Oil Components Research Articles

Use of machine learning methods in predicting the main components of essential oils: Laurus nobilis L.

Laurus nobilis L. is an export plant that contributes to the industry with its medicinal and aromatic properties, as well as the use of its leaves or fruits in the food, pharmaceutical, and cosmetic industries. This study aims to predict the first three main components of bay laurel essential oil with different machine learning methods as a result of GC-MS analysis, taking into account a wide range of parameters used before and after the analysis of the essential oil in pharmacognostic studies. In this study, the K-Means algorithm was used to detect unknown relationships (chemical or physical properties) between the data obtained as a result of the analysis, and Artificial Neural Network (ANN) and Decision Tree machine learning methods were used to perform prediction operations. Based on this, considering the R2 values obtained from ANN analyses, R2 values of 0.9992 for testing, 1 for training, 1 for validation value, and 0.99992 for all were obtained. The ANN model produced results close to the real values with an accuracy rate of 98.97% in predicting the three main components. The Decision Tree algorithm achieved classification with a 96.23% accuracy rate in predicting the three main components. K-Means clustering was performed with an accuracy rate of 97.83% and significant relationships between the features of the Laurus nobilis dataset were detected. This comprehensive study serves as a guide for machine learning research on other essential oils.

Effectiveness of Essential Oil Component Cocrystals Against Food Spoilage Bacteria

AbstractImproving food preservation technologies is a key aspect in the struggle to reduce global food waste, and natural antimicrobial substances, such as essential oil (EO) components represent very promising food preserving agent. However, their intrinsic chemico‐physical properties, such as the low melting point, low water solubility and high volatility, pose some practical difficulties in exploiting them for practical applications. Cocrystallization is used to stabilize liquid or volatile EO components providing them whit a crystalline environment, thus improving their potential application as antibacterial agents. Five EO active ingredients (THY = thymol, CAR = carvacrol, EUG = eugenol, CAD = trans‐cinnamaldehyde, and VAN = o‐vanillin) and two coformers (INA = Isonicotinamide, and HBA = 4‐hydroxybenzoic acid) have been combined and the corresponding cocrystals have been studied for their potential inhibiting effect against four food spoilage bacteria (Bacillus thuringiensis, Enterobacter cloacae, Pseudomonas fluorescens, and Serratia marcescens). The structures of the five cocrystals have been used to derive structure‐activity relationships in terms of release energy of the active ingredients form the crystalline environment, and a correlation has been derived with the Intermolecular Interaction Energies of the EO molecules.

Parentucellia viscosa (growing in Türkiye): Essential Oil, Phenolic Composition, Antimicrobial and Lipase Inhibition

The essential oil (EO) and phenolic constituents of Parentucellia viscosa L. were analyzed by GC-FID-MS and HPLC, respectively. A total of 20 volatile compounds were identified accounting for 99.97% in hydrodistillation. Monoterpenes (50.57%, 5 compounds) were the primary chemical class in the essential oil of P. viscosa. Limonene (44.02%) and 1-octen-3-ol (25.23%) were the major components in the essential oil of P. viscosa. The phenolic constituent analysis for the methanol extract of P. viscosa gave benzoic acid (0.97 mg/g) as the major compound. The antimicrobial activities of the EO and crude solvent (n-hexane, acetonitrile, methanol, and water) extracts of P. viscosa were screened in vitro against ten microorganisms. n-Hexane and the acetonitrile extracts of P. viscosa resulted in the best activity against Mycobacterium smegmatis with IC50 values of 19.2 µg/mL and 53.8 µg/mL, respectively. The highest lipase enzyme inhibition activity was detected in the n-hexane extract with 44.22±1.1628 µg/mL IC50 value.

