Variation In Oil Composition Research Articles

Seasonal Study Chemical Profiles and Bioactivities of Hedychium coronarium J. Koenig Essential Oils: Nematicidal, Insecticidal, Phytotoxic, Antifungal Potentials, and Molecular Docking Insights.

Hedychium coronarium plant has attracted considerable attention from researchers due to its diverse phytochemical composition and potential therapeutic applications. The objective of this study was to evaluate the phytochemical profile and biological attributes of H. coronarium essential oils collected during different seasons in the Kumaun region of Uttarakhand. The essential oils were extracted from the rhizomes using hydrodistillation with a Clevenger-type apparatus yielding between 0.07% to 0.38% (w/w). The major compounds identified by GC-MS analysis exhibited seasonal variations and included 1,8-cineole (26.6-38.5%), coronarin E (11.9-18.8%), α-pinene (5.00-14.9%), α-terpineol (4.2-9.3%), (E)-β-caryophyllene (1.2-9.7%), and linalool (0.4-2.9%). To illustrate the variations in oil composition, visualization techniques such as heat map and PCA were employed. The essential oils demonstrated potential biological activity in all tests conducted. The molecular modeling study indicated that the potential mechanism may be associated with acetylcholinesterase. Consequently, this study contributes to the development of novel natural pesticides.

Theoretical and Experimental Determinations of the Hydrophilic–Lipophilic Balance (HLB) of Representative Oils and Lecithins

The hydrophilic–lipophilic balance (HLB) is a valuable parameter used to determine the relative hydrophobicity of a compound based on its chemical structure. This semi-empirical parameter has been instrumental in formulating oil-in-water and water-in-oil emulsions using well-characterized ingredients with known HLB values. However, recent trends toward the use of minimally processed “virgin” oils of therapeutic or nutritional value may render the reported “required HLB” values inaccurate. Minimally processed oils can contain numerous compounds at varying or unknown concentrations, rendering the HLB value incalculable. Factors such as regional source, growing season, and processing method contribute to the variability in oil composition. Furthermore, the solubilization of lipophilic bioactives in oils can significantly alter the HLB of the oil phase in a concentration-dependent manner. This complicates the formulation of emulsions, as the HLB values of both the oil phase and emulsifiers must be closely matched to achieve stable formulations. This study presents a simple and efficient experimental method to determine an HLB value of a complex ingredient without resorting to lengthy Design-of-Experiment (DoE) matrices and trial-and-error approaches. The optimal HLB of a formulation can be determined from a series of experiments in which two well-characterized surfactants of known HLB values are mixed at varying proportions with an unknown oil phase, where the HLB of the oil is considered to match the HLB value of the surfactants combined at the proportion at which nanoemulsions with the smallest, most stable oil droplets are formed. Similarly, when the HLB values of the oil phase and other contributing components are precisely known, the unknown HLB of a complex natural surfactant can be calculated. These calculations assist in formulating emulsions efficiently and effectively by ensuring optimal compatibility among all the components.

Compositional Grading and Reservoir Oil Composition Variation with Depth Experiment by PVTi Software with Lab Data

Heavier molecules tend to migrate towards the bottom of column. Gross assumptions in PVT experiment are that the system is in gravitational and diffusive equilibrium. Starting from an oil and moving up a column, the fluid will become lighter and tend towards a gas (condensate). Two types of grading are possible. The first one is of the fluid going from an oil to a gas with a distinct gas-oil contact at some unique depth. If this situation occurs, it will be predicted. The second one is the Fluid grading from an oil to a gas without a contact. This case corresponds to the critical temperature of a composition within the reservoir equalling the reservoir temperature. In compliance with compositional grading study, the API and some properties of the reservoir oil composition such as sulphur and CO2 contents vary with the reservoir depth. Most of the time the gas-oil contact (GOC) is named as the reservoir datum depth. In this paper, the study of compositional grading and reservoir oil composition variation with depth experiment by PVTi software with lab data has been achieved and some good conclusions have been gained.

