) as main constituents.     

Phytochemical analysis and in vitro antiviral activities of the essential oils of seven Lebanon species

The chemical composition of the essential oils of Laurus nobilis, Juniperus oxycedrus ssp. oxycedrus, Thuja orientalis, Cupressus sempervirens ssp. pyramidalis, Pistacia palaestina, Salvia officinalis, and Satureja thymbra was determined by GC/MS analysis. Essential oils have been evaluated for their inhibitory activity against SARS-CoV and HSV-1 replication in vitro by visually scoring of the virus-induced cytopathogenic effect post-infection. L. nobilis oil exerted an interesting activity against SARS-CoV with an IC(50) value of 120 microg/ml and a selectivity index (SI) of 4.16. This oil was characterized by the presence of beta-ocimene, 1,8-cineole, alpha-pinene, and beta-pinene as the main constituents. J. oxycedrus ssp. oxycedrus oil, in which alpha-pinene and beta-myrcene were the major constituents, revealed antiviral activity against HSV-1 with an IC(50) value of 200 microg/ml and a SI of 5.     

Essential‐Oil Composition,Antileishmanial, and Toxicity Study of Artemisia abyssinica and Satureja punctata ssp. punctata from Ethiopia

Essential oils of Artemisia abyssinica and Satureja punctata ssp. punctata from Ethiopia were analyzed by GC and GC/MS, and screened for leishmanicidal activity against promastigote and axenic amastigotes of Leishmania donovani and L. aethiopica, including toxicity studies on human monocytic leukemia cells (THP‐1) and erythrocytes in vitro. GC/MS of A. abyssinica oil revealed 67 compounds (99.94%) with the major constituents yomogi alcohol (38.47%), artemisyl acetate (24.88%), and artemisia alcohol (6.70%), and oxygenated monoterpenes (84.00%) as the dominant group. The oil of S. punctata contained 67 compounds (99.49%) with the main constituents geranial (27.62%), neral (21.72%), α‐bisabolol (13.62%), and (E)‐nerolidol (4.82%), of which oxygenated mono‐ and sesquiterpenes (58.39 and 26.91%, resp.) showed highest abundance. Both oils showed effect on promastigotes (MIC 76.5 to 312.5 nl/ml) and amastigotes (EC₅₀ 4.06 to 131.00 nl/ml) of L. donovani and L. aethiopica, and varying toxicities on THP‐1 cells (CC₅₀ 0.013 to 350 nl/ml with selectivity index between 0.001 and 28) and erythrocytes (with LC₅₀ 0.35 to 1.52 μl/ml). S. punctata oil exerted highest activity against both Leishmania sp. and toxicity. The revealed antileishmanial activities support further isolation and investigation of oil constituents for in vitro/in vivo evaluation.     

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.     

Chemotaxonomic and Micromorphological Traits of Satureja montana L. and S. subspicata Vis. (Lamiaceae)

Satureja montana and S. subspicata are used as spice, pepper substitute, for preparing tea, juice, and as a medicine. Fourteen populations (seven per species) of Satureja montana L. and S. subspicata Vis . growing in Croatia were examined to determine the chemical composition of the essential oil (analyzed by GC‐FID and GC/MS), the content of macroelements (Na, K, Ca, Mg) and trace elements (B, Fe, Cu, Mn, Zn, Al, Pb, Cr, Cd, Ni, Hg, As) analyzed by ICP‐AES, antioxidant compounds (analyzed by UV/VIS spectrophotometer), and the types and distribution of trichomes (analyzed by scanning electron microscopy). The main constituents of the essential oil were carvacrol and thymol in S. montana (all populations belong to one phenol chemotype), while α‐eudesmol, β‐eudesmol, and spathulenol dominated in S. subspicata (three chemotypes could be distinguished). Both species possess considerably higher quantities of Ca and Mg, and moderate concentrations of K and Na, while Hg and As levels were below the limit of quantification. Non‐glandular trichomes, peltate trichomes, and three types of capitate trichomes were observed on leaves, stem, calyx, and corolla.     