Chemical characterization and biological potentials of the essential oil from the peel of the fruit of Citrus x sp

Considering the importance of essential oils, the study aimed to chemically characterize the peel essential oil of Citrus x sp, determine the phenolic compounds, verify the toxicity against Artemia salina, and test the anti-inflammatory, larvicides, and activities with molluscicides. The peel essential oil of Citrus x sp was extracted by the hydrodistillation technique. GC/MS shows that the major component of the essential oil is limonene (70.25%), observing similarity between the peel essential oil of the same species and between species of the same genus. The total phenolic was 19,25 EAT g-1. The essential oil showed anti-inflammatory, larvicide, and molluscicide potential, with EC50 = 400.05 mg L-1, LC50 = 20.26 μg mL-1 and LC90 = 87,50 μg mL-1, respectively. It did not show toxicity against Artemia salina. The results indicate that the chemical compounds of the peel essential oil of Citrus x sp, which are mostly monoterpenes, prove their wide biological activity, and their use is encouraged.

Antimicrobial activity of essential oil components against Escherichia coli depends on the food components present in a food matrix

Despite numerous studies evaluating the antimicrobial activity of essential oil components (EOCs) against different microorganisms, the effect of the composition of the matrix in which they are applied remains unexplored. Hence, the effect of different food components (i.e., proteins, lipids, carbohydrates, acids, ethanol) on vanillin antimicrobial activity was carried out by assessing the growth of E. coli at different incubation times (0, 1, 4, 8 and 24 h). Based on these outcomes, the food components that most adversely affected vanillin antimicrobial activity were subsequently tested with four other EOCs (i.e., carvacrol, eugenol, geraniol, thymol). The effective concentration of antimicrobials after coming into contact with food components was quantified. The results indicated that bovine serum albumin (BSA), sunflower oil and carbohydrates partially or completely inhibited the antimicrobial efficacy of the tested EOCs, and the inhibition rate depended on the specific EOC-food component combination. Geraniol was notably the most efficient with BSA present. Eugenol performed best with sunflower oil. Carvacrol, eugenol, geraniol and thymol were more effective than vanillin with D-lactose present. This study confirmed that loss of EOCs’ effective concentration due to an interaction with food constituents is a significant cause of antimicrobial activity inhibition. These findings underscore the importance of considering matrix composition when selecting antimicrobials to combat a particular strain in real food applications.

γ-oryzanol ameliorates the oxidative stress and inflammatory response in a mice model of LPS-induced liver injury

Background: γ-Oryzanol (ORY) is a main component of rice bran oil and consists of a mixture of phytosteryl ferulates with antioxidant and anti-inflammatory properties. The purpose of this study was to evaluate the protective effects of ORY on hepatic oxidative damage and inflammatory response induced by lipopolysaccharide (LPS) in adult male mice. Materials and Methods: Adult male BALB/c mice (n=24) were intraperitoneally administered either LPS (0.75 mg/kg/d) or saline for a week. Meanwhile, mice were supplemented with ORY (100 mg/kg/d, gavage) or vehicle for 2 weeks. After treatment, animals were sacrificed and the markers of liver injury including aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were evaluated in blood. In addition, we measured the oxidative stress and inflammatory markers including lipid peroxidation (TBARS), total free thiol, catalase activity, tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), interleukin 6 (IL-6), and nuclear factor kappa B (NF-κB) expression levels in hepatic tissue. Results: Systemic LPS injections induced oxidative stress in the liver of treated animals, characterized by increased TBARS, with significantly decreased catalase activity and total free thiol content. Besides, the serum levels of ALT and AST increased in all experimental groups compared with the control group. These findings were accompanied by the increased hepatic expression levels of IL-6, IL-1β, TNF-α, and NF-κB. Furthermore, pathological evaluation of tissues showed LPS-induced microvesicular steatosis, which was ameliorated by ORY supplementation for two weeks. Conclusion: In summary, our results demonstrate that LPS-induced hepatic damage is mitigated by ORY supplementation in adult mice. These findings support the idea that natural products can protect against hepatotoxicity.

Apoptosis of Pancreatic Cancer Cells after Co-Treatment with Eugenol and Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand.