Study on Oil Composition Variation and Its Influencing Factors during CO2 Huff-n-Puff in Tight Oil Reservoirs

With immense potential to enhance oil recovery, CO2 has been extensively used in the exploitation of unconventional tight oil reservoirs. Significant variations are observed to occur in the oil’s composition as well as in its physical properties after interacting with CO2. To explore the impacts of oil properties on CO2 extraction efficiency, two different types of crude oil (light oil and heavy oil) are used in CO2 huff-n-puff experiments. Moreover, numerical simulation is implemented to quantitatively inspect the impacts of different influencing factors including production time, reservoir pressure and reservoir temperature on physical properties as well as on the oil composition variation of the crude oil. The findings of the experiments demonstrate that, whether for the light oil sample or for the heavy oil sample, hydrocarbon distribution becomes lighter after interacting with CO2 compared with the original state. In addition, it is also discovered that the hydrocarbon distribution variation is more significant for the light oil sample. The findings of the numerical simulation suggest that production time, reservoir pressure and reservoir temperature have significant impacts on the produced oil composition and properties. The hydrocarbon distribution of the oil becomes lighter with the increasing of production time and formation pressure, while it becomes heavier with the increasing of reservoir temperature. At the very beginning of the oil production, the properties of the produced oil are worsened. Compared with the original state, the oil density and viscosity are 25.7% and 200% higher, respectively. It is suggested that viscosity reducers are added into the well to improve the oil properties in this period. With the continuing of the oil production, the oil properties are continuously promoted. At the end of the simulation time, the oil density and viscosity are 3.5% and 15.1% lower compared with the original oil, respectively. This paper has great significance for the implementation of CO2 huff-n-puff in tight oil reservoirs.

Antibacterial, Antioxidant and Cytotoxic Studies of the Essential Oil and Ethanol Extract of Aerial Parts of Artemisia rutifolia Steph.ex. Spreng

Mongolia is rich in medicinal plants. In recent years, interest in plant-derived food additives has grown. This study was aimed to evaluate antioxidant, cytotoxic activities of aerial parts ethanol extracts from Artemisia rutifolia Steph.ex Spreng grown in Mongolia. The essential oil composition variability of A.rutifolia Steph.ex Spreng aerial parts collected from three different slopes of Kharkhiraa mountain was assessed by gas chromatography mass spectrometry (GC/MS). Chromatographic analysis of A.rutifolia Steph.ex Spreng essential oils showed the predominance of monoterpene hydrocarbons represented mainly by santolina triene, β-myrcene. The antioxidant and cytotoxic activities of the essential oil and ethanol crude extracts were determined by using DPPH and MTT assays. The antioxidant activity of A.rutifolia Steph.ex Spreng ethanol extract is 2.12 times higher than the antioxidant activity of the essential oil. The essential oil of A.rutifolia Steph.ex Spreng with a concentration of 150 mg/ml or 3μg/disk inhibits the growth of S.enterica 9.3 ± 0.76 mm, B.subtillus 10.3 ± 0.58 mm, S.aureus 9.6 ± 1.5 mm and has a moderate bacterial activity. The results clearly showed that the essential oil presented satisfactory cytotoxic activity against two human tumor cell lines HepG2 (human liver cancer cell line); AGS (human stomach cancer cell line). Our work revealed that the ethanol extracts and essential oil of Artemisia ritifolia Steph.ex Spreng grown in Mongolia has potential as sources of new antioxidant, and cytotoxic compounds, respectively. Essential oil of A.rutifolia Steph.ex Spreng contains caryophylline-7.19% and caryophylline oxide-5.82%, so the essential oil at a dose of 25 mg/ ml inhibits the growth of human stomach cancer cell (AGS). The results of the study were certified by the utility model certificate of “Soap Fragrance Elixir” with the registration number 20-003068.

Post-harvest Storage and Distillation Time of Cymbopogon flexuosus (Nees ex Steud.) W. Watson Biomass Affects Essential Oil Content and Composition in the Western Himalaya

Lemongrass is an aromatic crop widely utilized in aroma and pharmaceutical industries because of its pharmacologic and clinical properties. The worldwide demand for natural products has also increased and made the products’ quality, efficacy, and safety a major concern. Appropriate post-harvest management and processing techniques can maintain the quality of the produce because improper handling significantly deteriorates the quality and contribute to economic losses. Thus, a study was conducted to analyze essential oil content and chemical constitution of lemongrass with two experiments: (1) post-harvest drying storage (0, 12, 24, 36, and 48 h) and (2) distillation time (DT: 30, 60, 120, 180, and 240 minutes), conducted during 2017-18. In the post-harvest drying storage experiment, an increase in drying resulted in gradual moisture content reduction with the lowest at 48 h. The highest essential oil content was achieved at 48 h post-harvest storage and 240 min (minutes) DT. The major constituent, i.e. citral (neral and geranial) attained the highest percentage (81.2 %) at the longer storage hours (36 h) and at 60 min DT. The degradation, rearrangement, and disappearance of constituents resulted in essential oil composition variation; post-harvest drying storage and DT can acquire essential oil with disparity and specific chemical profile.