Chemical composition and antimicrobial activity of the essential oils of the Amazon Guatteriopsis species

The essential oils of Guatteriopsis blepharophylla, Guatteriopsis friesiana and Guatteriopsis hispida were obtained by hydrodistillation and analysed by GC and GC/MS. The main compound found in the leaf oil of G. blepharophylla was caryophyllene oxide (1) (69.25%). The leaf oil of G. friesiana contained predominantly beta-eudesmol (2) (51.60%), gamma-eudesmol (3) (23.70%), and alpha-eudesmol (4) (14.56%). The major constituents identified in the leaf of G. hispida were beta-pinene (38.18%), alpha-pinene (30.77%) and (E)-caryophyllene (20.59%). The antimicrobial activity of the essential oils was evaluated against 11 species of microorganisms. The oil of G. friesiana exhibited significant antimicrobial activity for all microorganisms tested, whereas that of G. hispida and G. blepharophyla had potent activity against Rhodococcus equi with MIC of 50 microg mL(-1). The major constituents of each oil were also tested separately, and showed lower activity compared to the oils. Moreover, mixtures of the main constituents, in the same proportions found in G. friesiana and G. hispida oils, did not show the same activity as the original oils.     

Chemical Composition and Antimicrobial Activity of Satureja,Thymus, and Thymbra Species Grown in Lebanon

The essential oils were extracted by hydrodistillation from Satureja cuneifolia, Satureja thymbra, Coridothymus capitatus, Thymus syriacus, and Thymbra spicata growing wild in Lebanon. Their phytochemical analysis performed by GC/MS showed that the aforementioned species are characterized either by carvacrol (60.9%) or thymol (54.3%) or by a more or less equal amounts of these two phenols. Assessment of their in vitro antimicrobial activity against Candida albicans and six pathogenic bacteria using the broth dilution method revealed that the tested oils have a broad activity spectrum with minimum inhibitory concentration ranging from 0.1 to 0.8 mg/ml. Among the tested species, S. thymbra EO showed the highest antimicrobial potential whereas T. syriacus showed the lowest inhibitory activity. These results give scientific evidence for the use of those species in the Lebanese folk medicine and lend support to implement them as natural alternatives for synthetic antimicrobials.     

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.     

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.     

Comparison of the volatile composition of Stachys persica Gmel. and Stachys byzantina C. Koch. oils obtained by hydrodistillation and steam distillation

The oils obtained by hydrodistillation and steam distillation of the aerial parts of Stachys persica Gmel. and Stachys byzantina C. Koch grown in Iran were analyzed by GC/MS. The essential oil obtained by hydrodistillation of the aerial parts of S. persica was characterized by a high amount of non-terpenoid components of which methyllinoleate (27.7%), hexadecanoic acid (9.8%) and 6,10,14-trimethyl-2-pentadecanone (9.2%) were the major constituents, whereas the steam distilled oil of the plant contained hexadecanoic acid (27.2%), carvacrol (9.4%) and eugenol (5.2%). Both hydrodistilled and steam distilled essential oils of the aerial parts of S. byzantina were rich in sesquiterpenes such as a-copaene (16.6% and 10.4%), spathulenol (16.1% and 18.5%) and beta-caryophyllene (14.3% and 13.5%), respectively.     

Nematicidal activity of essential oils and volatiles derived from Portuguese aromatic flora against the pinewood nematode, Bursaphelenchus xylophilus