Pancreatic cancer is a refractory cancer with limited treatment options. Various cancer types are resistant to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Eugenol, the main component of clove oil, exhibits anticancer, anti-inflammatory, and antioxidant effects. However, no studies have reported that eugenol increases TRAIL sensitivity by upregulating death receptor (DR) expression. Here, we aimed to investigate eugenol as a potent TRAIL sensitizer. Increased apoptosis and inhibition of cell proliferation was observed in pancreatic cancer cells treated with eugenol and TRAIL compared with those treated with eugenol alone. Eugenol upregulated the expression of DR5, inhibited the FLICE-inhibitory protein (FLIP), an anti-apoptotic protein, and increased p53, a tumor suppressor protein. In addition, eugenol induced the generation of reactive oxygen species (ROS) and caused endoplasmic reticulum (ER) stress. C/EBP-homologous protein (CHOP) knockdown using siRNA decreased the expression of DR5 and reduced the combined effects of eugenol and TRAIL. These results demonstrate that eugenol enhances TRAIL-induced apoptosis by upregulating DR5 through the ROS-mediated ER stress-CHOP pathway, which enhances ER stress by inducing p53 and downregulating FLIP expression. This suggests that eugenol has the potential to treat pancreatic cancer by increasing cell sensitivity to TRAIL.

Palm Oil (Elaeis guineensis): A Journey through Sustainability, Processing, and Utilization.

Palm oil, derived from Elaeis guineensis, is a critical component of the global edible oil and industrial fat market. This review provides a comprehensive overview of the sustainability of the palm oil chain, focusing on industrial applications, environmental implications, and economic sustainability. The processing of palm oil, from fruit pulp to refined oil, is detailed, highlighting the importance of refining in maintaining quality and extending application ranges. While palm oil offers health benefits because of its rich fatty acid composition and antioxidant properties, its production poses significant environmental challenges. This review underscores ongoing efforts to balance technological and culinary demands with environmental stewardship and sustainable economic growth. Emerging trends, including interspecific hybrids such as E. guineensis and E. oleifera, are discussed for their potential to increase sustainability and productivity.

Global feature capture and spatially-aware neural networks for predicting CO2-flooding performance in heterogeneous low-permeable reservoirs

CO2-flooding can enhance crude oil recovery rates by reducing the viscosity of crude oil, improving the mobility ratio between crude oil and water, and leveraging the swelling effects of crude oil components. Furthermore, it facilitates the sequestration of greenhouse gases, leading to the realization of carbon capture, utilization, and storage (CCUS), which holds significant strategic importance for mitigating climate change, safeguarding ecological environments, and achieving sustainable development. Consequently, predicting CO2-flooding performance in heterogeneous low-permeability reservoirs holds crucial significance in sustainable energy production. However, the drawbacks of numerical simulation techniques, such as extensive computational resource consumption and prolonged simulation durations, have prompted extensive research into the utilization of artificial intelligence technologies. Prevalent approaches often treat the problem as a time series issue, which proves inadequate for reservoirs lacking historical production data. Furthermore, this methodology is unable to fully exploit the complex implicit relationships between various factors and the prediction target. Our study proposes a novel method for predicting the performance, which stands apart from previous approaches by not treating the problem as a time series issue, eliminating the need for historical production data for each prediction, and can predict various production variables such as gas production, oil production, water production, etc. in a universal manner. We combine enhanced MultiScale Non-local Neural Networks with ConvNet to handle sparse well network matrices with injection-production parameters. Additionally, we employ MultiScale convolutional networks with spatial attention mechanism to address formation permeability fields with spatial distribution features. Experimental results demonstrate the superiority of our approach in accuracy, achieving a prediction accuracy of over 97%. This research provides an innovative and flexible method, making significant contributions to the intelligentization and sustainable development of the petroleum industry, aligned with global efforts to both reduce carbon emissions and neutralize the existing ones.

