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

Leaf essential oils of 11 samples from Ruta montana, Ruta chalepensis subsp. latifolia and Ruta chalepensis subsp. angustifolia collected from two sites have been studied by GC/MS that allowed to identify 22, 25 and 12 components, respectively. The variability in the composition of essential oils among species and seasons was very high, and hence the existence of different chemotypes has been inferred. The major components were 2-undecanone, (E) caryophyllene, 2-nonanone and 2-methyloctyl acetate. Multivariate analysis of the 11 samples suggest that the main factors capable to influence the chemical composition of leaf essential oils was both the collection period and the geographical origin. 2-Undecanone seems to be the chemotaxonomic marker of Ruta genus. Furthermore, the formation of distinct clusters and sub-clusters at high distance also supports that the patterns of distribution of chemical constituents among seasons can be used in delimiting species and infraspecific taxa within the species complexes.

ABSTRACTEugenia samanensis Alain is an endangered species of Myrtaceae unique to the Samaná Peninsula, Dominican Republic. We investigated its foliar essential oil (EO) composition from dried leaves, extracted via hydrodistillation, by gas chromatography-mass spectrometry (GC-MS) for identification and gas chromatography-flame ionization detection (GC-FID) for quantification. E. samanensis leaves produced an average of 1.6 ± 0.1% (w/w) EO and 23 compounds were identified, representing 98.4% of the EO composition. The EO composition consisted of 84.4% phenylpropenes, 8.9% oxygenated monoterpenes, 4.0% oxygenated sesquiterpenes, 0.4 % monoterpenes, 0.4% sesquiterpenes, and 0.25% other. The EO was richest in the phenylpropene, methyleugenol. The abundance of phenylpropenes in the EO of E. samanensis may be unique to Eugenia, suggesting the need for further research to elucidate the biological function of these compounds, to review the taxonomic status of this species, and to perform further studies to explain the high phenylpropene content of this species.

We have previously studied the chemical composition of essential oil (EO) from seeds of Anethum graveolens from Xinjiang Autonomous District in the PRC [1]. The component composition of essential oils is known to depend on the habitat. It seemed interesting to compare the composition and biological activity of EO from dill seeds growing in China and Uzbekistan. We used GC—MS to establish the structures of the isolated compounds. EO from seeds of A. graveolens (2007 harvest) that were collected in Tashkent Oblast was isolated by steam distillation in 4.2% yield. The chemical composition of the EO was studied using a Perkin—Elmer Turbo GC—MS. The component content of the oil was calculated using areas of GC peaks of total ion current without correlation coefficients. EO components were identified by comparing retention times and mass spectra of the component obtained in mass scanning mode and by using mass-spectral library data for standard oil components and pure compounds. A total of 22 chemical compounds was identified in EO of A. graveolens seeds growing in Uzbekistan. Table 1 lists the chemical composition of the EO. The principal EO components from dill seed growing in Uzbekistan were carvone (73.61%), limonene (14.69), cis-dihydrocarvone (5.87), diplaniol (1-allyl-2,5-dimethoxy-3,4-methylenedioxybenzene) (2.16), and 1,2-diethoxyethane (1.43%), which together made up 99.2% of the total EO component composition. The principal components of EO from dill seed growing in China were n-pentacosane (27.96%), dioctylester of 1,2-phenyldicarboxylic acid (25.10), octacosane (13.81), tricosane (9.14), and n-nonacosane (6.85%) [1]. A comparison of our data with that obtained earlier indicated that both the qualitative and quantitative composition of the principal EO components of A. graveolens growing in different geographic zones differed considerably. The high content in the studied EO of carvone, which is widely used as a growth inhibitor of bacteria [2-4] and certain fungi [5] and as a repellent [6] is noteworthy. Both S-(+)-carvone and R-(-)-carvone are used in the food industry to produce flavors [4] and in agriculture. For example, S-(+)-carvone is used in the Netherlands to prevent premature sprouting of potato tubers and tulip bulbs during storage [7, 8]. Carvone is an available and inexpensive reagent for organic synthesis in both enantiomeric forms. This makes it attractive for asymmetric synthesis of natural compounds [9]. Antimicrobial activity of EO fractions toward Candida albican and Staphylococcus aureus was estimated using the Barry method to determine the minimal inhibiting concentration (MIC) [10]. Growth of microorganisms decreased markedly upon addition of EO to nutrient medium. The experimental results are given below:

The present study aimed to analyze the chemical composition and fumigant toxicity of essential oils (EOs) isolated by hydrodistillation from Piper hancei Maxim. EOs extracted from the dry stems and leaves of P. hancei were analyzed by gas chromatography-mass spectrometry (GC-MS). The main compositions of the EOs were humulene (13.624 %), caryophyllene (13.319 %), nerolidol (12.507 %), naphthalene (8.525 %), ledol (6.694 %), caryophyllene oxide (6.404 %), and junenol (6.350 %). The fumigant toxicity of the EOs was tested in 7-14 day old adults of Tribolium castaneum. The LC50 of EOs and individual main compositions were calculated according to the mortality of insects at concentrations of 0, 16, 32, 64, 128, and 256 (μL/L air). The results showed that the EOs (LC50=322.52 (48 h) and 145.82 (72 h) (μL/L air)), caryophyllene (LC50=37.95 (48 h) and 26.53 (72 h) (μL/L air)), junenol (LC50=38.32 (48 h) and 20.33 (72 h) (μL/L air)), caryophyllene oxide (LC50=97.72 (48 h) and 65.22 (72 h) (μL/L air)), and humulene (LC50=104.50 (48 h) and 73.66 (72 h) (μL/L air)) have obvious fumigant activities against T. castaneum adults. The chemical composition of EOs from P. hancei was reported for the first time. The results indicated that the EOs of P. hancei had the potential to be developed as a natural insecticide for the control of T. castaneum adults.

This study aimed to investigate the seasonal variation in the chemical composition and antimicrobial activity of Achillea fragrantissima essential oil (EO). EO was collected at 10 days intervals, from May to July 2014, for a total of seven harvests. The EO was extracted from aerial parts by hydro-distillation for 3 hours. The antimicrobial activity was evaluated by well diffusion method against three bacterial species (Escherichia coli, Staphylococcus aureus and Bacillus subtilis and two fungal species (Candida albicans and Aspergillus niger). The chemical composition of EO was performed by gas chromatography-mass spectrometry (GC-MS). The activity of the essential oils against the tested bacteria and fungi varied depending on harvesting time of A. fragrantissima. In general, the highest activity of A. fragrantissima essential oils was against Gram-positive bacteria at T6 (the end of June). The chemical constituents of EO showed quantitative and qualitative variation of several specific chemical compounds, the ratio of identified compounds range between 92.29 and 95.88%, the major fluctuations in the composition of EO also revealed the presence of trans-sabinyl acetate (0.75-10.20%), α-terpineol (3.53-9.39%), trans-Menth-2-en-1-ol (6.5-13.34%), and β-thujone (11.34-22.11). In this study, the antimicrobial activity and the chemical composition of the EO extracted from A. fragrantissima were affected significantly by the time of collection. T6 period would be the best time to harvest A. fragrantissima plants to obtain EO with the highest antimicrobial activity. The chemical difference noted among seasons may explain the different in antimicrobial activity.

Thymus holosericeus Čelak. (Lamiaceae) is a taxonomically isolated and endangered local endemic thyme species which is geographically isolated in four Ionian Islands (West Greece). The present study investigated the essential oil (EO) composition, the ecological preferences, and their correlations in three T. holosericeus wild-growing populations from Zakynthos (ΤH-Z), Cephalonia (ΤH-C) and Lefkada (ΤH-L). The variations in essential oil yield and the composition of T. holosericeus populations were evaluated using hydrodistillation, GC/MS, TLC and NMR analysis. The climatic conditions of each sample were organized and analyzed in RStudio with the raster package and in SPSS with Pearson’s Canonical Correlation Analysis (CCA), respectively. The aerial parts of the plants varied in EO yields from 1.92 to 2.28% w/v. The analysis of EO constituents revealed noteworthy qualitative and quantitative inter-population variation. The composition of EOs revealed the presence of linalool (82.77%) and borneol (5.95%) as major compounds in ΤH-Z, while carvacrol (35.34%), geraniol (23.98%), linalool (14.37%), borneol (5.66%), thymol (4.27%) and p-cymene (4.08%) were the main compounds in ΤH-C and linalool (40.37%), geraniol (39.42%) and borneol (5.20%) were dominant components in ΤH-L. The results of the gas chromatography procedure have also been confirmed by 1H and 13C-NMR and TLC analysis. The ecological profile showed an average annual precipitation of 942 ± 18.33 mm and the temperature limits in which T. holosericeus seems to adapt to are 6.80± 1.08 °C 27.70 ± 0.70 °C. Regarding the examined samples, TH-C was adapted to the driest summer and coldest winter conditions, TH-Z was adapted to the lowest annual precipitation with the most complex climatic conditions, and TH-L was adapted to the highest summer temperatures with the lowest precipitation in the wettest period of the year. For each sampled population, the CCA identified the association of the samples’ EOs composition with the prevailing local environmental conditions.