Genetic architecture and key genes controlling the diversity of oil composition in rice grains

Rice grain oil is a valuable nutrient source. However, the genetic basis of oil biosynthesis in rice grains remains unclear. In this study, we performed a genome-wide association study on oil composition and oil concentration in a diverse panel of 533 cultivated rice accessions. High variation for 11 oil-related traits was observed, and the oil composition of rice grains showed differentiation among the subpopulations. We identified 46 loci that are significantly associated with grain oil concentration or composition, 16 of which were detected in three recombinant inbred line populations. Twenty-six candidate genes encoding enzymes involved in oil metabolism were identified from these 46 loci, four of which (PAL6, LIN6, MYR2, and ARA6) were found to contribute to natural variation in oil composition and to show differentiation among the subpopulations. Interestingly, population genetic analyses revealed that specific haplotypes of PAL6 and LIN6 have been selected in japonica rice. Based on these results, we propose a possible oil biosynthetic pathway in rice grains. Collectively, our results provide new insights into the genetic basis of oil biosynthesis in rice grains and can facilitate marker-based breeding of rice varieties with enhanced oil and grain quality.

Measurement and Quantification of Diffusion-Induced Compositional Variations in Absence of Convective Mixing at Reservoir Conditions

We present numerical and experimental investigation on the existence of diffusion-induced compositional variations in a reservoir fluid in the absence of convective mixing. New pressure-decay experimental data are presented for ethane in contact with stock tank oil, and the values of diffusivity and solubility parameters are obtained by using the one-dimensional transient diffusion model and integral-based regression method. We show the variation in oil composition through composition-height measurements at the end of the experiment. Finally, the diffusion model with estimated parameters is used to predict the compositional variations, where comparisons show excellent agreement with the measurements, validating the parameter estimation technique and quantifying the compositional variations in the oil phase caused by diffusion.

Investigation of Essential Oil Composition Variation with Age of Eucalyptus globulus Growing in Ethiopia

Various types of aromatic and medicinal plants are available in Ethiopia from which the essential oil can be extracted for different purpose. Eucalyptus plant is most common among them. Despite its availability the variation of essential oils of Eucalyptus globulus with ages, the chemical constituents of Eucalyptus globulus essential oil of Ankober origin has not previously been examined. Thus, the aim of this study is to assess the variation of essential oil with ages in Eucalyptus globulus tree grown at Ankober district, Ethiopia. Most part of Ankober is covered by Eucalyptus globulus, locally known as ‘Nech-Baharzaf’. Essential Eucalyptus leaves having different ages were collected and subjected to steam distillation to determine the quality and quantity of essential oil (main components of the oils). Eucalyptus globulus leaves aged 3, 5, 8, 12, 20, 35 and 100 were compared. All the leaves were collected from the same agro-ecological zone and in the same season to avoid oil content variation with climate change and agroecology. Chemical composition of the essential oils was analyzed by GC/MS and alpha-Pinene, dlimonene and cineol were the main constituents. The highest amount of eucalyptol (73.90%) presented in plant aged 100 years whereas alpha-Pinene (20.05%) and d-limonene (6.17%) detected in essential oil of plants aged three. The main constituent of the oil is cineole, ranging from 61.04%-73.90% which might suggest age variation has significant impact on essential oil content composition.

Influence of temperature field on rock and heavy components variation during in-situ combustion process

The temperature field generated during an in-situ combustion (ISC) process sees dramatic variation from 50 °C to over 700 °C. The division of the reservoir into different temperature regions during an ISC process induces different phase state transition and chemical reactions, resulting in serious heterogeneity in oil compositions and reaction products. Combustion tube experiments were conducted to investigate the propagation behavior of combustion front, combined with outlook color observation of down-hole rock samples, permeability measurements (N2) and organic residual analysis. Fourier transform infrared spectroscopy (FTIR) and gas chromatography–mass spectrometry (GC–MS) were used to characterize the organic materials extracted from the combustion zones. X-ray diffraction (XRD) was employed to investigate the variation of mineral components before and after the ISC process. The results indicated that most of calcite component in the down-hole rock sample was decomposed in combustion front regions within the highest temperature range of 550–650 °C. The color transfer from light grey to brick-red in the outlook color observation demonstrated that an even higher temperature can be achieved. Permeability measurement had shown that secondary diagenetic reaction involving clay triggered a significant permeability reduction during the ISC process. This study demonstrated that variation of oil compositions from different locations of formation can serve as a direct indicator to the occurrence of fire chamber enlargement.