Phytochemical Characterization of the Aerial Parts of Teucrium nuchense K. Koch: An Endemic Species of Caucasian Flora

Background: The genus Teucrium L. is frequently employed in traditional medicine, primarily for addressing disorders of the digestive and respiratory systems. Biological investigations focused on essential oils have substantiated their antibacterial, antioxidant, anti-tumor, anti-diabetic, and anti-rheumatic properties. Objective: The aim of the study was to assess the chemical composition and biological activities of the aerial parts of the endemic species Teucrium nuchense K. Koch. Methods: The chemical composition of the essential oil was analyzed using gas chromatography-mass spectrometry (GC-MS). The antioxidant activity was evaluated through the Oxygen Radical Absorbance Capacity (ORAC) assay and tested on normal skin fibroblasts (WS-1). Additionally, the antiinflammatory efficacy was assessed by monitoring nitric oxide production. The total phenolic content in the aqueous, methanolic, and chloroformic extracts was quantified using the Folin-Ciocalteu reagent. Individual compounds were isolated using preparative high-performance liquid chromatography. Their identification was accomplished using high-resolution mass spectrometry (HRMS) with an ESI-Q-TOF detector in conjunction with nuclear magnetic resonance (NMR) spectroscopy. Results: The essential oil yield was 0.32 ml/kg. Caryophyllene oxide, constituting 15.19 %, and 1- octen-3-ol, constituting 8.75%, emerged as the primary components in the essential oil. Oxygenated sesquiterpenes dominated the terpenic compounds, representing 25.1 % of the essential oil. The aqueous and methanolic extracts displayed a notable phenolic content, with percentages of 27 ± 2 % and 35 ± 0.1 %, respectively. Both the aqueous and methanolic extracts demonstrated robust antioxidant activity in the ORAC test and in vitro assessments using WS-1 cells. The methanolic extract, at a concentration of 160 μg/ml, inhibited NO formation by 90 %, without toxicity in RAW 264.7. Individual compounds, teucrioside from the phenylethanoid glycoside class, two neo-clerodane diterpenes, teucrin A, and 6-alpha-hydroxyteuscordine, were isolated. Conclusion: The essential oil extracted from the aerial parts of Teucrium nuchense is characterized by the presence of caryophyllene oxide and 1-octen-3-ol. The methanolic extract exhibits notable antioxidant as well as anti-inflammatory properties, whereas the aqueous extract demonstrates high antioxidant activity. Additionally, three compounds of teucrioside, teucrin A, and 6-α- hydroxyteuscordine have been isolated and characterized.

Simulation of extractive distillation of C6 components from Fischer‐Tropsch Synthesis oil

AbstractExtractive distillation is used for separating oxygenates from other components in the C6 cut oil from Fischer‐Tropsch Synthesis followed by separating 1‐hexene from N‐hexane using the same solvent as the extractant. Furfural (FUR) is identified as an excellent solvent for extractive distillation of the C6 cut from FTS oil for separating oxygenates from other components as well as for separating 1‐hexene from N‐hexane via searching from more than 100 solvents by simulation using Aspen Plus. The behavior of the newly found solvent FUR is compared with that of the reported best solvent N‐methyl‐2‐pyrrolidone (NMP) and the results show that FUR scheme has the advantages of lower market price, lower dosage needed, less reboiler duty required and higher overall tray efficiency for fulfilling the same separation task.

Study of Eucalyptus pauciflora L. characteristics from Algeria and its impact on the mite affecting honeybees Apis mellifera