Thuja (Thuja sutchuenensis Franch.) (family Cupressaceae) is a Chinese endemic plant once declared extinct in China. After being rediscovered in 1999, it attracted the attention of domestic scholars. This study aimed to investigate the extraction process and composition of the essential oil from thuja to provide a reference for further research. The main xylem of thuja collected from the Qinling‐Bashan mountains was used as the experimental material. The essential oil of thuja was extracted by the supercritical carbon dioxide fluid extraction (SFE‐CO2) process, and the composition of the essential oil was detected by gas chromatography‐mass spectrometry (GC‐MS). Extraction pressure, extraction temperature, and extraction dynamic time were the main factors influencing the extraction rate. The optimal conditions for the extraction include the following: maintaining the extraction pressure at 20 MPa, extracting for 60 min at 45 °C, and maintaining the CO2 flow rate at 1.5 L min–1 at 120 °C. Under the optimal extraction conditions, the oil extraction rates of three verification experiments were 18.87, 18.63, and 19.07%. The GC‐MS detected 136 components from the extracted thuja essential oil, and 75 components were identified. The main components of the essential oil were cis‐thujopsene (23.54%) and cedrol (13.08%). In this study, the optimal process for SFE‐CO2 of essential oil from the xylem of thuja was obtained. Under this optimized process, the average oil content was 18.86%.

Chemical variability in the essential oils from leaves of Syzygium jambos

The essential oil composition of medicinal and aromatic plants may be affected by several factors, such as physiological stages, genetics and agronomic practices. The objective of the current study was to evaluate German chamomile (Matricaria chamomile L.) essential oil content and composition changes during the day by harvesting the flowers at different time (8:00-10:00 am, 10:00-12:00 am, 12:00-14:00 pm, 14:00-16:00 pm, 16:00-18:00 pm and 18:00-20:00 pm, 121 days after seedling transplantation). For each sample essential oil was separately extracted by hydro-distillation and the fixed oil by extraction with hexane, then chemical composition of essential oil was analyzed by GC-MS. The essential oil percentage in chamomile flowers sampled at different time of the day were found as 0.812% for 8:00-10:00 am, 1.11% for 10:00-12:00 am, 0.952% for 12:00-14:00 pm, 0.806% for 14:00-16:00 pm, 0.908% for 16:00-18:00 pm and 0.652% for 18:00-20:00 pm. Harvesting between 10:00 and 12:00 pm showed the highest essential oil percentage (1.11 %), whereas flower collection between 18:00 and 20:00 pm indicated the minimum essential oil percentage (0.65%). The changes in essential oil phytochemical profile suggest the crucial effect of harvesting time on essential oil composition. The most abundant compounds were (E)-anethole, α-bisabolone oxide A and α- bisabolol oxide B in samples harvested in the morning and (E)-β-farnesene, α-bisabolol oxide A, occidol acetate and chamazulene in samples harvested at noon and in the afternoon. According to these results it can be deduced that if higher essential oil content is desired harvesting should be performed at noon and accomplished in one day.

Lippia origanoides H.B.K. essential oil production, composition, and antioxidant activity under organic and mineral fertilization: Effect of harvest moment

In order to investigate plant density and application rates of vermicompost on essential oil content and composition of Balm, the experiment was conducted during 6 months in Dineh phytomedic company in 2010. This experiment was carried out in complete randomized block design with 3 replications at three plant densities (6, 8 and 10 plant/m2) and four application rates of vermicompost (0, 5, 10 and 15 ton/ha). In floral imitation, plants harvested and essential oil were extracted by water distillation. The essential oils were analyzed by GC and GC/MS. The results showed a significant difference (%1) among plant densities and application rates of vermicompost on essential oil yield. maximum amount of essential oil obtained from 10 plant/m2 and 10 ton/ha vermicompost consumption. Identification of essential oil components showed that plant density had no effect on essential oil composition but some compounds of the oil decreased with more application of vermicompost, whereas some other compounds increased with most application of vermicompost.