Twenty seven essential oils, isolated from plants representing 11 families of Portuguese flora, were screened for their nematicidal activity against the pinewood nematode (PWN), Bursaphelenchus xylophilus. The essential oils were isolated by hydrodistillation and the volatiles by distillation-extraction, and both were analysed by GC and GC-MS. High nematicidal activity was achieved with essential oils from Chamaespartium tridentatum, Origanum vulgare, Satureja montana, Thymbra capitata, and Thymus caespititius. All of these essential oils had an estimated minimum inhibitory concentration ranging between 0.097 and 0.374 mg/ml and a lethal concentration necessary to kill 100% of the population (LC(100)) between 0.858 and 1.984 mg/ml. Good nematicidal activity was also obtained with the essential oil from Cymbopogon citratus. The dominant components of the effective oils were 1-octen-3-ol (9%), n-nonanal, and linalool (both 7%) in C. tridentatum, geranial (43%), neral (29%), and β-myrcene (25%) in C. citratus, carvacrol (36% and 39%), γ-terpinene (24% and 40%), and p-cymene (14% and 7%) in O. vulgare and S. montana, respectively, and carvacrol (75% and 65%, respectively) in T. capitata and T. caespititius. The other essential oils obtained from Portuguese flora yielded weak or no activity. Five essential oils with nematicidal activity against PWN are reported for the first time.     

Chemical diversity of volatiles of Teucrium orientale L. var. orientale, var. puberulens, and var. glabrescens determined by simultaneous GC-FID and GC/MS techniques

In the present work, three varieties of Teucrium orientale, var. orientale, var. puberulens, and var. glabrescens, were collected and investigated for chemical composition of the oils. Subsequent gas chromatography (GC-FID) and gas chromatography coupled to mass spectrometry (GC/MS) revealed high abundance of sesquiterpenes in the essential oils analyzed. All the oils contained β-caryophyllene (22.6, 8.5, and 6.3%, resp.) and hexadecanoic acid (7.9, 12.8, and 13.1%). Germacrene D (24.6 and 33.4%) and bicyclogermacrene (6.7 and 8.5%) were found to be the main constituents of var. orientale and var. puberulens, respectively. The high percentages of β-cubebene (26.9%), α-cubebene (9.0%), and α-copaene (7.2%) established the diversity of var. glabrescens. The qualitative difference between the essential oils allowed the differentiation between the varieties in agreement with the morphological observations described in Flora of Turkey for each variety studied. In addition, a cluster analysis of twelve Teucrium taxa based on the essential-oil composition has been carried out. Hovewer, the analysis did not clearly reflect the infrageneric classification of the genus, it largely confirmed the relationships between the infraspecific taxa of Teucrium orientale and T. chamaedrys.     

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.     

Antibacterial activity and chemical composition of the essential oil of Grammosciadium platycarpum Boiss. from Iran

The chemical composition of the essential oils obtained from two samples (GP1 and GP2) of Grammosciadium platycarpum Boiss. was analyzed by GC and GC-MS. The analysis of the oils resulted in the identification of twenty-two constituents. Linalool (79.0%-GP1, 81.8%-GP2) and limonene (10.0%, 5.8%) were found to be the major components, respectively. The in vitro antibacterial activities of these oils and their main compounds against seven Gram-positive and Gram-negative bacteria were investigated. The results exhibited that the total oils and their major components possess strong to moderate activities against all the tested bacteria except for Pseudomonas aeruginosa.     

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.     

正交设计优选超声辅助提取柑桔叶精油工艺研究

采用溶剂萃取法提取柑桔叶中的精油,并优化工艺条件。通过气相色谱、质谱等仪器对所提取的精油组分进行鉴定分析。最终得到最佳提取条件:用6倍石油醚浸泡4 h,超声60次,可得到较好产率,产率1.73%。利用气相色谱-质谱联用法对柑橘叶精油的化学组成进行分析,用归一化法测定其相对百分含量,共分离出387种成分,鉴定了其中的32种成分,占出峰物质总量的70.22%,主要成分为β-氧化石竹烯(10.15%)、十六烷酸(8.15%)、芳樟醇(6.31%)、α-甜橙醛(4.33%)、亚油酸(6.48%)、视黄醛(4.04%)等成分。     

Chemical composition of essential oils from leaves of Helicteres guazumifolia (Sterculiaceae), Piper tuberculatum (Piperaceae), Scoparia dulcis (Arecaceae) and Solanum subinerme (Solanaceae) from Sucre, Venezuela