Essential oils play a crucial role in biological control against parasites threatening the beekeeping stock, both in Algeria and globally. Their appropriate use helps reduce the adverse effects of chemical products on human health and the environment. The purpose of this study is to analyze the components of Eucalyptus pauciflora essential oil grown in Algeria and to evaluate its impact on the marine shrimp Artemia salina and the mite Varroa destructor, while also comparing it to other species of Eucalyptus from the same region namely, Eucalyptus robusta, globulus, sideroxylon, and amygdalina, which have been examine in previous research. Steam distillation of fresh leaves from Eucalyptus pauciflora yielded 0.73% essential oils. This plant contains a total of thirty-nine chemical compounds, among which the most significant are 1,8-cineole (57.45%), β-cymene (5.44%), spathulenol (5.38%), trans-verbenol (4.31%), and α-pinene (3.11%). A lethality test on brine shrimp (BSL) revealed that Eucalyptus pauciflora exhibits toxicity with a median lethal concentration (LC50) of 53.51 ppm. Field trials conducted on hives infested with Varroa destructor showed that the acaricidal effect of Eucalyptus pauciflora is superior to that of amygdalina and sideroxylon species, but inferior to that of globulus and robusta species, all sourced from the same herbarium (Draa Naga) in northeastern Algeria. The results of this research highlight the benefits of Eucalyptus essential oils to be integrated into the formulation of natural acaricides that are environmentally friendly to combat Varroa destructor infestation.

Evaluation of Essential Oil Components in Genetically Modified Poaceae Plants: A Comparative Study of Their Whitening and Antioxidant Activities In Vitro

Evaluation of Essential Oil Components in Genetically Modified Poaceae Plants: A Comparative Study of Their Whitening and Antioxidant Activities In Vitro

Sanguisorba officinalis L. ethanolic extracts and essential oil - chemical composition, antioxidant potential, antibacterial activity, and ex vivo skin permeation study.

Sanguisorba officinalis L. is classified as a medicinal plant and used in traditional medicine. The root of this plant is mainly used as a medicinal raw material, but the above-ground parts are also a valuable source of health-promoting biologically active compounds. The study aimed to evaluate the antioxidant activity and total polyphenol content (TPC) of extracts prepared in 70% and 40% aqueous ethanol solution (dry extract content 50-500g/L) from the aerial parts of S. officinalis. The essential oil was isolated from the tested raw material, and its composition was determined using GC-MS. Ethanolic extracts and essential oil have been tested for antibacterial activity. The extract in 70% v/v ethanol (dry extract content: 500g/L) was subjected to HPLC analysis for the content of selected phenolic acids and an ex vivo skin permeation study. The ability of these metabolites to permeate and accumulate in the skin was analysed. Extracts prepared at both ethanol concentrations showed similar antioxidant activity and TPC. Depending on the method, concentration of solvent, and dry extract content (50-500g/L), the activity ranged from 1.97 to 84.54g Trolox/L. TPC range of 3.80-37.04gGA/L. Gallic acid (424mg/L) and vanillic acid (270mg/L) had the highest concentrations among the phenolic acids analysed. Vanillic acid (10μg) permeates the skin at the highest concentration. The highest accumulation in the skin was found for 2,5-dihydroxybenzoic acid (53μg/g skin), 2,3-dihydroxybenzoic acid (45μg/g skin), and gallic acid (45μg/g skin). The tested ethanolic extracts exhibited antibacterial activity. Samples with a dry extract concentration of 500g/L showed the largest growth inhibition zones. The most sensitive strains to these extracts were P. aeruginosa (24mm), S. lutea (23mm), and S. pneumoniae (22mm). The smallest inhibition zones were observed for B. subtilis (17mm). The essential oil showed weaker antimicrobial activity (growth inhibition zone 8-10mm). The GC-MS method identified 22 major components of the essential oil, including aliphatic hydrocarbons, unsaturated terpene alcohols, aliphatic aldehydes, unsaturated and saturated fatty acids, sesquiterpene, phytyl ester of linoleic acid, nitrogen compound, phytosterol, terpene ketone, phenylpropanoids, aliphatic alcohol, diterpenoid, aromatic aldehyde, and aliphatic carboxylic acid. The conducted research has shown that ethanolic extracts from Sanguisorbae herba are a valuable source of compounds with antibacterial and antioxidant potential, including phenolic acids. The fact that selected phenolic acids contained in the tested extract have the ability to permeate and accumulate in the skin provides the basis for conducting extended research on the use of extracts from this plant raw material in cosmetic and pharmaceutical preparations applied to the skin.