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.

A Mechanistic Understanding of Asphaltenes Precipitation From Varying-Saturate-Concentration Perspectives

Summary Asphaltenes precipitation within reservoir pores or production flowlines can severely hamper the petroleum-extraction process. Although the effect of temperature and pressure on asphaltene deposition is well-known, the manner in which the variations in oil composition affect the asphaltenes-precipitation mechanism requires more clarity. This work investigates the effect of crude-oil compositional change on asphaltene stability. The impact of oil composition is analyzed by preparing pseudocomponents through blending the crude oil with their own saturates fractions. A systematic characterization of 11 different bitumen and crude-oil samples was carried out by density and viscosity measurements and the determination of the elemental composition and saturates, aromatics, resins, and asphaltenes (SARA) contents. Further analyses were conducted on the asphaltenes separated by use of n-pentane. The cluster size was determined by a particle-size analyzer, and the stability of asphaltenes was evaluated by zeta-potential. The molecular structure of SARA fractions and bulk crude-oil samples was analyzed by Fourier-transform infrared (FTIR) spectroscopy. Onset-of-asphaltenes-precipitation (OAP) tests on crude-oil samples were achieved by the addition of different solvents (n-pentane, n-heptane, and crude-oil saturates fraction). While the physical characterization studies could only provide weak relations between the density/viscosity and the asphaltene content of the bulk samples, it has been found that mainly the ratio of the heavy (resins + asphaltenes) to light (saturates +aromatics) fractions controls the viscosity and the °API value of the crude oils. As this ratio increases, the crude oil becomes more viscous and dense. Also, the asphaltene/resin ratio was found to be critical because of its impact on asphaltene stability, which was determined through zeta-potential measurements. The high asphaltene/resin ratios result in low asphaltene stability; however, this effect is surpassed by the higher aromatics fraction in the bulk oil. Asphaltene stability was further studied with OAP tests. The OAP-test results provide the behavior of asphaltenes after the interaction of bulk oil samples with normal saturated hydrocarbons; however, our study improves the OAP-test procedure by conducting OAP tests with crude oil's own saturates fractions. The interaction of saturates fraction with crude oil resulted in more asphaltenes precipitation compared with interaction of n-pentane and n-heptane. The FTIR analyses indicate the presence of impurities in saturates fractions, and these impurities are believed to cause higher asphaltenes precipitation as a result of the polar nature of the impurities.

Impact of natural convection and diffusion on variation of oil composition through a fractured model

The first step to study oil reservoirs is determination of reservoir fluid composition in both horizontal and vertical directions. In this research, fluid composition distribution is investigated as a result of diffusion and natural convection in a naturally fractured model. A two-component single phase fluid and a rectangular two-dimensional fractured oil reservoir with a known temperature profile are used in this study. MATLAB software is exploited to solve governing equations, numerically. According to results, thermal diffusion has the greatest impact on the variation of fluid composition, followed by pressure and molecular diffusions, respectively. Moreover, it is found out that even a small convection would change the fluid composition distribution, considerably. Fluids tend to flow through the fracture due to its high permeability; therefore, a counterclockwise convective cell would flow in the reservoir.

Patterns of fatty acid composition in seed oils of Cuphea, with new records from Brazil and Mexico