Essential oils, biosynthesized and accumulated in aromatic plants, have a wide range of applications in the pharmaceutical health, cosmetics, food and agricultural industry. This study aimed to analyze the secondary metabolites in some plant species in order to contribute to their chemotaxonomy. Leaves from Helicteres guazumifolia, Piper tuberculatum, Scoparia dulcis and Solanum subinerme were collected and their essential oils were obtained by means of hydro-distillation. The oil fraction was analyzed and identified by GC/MS. The extraction yields were of 0.004, 0.032, 0.016 and 0.005%, and the oil constituents of 88.00, 89.80, 87.50 and 89.47%, respectively. The principal oils found were: non-terpenoids volatile secondary metabolites (30.28%) in H. guazumifolia; sesquiterpenoids (20.82 and 26.09%) and oxigen derivated (52.19 and 25.18%) in P. tuberculatum and S. dulcis; and oxigen diterpenoids (39.67%) in S. subinerme. The diisobuthylphtalate (13.11%) in H. guazumifolia, (-)-spathulenol (11.37%) in P. tuberculatum and trans-phytol (8.29 and 36.00%) in S. dulcis and S. subinerme, were the principal constituents in their respective essential oils. The diisooctylphtalate were the essential oil common to all species, but the volatile compounds such as trans-pinane, L-linalool, beta-ionone, isophytol, neophytadiene, trans-phytol, dibutylphtalate and methyl hexadecanoate, were only detected in three of these essences. This suggests that these plants may require similar secondary metabolites for their ecological interactions, possibly due to common environmental factors.     

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。     

Antifungal and Herbicidal Effects of Fruit Essential Oils of Four Myrtus communis Genotypes

The chemical composition of the essential oils isolated by hydrodistillation from the fruits of four selected Myrtus communis L. genotypes from Turkey was characterized by GC‐FID and GC/MS analyses. 1,8‐Cineole (29.20–31.40%), linalool (15.67–19.13%), α‐terpineol (8.40–18.43%), α‐pinene (6.04–20.71%), and geranyl acetate (3.98–7.54%) were found to be the major constituents of the fruit essential oils of all M. communis genotypes investigated. The oils were characterized by high amounts of oxygenated monoterpenes, representing 73.02–83.83% of the total oil compositions. The results of the fungal growth inhibition assays showed that the oils inhibited the growth of 19 phytopathogenic fungi. However, their antifungal activity was generally lower than that of the commercial pesticide benomyl. The herbicidal effects of the oils on the seed germination and seedling growth of Amaranthus retroflexus L., Chenopodium album L., Cirsium arvense (L.) Scop ., Lactuca serriola L., and Rumex crispus L. were also determined. The oils completely or partly inhibited the seed germinations and seedling growths of the plants. The findings of the present study suggest that the M. communis essential oils might have potential to be used as natural herbicides as well as fungicides.     

The inhibition of Candida albicans by selected essential oils and their major components

Many volatile oils are known to possess antifungal properties and are potentially applicable as antimycotic agents. By studying the efficacy of essential oils against different pathogenic mycetes, we have evaluated the in-vitro inhibiting activity of some essential oils and their main constituents against a strain of Candida albicans. Sixteen commercial essential oils and forty-two pure constituents (alcohols, aldehydes, ketons, phenols and hydrocarbons), were tested by using a semisolid agar antifungal susceptibility (SAAS) method. Gas chromatography/mass spectroscopy analyses of the oils tested were performed. The essential oils of Origanum vulgare, Satureja montana, Mentha piperita, Cinnamomum verum, Cymbopogon flexuosus showed maximum inhibitory activity (MIC = 500 ppm) after 7 days. According to the results of the examination of pure constituents, -phellandrene proved to be the most interesting component among cyclic monoterpenic hydrocarbons as it showed a strong activity (MIC = 50 ppm). The most active of phenols was carvacrol (MIC 100 ppm). The open-chain alcohol 1-decanol was the most active of alcohols at 50 ppm. Finally, among aldehydes, a strong activity was shown by trans-cynnamaldehyde (MIC 50 ppm).