Simultaneous quantification of the main components of Thymus vulgaris essential oil in edible coating formed from nanocapsules using HS-SPME-GC-FID

AbstractThe use of edible coatings (ECs) containing essential oils (EOs), such as that derived from the Thymus vulgaris plant (EO-Tv), offers a natural option for preserving and increasing the shelf life of fruit and vegetable products. However, considering their physicochemical properties, the incorporation of EOs into nanocapsules (NCs) represents an alternative to reduce their volatility and oxidation. In this way, quantitative determination of the EOs incorporated into NCs is necessary for simultaneous monitoring of their main components during the nanoencapsulation process, as well as for the future precise and accurate dosage of EO components in fruit and vegetable products. In this study, ECs were formed from NCs loaded with EO-Tv and sodium alginate (AL). The EO-Tv was characterized through GC-MS and GC-FID analysis, and it was found that the major component of EO-Tv was thymol, with an abundance of 30.91%. Subsequently, an analytical method based on HS-SPME-GC-FID was developed and validated for quantification of the EO-Tv encapsulated in NCs and incorporated into the EC. The method was found to be precise and accurate for quantification of the main components of EO-Tv in the formed EC. Once the analytical method was validated, it was established that the encapsulation efficiency was greater than 50% in the case of NC-EO-Tv purified via evaporation at reduced pressure. On the other hand, 35.78 μg cm−2 of thymol was quantified in the EC formed from the NCs and AL. The present work presents an analytical tool for simultaneous quantification of the main components of EO-Tv in NCs, as well as in the ECs formed with NCs, promoting its potential application in fruit and vegetable products.

Larvicidal activity and chemical composition of essential oils against Aedes aegypti Linn (Diptera: Culicidae) and Aedes albopictus Skuse (Diptera: Culicidae)

Introduction Aedes mosquitoes are the main vectors of the dengue, chikungunya, and Zika viruses. Essential oils have been used in research as alternatives to the synthetic insecticides traditionally used in programs to control these diseases. Methods: leaves of plants from the Caatinga biome were used to obtain essential oils which were used for larvicide essays against Aedes aegypti and Aedes albopictus larvae. Results: significant differences were observed in the LC50 values of C. zeylanicum, C. winterianus, E. citriodora, O. micranthum, and T. erecta essential oils in Ae. aegypti, while these differences were observed for A. conyzoides, C. winterianus, E. citriodora, and O. micranthum essential oils in Ae. albopictus, at the analyzed times. The LC50 for 24 h revealed a significant larvicidal effect for all tested samples, with emphasis on the effect of A. conyzoides and L. gracilis essential oils on Ae. aegypti, and the effect of A. conyzoides, C. zeylanicum, C. winterianus, L. gracilis, and O. micranthum essential oils on Ae. albopictus, all with an LC50 < 100 ppm. It was observed a predominance of terpenes as components in the essential oils, and, in some of them, representing the major constituent (citronellal: 47.71% in E. citriodora and 47.63% in C. winterianus; geraniol: 30.54% in C. winterianus; citronellol: 25.61% in E. citriodora; carvacrol: 55.13% in L. gracilis; and cyclohexen-1-one, 2-isopropyl-5-methyl-: 69.94% in T. erecta). The other major compounds observed were precocene (chromene - 97.66% - A. conyzoides), and eugenol (phenylpropanoid - 96.28% and 73.21% - C. zeylanicum and O. micranthum, respectively). Conclusions: the findings of this study revealed the larvicidal potential of these essential oils on Ae. aegypti and Ae. albopictus control, representing an alternative source to the traditional chemical controls used against the populations of these vectors. Further studies on the effects on non-target organisms and the combined action of two or more essential oils evaluated under field conditions are essential for obtaining commercially efficient formulations of these extracts.