Herbaceous flowering plants of the genus Cuphea (Lythraceae) are noted for synthesizing significant amounts of medium-chain caprylic, capric, lauric, and myristic fatty acids (FAs) in the seed oils, with each species typically emphasizing one of several FAs. The genus is a prospective temperate source of oilseeds for fatty acids used in the manufacture of products as diverse as soaps, food, and biofuels, and it has become a model research system for the study of enzyme-mediated fatty acid synthesis. Seed oil FA composition for 44 species is reported here, including first records for 25 species from South America, primarily from Brazil. Nineteen species are re-analyzed to verify earlier results and expand information on variability in oil composition. An Appendix summarizes seed oil composition of 108 species classified in two subgenera and in 10 of 13 sections. Fifty percent are lauric-acid (C12:0) producers. In South America, the most common FA dominating Cuphea oils is lauric acid. In North America, a secondary center of speciation, seed oils are more diverse; lauric and capric acid (C10:0) are most common, but caprylic (C8:0), myristic (C14:0), linoleic (C18:2), and linolenic acid (18:3) predominate in some species. The dominant FA in the seed oil of each species remains constant throughout its range and in differing habitats, and varies within a species in percentage of total FAs 14–17%. Factors affecting variation are briefly examined. The evolutionary pattern of the major seed oil FAs is explored using data from 61 species mapped to a molecular-based phylogenetic tree. Three significant divergent events indicate that changes in seed oil composition were influential in the adaptive radiation and speciation of Cuphea. The basal dichotomy of the genus separates subg. Cuphea with linoleic acid (C18:2) as dominant FA from subg. Bracteolatae with myristic and lauric acids dominant. Evolution of the dominance of capric acid (C10:0) occurred following introduction of the genus into North America. Greatest diversity of seed oils appears in North America in the most derived clade in the genus, where FAs from caprylic acid (C8:0) to linolenic acid dominate among the species.

Organic geochemical evaluation of hydrocarbons in Lower Cretaceous Middle Minagish reservoir, Kuwait

Organic petrography and geochemical analyses of 72 core samples from the Minagish Formation revealed vertical variations in oil composition between four wells from the Burgan, Maqwa, Minagish and Umm-Gudair fields. The Burgan Field has a homogeneous oil column while variations in oil column were recognized between fields. The thickest heavy oil column, 46 m, was identified in Minagish Field. GC and GC-MS of the light and intermediate parts of the oil indicates a similar oil type, with a common oil pool in all of the oil fields. Thus, the variation in the nature and distribution of the heavy fractions of the oil in the Minagish reservoir is not be related to the source rock, expulsion and/or oil migration, but related to changes that occurred after or during oil accumulation in the reservoir.The methods and the results of this study are useful for planning drilling specially in reservoirs with heavy oil intervals such as the Minagish reservoir.

Essential oil composition variability among natural populations of Pinus mugo Turra in Kosovo.

Pinus mugo Turra, is a native pine species in central and southern Europe, growing in high mountains area (altitudes 1.800–2.300 m.a.s.l.). In Kosovo, it is one of the native pines too, distributed in high altitudes in the Sharri Mountains and Albanian Alps Mountains. Its populations represent an important wealth of essential oil resources available, which make this species very important in terms of economic values. The chemical composition and yields of the essential oils of dwarf pine (Pinus mugo Turra) needles, twigs and cones from six wild populations in Kosovo were investigated with the aim to assess their natural variability. The identity of P. mugo was confirmed by morphology and DNA barcoding. Sixty-two compounds were identified representing 69–95 % of the total identified compounds. The yield ranged from 0.3–0.8 % v/w in needles, 1.0–2.4 % v/w in twigs and 0.1–0.5 % v/w in cones, depending on the origin of plant material and plant organs. α-Pinene (needles: 16.9–24.5 %; twigs: 4.5–8.8 %; cones: 3.1–5.6 %), β-pinene (needles: 1.5–5.4 %; twigs: 2.2–15.4 %; cones: 1.3–14.2 %), δ-3-carene (needles: 15.4–27.8 %; twigs: 24.0–51.6 %; cones: 10.5–31.5 %), limonene + β-phellandrene (needles: 1.9–5.9 %; twigs: 12.6–24.2 %; cones: 2.1–9.3 %), (E)-caryophyllene (needles: 4.4–8.9 %; twigs: 4.0–10.8 %; cones: 10.3–26.9 %) and germacrene D (needles: 4.0–8.3 %; twigs: 0.2–6.19 %; cones: 0.1–12.4 %) were the major components of the essential oil. Principal component analysis (PCA) and hierarchical cluster analyses (HCA) suggests that the population of P. mugo clustering is not related to their geographic location, but rather seemed to be linked to local selective forces acting on chemotype diversity. Low variability related to their geographic location has an economic importance since samples originating from different locations in Kosovo can treated with same standards.

