Chemical Composition Of Essential Oil Research Articles

Antioxidant potential and chemical composition of essential oils from Mentha longifolia, Lavandula angustifolia, and Ocimum basilicum grown in the Oued Souf region, Algeria

Antioxidant potential and chemical composition of essential oils from Mentha longifolia, Lavandula angustifolia, and Ocimum basilicum grown in the Oued Souf region, Algeria

Analysis of the Effects of Organic and Synthetic Mulching Films on the Weed, Root Yield, Essential Oil Yield, and Chemical Composition of Angelica archangelica L.

Angelica archangelica L. (Garden angelica) is a medicinal and aromatic plant from the Apiaceae family, originating from North Europe (Iceland, Greenland, and Scandinavian countries). A. archangelica is commonly used in traditional medicine to treat anxiety, insomnia, stomach and intestinal disorders, skin conditions, respiratory problems, and arthritis. This plant is generally cultivated for its root and seed where the essential oil (EO) is concentrated the most. Angelica archangelica cultivation has a lot of challenges but the main one is weed control; so, the aim of this study was to investigate the influence of four different mulch types as non-chemical weed control measures on weediness, fresh root yield, and EO chemical composition and yield from A. archangelica roots. A field trial was conducted with the following six treatments: two organic mulches, two synthetic mulches, and two controls (regular hand-weeded and weeded). The results show that the most present weeds were Ambrosia artemisiifolia, Chenopodium album, Polygonum aviculare, and Polygonum lapathyfolium, but synthetic mulch foils achieved the best weed suppression (100%). These fields also achieved the highest fresh root yield in both of the experimental seasons. The highest EO yield was detected with agrotextile mulch foil at season I (0.41%, v/w) and with the weeded control (0.51%, v/w) at season II, but dominant components at both seasons were α-pinene and β-phellandrene. The results suggest that the agrotextile black and silver–brown mulch foils achieved complete weed suppression, but the agrotextile black mulch foil had a better effect on fresh root yield, EO yield, and its chemical composition.

Sesquiterpene Hydrocarbon-rich Essential Oil from Teucrium viscidum Blume and its Antimicrobial and Mosquito Larvicidal Activities

Objectives This study aimed to investigate the essential oil extracted from the aerial parts of Teucrium viscidum Blume, a perennial herb belonging to the Lamiaceae family, collected in Vietnam. The focus was on determining the essential oil's chemical composition and evaluating its antimicrobial and mosquito larvicidal activities. Methods The essential oil of T. viscidum was analyzed using GC–FID/MS to identify its chemical constituents. The antimicrobial activity was assessed against seven microorganisms using the broth microdilution method to determine minimum inhibitory concentration (MIC) and half-maximal inhibitory concentration (IC50) values. The larvicidal activity was evaluated against Culex quinquefasciatus larvae, with lethal concentration (LC50 and LC90) values calculated after 24 and 48 h of exposure. Results Chemical analysis revealed that the essential oil of T. viscidum was predominantly composed of sesquiterpene hydrocarbons, with ( E)-caryophyllene (47.91%) and germacrene D (19.17%) as the major constituents. The essential oil exhibited significant antimicrobial activity against three Gram-positive bacteria ( Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus), one Gram-negative bacterium ( Pseudomonas aeruginosa), and one yeast ( Candida albicans), with MIC values ranging from 32 to 64 μg/mL and IC50 values ranging from 9.56 to 24.07 μg/mL. The mosquito larvicidal activity of the essential oil showed strong efficacy against C. quinquefasciatus larvae, with LC50 values of 23.07 μg/mL after 24 h and 19.67 μg/mL after 48 h, and LC90 values of 32.90 μg/mL at 24 h and 29.99 μg/mL at 48 h, indicating increased effectiveness with prolonged exposure. Conclusion This study provides a comprehensive analysis of the chemical composition and biological activities of T. viscidum essential oil. The findings highlight its potent antimicrobial and mosquito larvicidal properties, suggesting it as a promising natural alternative to synthetic antimicrobial agents and insecticides. Further research is warranted to explore its mechanisms of action and potential applications in pharmaceuticals and pest control.

Essential Oils of Tunisian Tetraclinis articulata (Vahl) Mast.: Chemical and Biological Insights.

Tetraclinis articulata (Vahl) Mast. is native to the Mediterranean area and belongs to Cupressaceae family. The aim of this study were: i) to determine the chemical composition of essential oils (EOs) of T. articulata obtained from its stems, leaves, and cones using GC coupled to GC/MS; II) to evaluate their antioxidant activity using non enzymatic (DPPH, ABTS and FRAP) and enzymatic methods (catalase activity); III) to evaluated their anti-enzymatic activity on enzyme involved in metabolism and Central Nervous System using spectrophotometric assays. α-Pinene, limonene, and bornyl acetate were the main components of the three EOs. Moreover, the EO from cones showed the best antioxidant activity and was also to increase of catalase activity. All EOs were active against α-amylase in similar way; the EO leaves was more active against α-glucosidase and the EO from cones was more active against cholinesterase. The EOs demonstrated significant inhibition of the mature biofilm of Gram-negative and Gram-positive strains. This highlight the potential uses of T. articulata EOs in the fields of health and agriculture.