The composition of essential oil from the leaves of Leucosidea sericea and the impact of drying methods (air, sun, oven and microwave) on yield, composition, antibacterial and antifungal activities of the oil was studied. A total of 7 compounds were identified from both the fresh and air dried leaves, while 37 and 13 compounds were identified from sun and oven dried leaves respectively. The essential oil from fresh leaves was dominated by monoterpenes with α-pinene as the dominant compound in both fresh and air dried leaves (95.82 and 96.27% respectively), but its percentage was significantly reduced in the oil obtained from oven dried leaves (58.66%) and it was not detected in sun dried leaves. Sun drying the leaves resulted in the highest number of compounds with dominant ones being by β-pinene (31.50%), limonene (9.82%), isopinocarveol (8.76%), p-menth-1-8-ol (7.03%) and α-thujone (7.00%). Microwave oven drying led to a total loss of volatile compounds, whereas sun drying the leaves lead to a significant change in the composition of the essential oil. The study showed that drying the leaves at higher temperatures (oven and microwave) led to a significant reduction in essential oil yield. Antibacterial activity of the oil showed remarkable activity against both Gram-positive and Gram-negative bacteria, as well as four fungal species used in the study. The antimicrobial activity of the essential oil can be attributed to the presence of major components such as α-pinene, β-pinene, and limonene.

Recently, a series of papers reported preparation and physicochemical properties of various kinds of water treated in contact with various gases with low-temperature, low-pressure glow plasma of low frequency (LPGP). Consecutive papers presented results of watering numerous herbal plants with those kinds of water in planting of numerous herbal plants. Always, the watering influenced the yield and quality of the crops and considerably changed the composition of the essential oils extracted from the watered plants. This paper provides the effects of watering of Cannabis sativum var. Finola with water LPGP-treated either in the air (LPGPA), under molecular nitrogen (LPGPN) or carbon dioxide (LPGPC). Cannabis sativa, particularly its botanic class called hemp, attracts great attention for its numerous applications. They include rope, textiles, clothing, shoes, food, paper, bioplastics, insulation, biofuel and industrial fibre. The watering was maintained for 12 weeks. Regardless of the kind of the used plasma-treated water, a considerable increase in the plant crop yield was noted for first 7 weeks. Further cultivation resulted in a minute increase in the yield. The watering with LPGPC offered the highest crop yield, followed by nontreated water, LPGPN and LPGPA. The yield of essential oil per 1 g of plant was independent of the used kind of plasma-treated water. Watering Finola with LPGPA resulted in a decrease in the level of cannabidivarin (CBD V) and considerable increase in the deal of Δ 9-tetrahydrocannabinol (Δ9-THC). The levels of the remaining components of the essential oil slightly decreased with respect to that in the control sample. Almost identical trends in the influence of watering upon the composition of essential oil were observed in the case of LPGPN. However, an unusually strong decrease in the level of CBD V accompanied by a very high increase in the level of Δ9-THC could be noted. The performed study provided strong evidence that watering seeds and plants of Finola with various kinds of the LPGP-treated water could modulate and even tailor the crop yield, functional properties of the plant and essential oils extracted from it. The composition of the essential oil isolated from the plant watered with LPGPN suggests its application as a substitute of medical marijuana (medical cannabis).

In the present study, the chemical composition of the essential oil from aerial parts of two populations of Paeonia mascula subsp. russoi, collected in Sicily, was evaluated by GC–MS. No previously phytochemical investigation has been reported for this subspecies. The main components of the essential oil of the population with pink flowers were salicylaldehyde (34.31%), nonanal (16.95%) and 2-hexenal (10.17%), whereas essential oil of the population with white flowers, was shown to be rich of myrtanal (14.14%), eugenol (14.02%) and salicylaldehyde (12.21%). Furthermore, a complete literature review, not present in literature, on the composition of the essential oils of all the other taxa of Paeonia, studied so far, was performed. PCA and HCA analyses of the composition of essential oils obtained from the aerial parts were also carried out.

Cymbopogon citratus (lemongrass) is an aromatic species whose essential oil is rich in citral, with industrial applications due to its lemon scent. The effects of environmental factors on the percentage and composition of essential oils are the main challenges in commercial cultivation. Various studies have indicated the positive effect of cytokinin on terpene production. The present work aimed to evaluate the effect of N6-benzylaminopurine (BAP) associated with light intensity on the production and composition of essential lemongrass oil. Plants were grown under field conditions (FIELD) and shade (SHADE). The study employed a 2x7 factorial scheme with two growing environments, seven BAP concentrations, and five replicates. After seven months of growth, a single application of the synthetic cytokinin BAP was performed at concentrations 0, 30, 60, 90, 120, 150, and 180 mg L-1. One week after the BAP application, plants were harvested and the essential oil was extracted in a Clevenger apparatus. The chemical composition of the essential oil of plants treated with 60, 120, and 180 mg L-1 of BAP was determined by Gas Chromatography (GC). The essential oil percentage was not affected by the treatments, showing 1.08% on average. On the other hand, the citral percentage was negatively influenced by BAP, and light intensity had no effects. In plants treated with 60 mg L-1 of BAP, citral percentage was 72%, on average, while in plants treated with 180 mg L-1, the mean percentage of citral was 33%.