Chemical and biocidal characterization of two cultivated Artemisia absinthium populations with different domestication levels

The objective of this study was the characterization and valorization of the essential oil from a domesticated Artemisia absinthium population (Teruel, Spain), and its comparison with another one (Sierra Nevada, Spain) undergoing the domestication process. These populations are being experimentally cultivated in the same field since 2008. We studied their biomass and essential oil production (Clevenger hydrodistillation, HD and semi-industrial vapor-pressure, VP). The domesticated population showed lower chemical variation and higher biomass and essential oil yields, allowing for the registration of a new plant variety. The observed variations in oil composition (HD, VP) between the two populations were mostly quantitative. The oils were characterized by the presence of cis-epoxyocimene, (−)-cis-chrysanthenol, chrysanthenyl acetate, linalool and trans-caryophyllene. The insect antifeedant (Leptinotarsa decemlineata, Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi) and antifungal (Fusarium spp. and Botrytis cinerea) effects of their oils were also tested. All VP extracts showed strong antifungal effects and the active antifungal compounds have been identified.

Chemical Composition and Antioxidant and Antimicrobial Activities of Wormwood (Artemisia absinthiumL.) Essential Oils and Phenolics

The aim of this study was to determine the chemical variability of wormwood extracts as affected by the growing region. Antioxidant and antimicrobial activities were also investigated. The essential oil composition variability ofA. absinthiumL. aerial parts collected from four different Tunisian regions was assessed by gas chromatography (GC/FID) and by gas chromatography mass spectrometry (GC/MS). In addition, total polyphenols, flavonoids, and condensed tannins as well as antioxidant, antibacterial, and antifungal activities of methanolic extract and essential oils were undertaken. Chromatographic analysis of wormwood essential oils showed the predominance of monoterpene hydrocarbons represented mainly by chamazulene. RP-HPLC analysis of wormwood methanolic extract revealed the predominance of phenolic acids. Antiradical activity was region-dependant and the methanolic extract of Bou Salem region has the strongest activity (CI50=9.38±0.82 µg/mL). Concerning the reducing power, the methanolic extract of Bou Salem, Jérissa, and Boukornine regions was more active than the positive control. Obtained results of antimicrobial activities showed that wormwood essential oil is endowed with important antibacterial activity which was strongly related to the organoleptic quality of oil which appeared strongly region-dependant.A. absinthiumL. EOs investigated are quite interesting from a pharmaceutical standpoint because of their biological activities.

Variation in antibacterial activity and chemical compositions of essential oil from different populations of myrtle

Myrtle (Myrtus communis L.) belonging to the family Myrtaceae, is an evergreen shrub that grows mainly in Mediterranean climates. In Iran, the plant grows in the Zagros Mountainous Range of the country. The essential oils from the leaves and fruits of the plant are widely used to enhance the flavor of foods, and cosmetic and pharmaceutical industries. In this study, essential oil was extracted from the leaves of M. communis collected from six natural habitats in three provinces (Ilam, Lorestan, and Kermanshah), Western Iran. The hydrodistillated essential oil was analyzed by GC/MS. Results indicated that there were significant differences (p≤0.05) among the various populations for the main constituents in the essential oils. The major components of the essential oils from different populations of M. communis were α-pinene (24.42–31.57%), limonene (trace to 23.55%), 1,8-cineole (5.92–21.21%), and linalool (8.72–11.56%). Results of the antibacterial activity in vitro indicated that the essential oils from M. communis have good inhibitory activities against bacteria, especially Staphylococcus aureus (PTCC 1112). Results obtained in this study revealed that there is a high potential of the essential oil composition variability among the populations of myrtle. The results can be used in selection programs for production of aromatic myrtle with suppressing effects on pathogens.

Volatiles of Geranium purpureumVill. and Geranium phaeum L.: Chemotaxonomy of Balkan Geranium and Erodium Species (Geraniaceae)

The essential oils obtained by hydrodistillation of Geranium purpureum and G. phaeum were characterized by GC-FID and GC/MS analyses (the former for the first time in general). In total, 154 constituents were identified, accounting for 89.0-95.8% of the detected GC peak areas. The investigated essential oils consisted mainly of fatty acids and fatty-acid-derived compounds (45.4-81.3%), with hexadecanoic acid and (E)-phytol as the major components. The chemotaxonomic significance of the variations in the essential-oil composition/production of the presently and previously investigated Geranium and highly related Erodium taxa from Serbia and Macedonia was assessed by multivariate statistical analyses. The main conclusions drawn from the high chemical similarity of the two genera, visible from the obtained dendrograms and biplots, confirm the close phylogenetic relationship between the investigated Geranium and Erodium taxa, i.e., that there is no great intergeneric oil-composition variability. Changes in the composition and production of essential oils of the herein investigated taxa and 60 other randomly chosen species belonging to different plant genera were also statistically analyzed. The results put forward pro arguments for the oil-yield-oil-composition correlation hypothesis.