Optimization of antimicrobial properties of essential oils under rotating magnetic field

Essential oils (EOs) extracted from Thymus vulgaris L. (TEO) and Rosmarinus officinalis L. (REO) have aroused interest in their application to food preservation or in alternative medicine or aroma-therapy. In this study, the chemical compositions of essential oils were determined and analyzed. The purpose of the investigation was to investigate in detail the activity of essential oils extracted from herbs (thyme and rosemary) and exposed to rotating magnetic filed (RMF) against the model Gram-negative bacteria Escherichia coli The bacterial removal has been optimized by a surface response methodology (RSM). It was shown that TEO in a concentration of 10 µL/50 mL of water resulted in a total bacterial number reduction after 40 min under the RMF. Rosemary's antibacterial effect was much weaker. Thus, we summarized that the rotating magnetic fields at a frequency of 27 Hz can increase the antimicrobial efficiency but the effect depends on the type of essential oil. High-rate bacteria removal was obtain for thyme oil in concentration of 30 µL of thyme oil to 50 mL of bacterial suspension, exposed to RMF at a frequency of 27 Hz for 40–60 min.

Essential Oils from the Leaves and Stem Barks of Pluchea Indica (L.) Less.: Chemical Analysis, Cytotoxicity, Anti-inflammation, Antimicrobial Activity, Molecular Docking, and ADMET Profiling.

Pluchea indica (L.) Less. is a medicinal plant native to Asia. Traditionally, it is known for numerous traditional uses, such as treatments for fever, cough, and digestive issues. The present investigation aims to determine the chemical compositions of essential oils from its fresh leaves and stem barks. By using hydro-distillation and the GC-FID/MS (gas chromatography-flame ionization detection/mass spectrometry) analysis, the studied samples were dominated by sesquiterpene hydrocarbons (76.8-82.2 %) and their oxygenated derivatives (8.4-19.0 %). β-Selinene (42.0-43.5 %) and silphinene (21.1-22.9 %) were the main compounds. Significantly, the stem bark essential oil strongly monitored the growth of four cancer cell lines K562, HeLa, HepG2, and MCF-7 with IC50 values of 2.89-7.34 μg/mL. Both studied samples showed strong anti-inflammatory activity against NO (nitric oxide) production with IC50 values of 21.81-23.18 μg/mL. The studied sample also exhibited antimicrobial activity at different levels. The molecular docking study revealed that β-selinene exhibited the strongest binding affinity for all four cancer-related protein targets: epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), Abelson tyrosine-protein kinase 1 (ABL1), and phosphatidylinositol 3-kinase (PI3 K-α). The ADMET profiles of the major compounds were also predicted to provide insights for further research considerations.

Influence of seasonal variation on the chromatographic profile and physicochemical properties of Basil (Ocimum basilicum) essential oil

Basil (Ocimum basilicum) is important in the Brazilian economy and its essential oil is used in cooking, industry and perfumery, and has antimicrobial properties. The chemical composition of essential oils can be altered by the action of various factors, whether internal or external to the plant, such as genetics, temperature, water availability and seasonality. The aim of this research was to assess whether seasonality interferes with the chromatographic profile and physicochemical characteristics of basil essential oil. The study was carried out by investigating the technical reports of the Haje Insumos company on the chemical composition using gas chromatography, physical-chemical analysis (density, refractive index and humidity) and organoleptic analysis (appearance, color and odor). Due to the presence of the linalool component in greater quantity, the oil analyzed is characterized as being of the linalool chemotype. The product showed no alterations to its organoleptic characteristics and all the results were in accordance with its specification. In addition, one of the batches had a higher moisture content, which may be related to the environmental conditions at the time of year, which requires attention as water can trigger a hydrolysis reaction in fat-soluble molecules. It is understood that seasonality may be related to changes in the essential oil, and it was possible to contribute to the recognition of this plant's product.

Chemical composition and antimicrobial activity of essential oil of Inula crithmoides L. growing in Egypt

The study aimed to determine the chemical composition and antimicrobial properties of the essential oil of Inula crithmoides L. growing in Egypt. The essential oil was obtained from the flowers of Inula crithmoides L. with a yield of 0.18% v/w through hydro distillation. Gas chromatography-mass spectroscopy analysis was used to identify the chemical composition of the essential oil. The antimicrobial activity of the essential oil was tested against selected species of Gram-positive, Gram-negative bacteria, and Candida species using the disc diffusion method, and MICs were determined using the broth micro-dilution method. Twenty-two compounds were identified in the essential oil of Inula crithmoides, with the major components being thymol acetate (32.4%), p-cymene (15.3%), and thymol (14.3%). The essential oil exhibited significant antimicrobial activities against Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa, with an MIC of 25 µg/mL for E. coli and 50 µg/mL for other sensitive bacteria. The oil exhibited significant antifungal activity against all the tested Candida species with MIC 50 µg/mL. This study is the first to explore the chemical composition and antimicrobial activity of the essential oil of Inula crithmoides growing in Egypt, demonstrating its potential as a natural antiseptic agent.