Study of the toxicity of the essential oil of Brocchia cinerea

Brocchia cinerea is a North African plant belonging to the Asteraceae family, widely utilized in Algerian folk medicine to treat a variety of illnesses. These therapeutic virtues are mainly due to the plant essential oil. The chemical components of this oil were identified using GC-MS, and the variability in these components' levels was examined in nine samples that were taken at different times from two locations in Algeria's northern Sahara. The contents of the essential oil were found to consist of eight components, varying in concentrations: beta-thujone (46.80%), 1-Methyl-2-(1' methylethenyl) -3'- ethenylcyclopropylmethanol (14.59%), 1,8-Cineole (12.63%), limonen-10-ol (9.47%), 1(7),3,8 o Menthatriene (3.45%), and (-)-Camphor (2.11%). Toxicity studies were conducted in order to assess the safety of the essential oil, namely: LD50 estimation and biochemical blood parameters evaluation. The results showed an LD 50 of 507.5mg/kg close to the LD50 of Beta-thujone (442mg/kg): the main component of the essential oil, making it accountable for the major toxicity. The apparition of seizures as toxic manifestations for higher concentrations confirmed that. The essential oil of Brocchia was noted to be classified as slightly, weakly toxic, and the Beta-thujone contents showed to be within the regulatory accepted values, which makes the use of Brocchia safe within the indicated standards.

Volatile Components of the Leaf Oil of Cratoxylum arborescens from Malaysia

Volatile Components of the Leaf Oil of Cratoxylum arborescens from Malaysia

Long-Term Distributed Temperature Sensing Monitoring for Near-Wellbore Gas Migration and Gas Hydrate Formation

Summary Well integrity monitoring has always been a critical component of subsurface oil and gas operations. Distributed fiber-optic sensing is an emerging technology that shows great promise for monitoring processes, both in boreholes and in other settings. In this study, we present a case study of using distributed temperature sensing (DTS) technology to monitor a cemented and plugged well in the Alaska North Slope (ANS). The well was drilled as part of a long-term gas hydrate study, and the downhole DTS data were recorded over a period of approximately 2 years. By applying a temporal gradient and removing instrument instability noise, we reveal subtle (<0.001°C/h) thermal anomalies, which are characterized by brief warming periods followed by longer cooling periods at discrete depths along the borehole. The observed coherent events show an upward trajectory from deeper formations into the overlying permafrost interval, with the thermal anomalies concentrated in relatively coarse-grained sandstone layers. We also observe that the upward migration rate of the DTS anomalies varies with formation lithology and that there is a spatial and temporal correlation between the subsurface events and measured wellhead annular pressures. We interpret that the observed warming events represent the exothermic process of gas hydrate formation that is occurring in association with the upward migration of gas outside the well casing, and this interpretation is confirmed by numerical simulations. These observations demonstrate the ability of suitably processed DTS data to detect subtle processes and highlight the value of DTS technologies for wellbore integrity monitoring.

Neopetasan, the main component of the essential oil from Cyperus sesquiflorus (Cyperaceae)

ABSTRACT Cyperus sesquiflorus is commonly called fragrant kyllinga, fragrant spikesedge, or fragrant flatsedge. It is a cespitose perennial herb with a Pantropical distribution. In Brazil, it is a native species, being commonly named fragrant grass due to its aromatic content. In this study, the essential oil (EO) of C. sesquiflorus was extracted by hydrodistillation with a Clevenger apparatus. Yields of the samples ranged between 0.12% and 0.27% (v/w) oils from fresh and dehydrated whole flowering plants (with roots) and the oil was analyzed by Gas Chromatography/-Mass spectrometry/flame ionization detection (GC-MS/FID) and Gas chromatography/Mass spectroscopy (GC/MS). The main constituent of the oil, neopetasan (3S,4aR,5S)-4a,5-dimethyl-3-(prop-1-en-2-yl)-4,4a,5,6,7,8 hexahydronaphthalen-2(3 H)-one, was isolated by preparative thin layer chromatography (PTLC) and its structure was elucidated by extensive one- and two-dimensional nuclear magnetic resonance (1D/2D-NMR) (COSY, HSQC, HMBC, and NOESY) and Fourier transform infrared (FTIR) spectroscopy in combination with MS and comparison with literature data.