Phytochemical profiling, molecular docking, and ADMET evaluation of essential oils from Anaphalis busua and Anaphalis margaritacea in Uttarakhand's Himalayan Terrain

BackgroundThe study focuses on a comparative analysis of essential oils derived from two species of the Anaphalis genus, namely Anaphalis busua and Anaphalis margaritacea, collected at varying elevations in the hilly terrain of Uttarakhand. The investigation aims to explore the phytochemical composition, conduct in silico molecular docking studies, and evaluate ADMET properties of the essential oils to understand their potential bioactivity. MethodsEssential oils were extracted from the whole plants using the hydrodistillation method, and GC–MS was employed for compound identification. A total of 31 compounds were identified in A. busua and 32 in A. margaritacea, constituting 87.86 % and 87.83 % of the total composition, respectively. Major compounds included isocaryophyllene, caryophyllene oxide, geranyl-α-terpinene, α-pinene, γ-muurolene, δ-cadinene, humulene, and copaene. ResultsMolecular docking studies were conducted using PyRx software on ten notable compounds as ligands, targeting cyclooxygenase-2 (COX-2) and human peroxiredoxin 5 to assess antioxidant and anti-inflammatory activities. Isocaryophyllene, with concentrations of 14.07 % (A. busua) and 17.82 % (A. margaritacea), exhibited significant binding affinities of -5.7 and -7.2 kcal/mol against 1HD2 and 4COX, respectively. ConclusionThe research provides valuable insights into the chemical composition of essential oils from Anaphalis plants and validates their bioactive potential through in silico analysis. Isocaryophyllene emerges as a key compound with noteworthy binding affinities, emphasizing its importance in the medicinal and pharmacological applications of essential oils derived from A. busua and A. margaritacea. The results enhance our understanding of the therapeutic potential of Anaphalis essential oils, opening avenues for future research in natural products and drug discovery.

Morphological traits, yield, antioxidant activity and essential oil composition of oregano as affected by biostimulant foliar applications

Biostimulants are interesting products which can promote the plant growth and improve its qualitative traits. In this research, the effects of foliar applications of four biostimulants on oregano (Origanum vulgare L.) crop have been investigated by evaluating morphological parameters, fresh and dry yield, antioxidant activity, total phenolic content, and chemical composition of essential oil. The highest plant height (78 cm), inflorescence height (22.2 cm), inflorescences+leaves dry yield (0.5 t ha−1), dry matter yield (38.3 %) and essential oil yield (3.4 %) were obtained in plants treated with biostimulant BlueN®, composted of Methylobacterium symbioticum SB23. Plants treated with Acadian MPE®, containing vitamins, amino acids and proteins, and betaines, showed the highest total phenolic content (60.3 GAE mg mL−1). The combination of 21 traits with principal component analysis (PCA) allowed to discriminate the biostimulant Biostimol Plus plus Peptamin-V Plus®, based on Ascophyllum nodosum extract and other elements as nitrogen, carbon, manganese, zinc and iron chelates, in a correlated way with p-cymene, α-thujene, α-terpinene, β-myrcene contents, showing values significantly higher. The heat-map identified two main clusters where the treatments with biostimulants were clearly separated from the control. Biostimulant treatments influenced the chemical composition of essential oil by increasing the number of components, monoterpene hydrocarbons and sesquiterpene hydrocarbons contents. Therefore, biostimulants can play an important role with a view to sustainable oregano cultivation by representing a safe source of nitrogen and especially for organic farming.

Antibacterial Activities and Chemical Composition of Essential Oils from Sweet Orange (Citrus sinensis), Lemon Grass (Cymbopogon citratus), and Lime (Citrus aurantifolia) Peels

Antibacterial Activities and Chemical Composition of Essential Oils from Sweet Orange (Citrus sinensis), Lemon Grass (Cymbopogon citratus), and Lime (Citrus aurantifolia) Peels

Effect of cultivation and geographical location on chemical composition and enantiomeric distribution in linalool-rich Origanum dubium Boiss. essential oils obtained at different growth stages

ABSTRACT The current study is objected to investigate the essential oil yields, chemical compositions, and enantiomeric distribution of wild and cultivated linalool rich Origanum dubium Boiss. essential oils obtained at pre-flowering, initial flowering, and post-flowering growth stages. Wild plant materials are collected from Mediterranean region of Turkey. Samples were also cultivated in Mediterranean and Aegean coastlines of Turkey in the experimental fields of Ministry of Agriculture and Forestry of Turkey. O. dubium samples yielded between 6.7 and 9.7% (mL/100 g) of essential oils. The compositions were dominated by oxygenated monoterpenes (98.2–98.9%). Linalool was detected as the major compound in all essential oils (97.0–97.6%). The dominant enantiomer was discovered as (R)-(-)-linalool with a 99.3–99.4% enantiomeric purity. The essential oil yields, chemical compositions and enantiomeric distributions were found to be constant regardless of cultivation, geographical locations or different growth stages. The result of this manuscript indicates that by culturing linalool chemotype of O. dubium, the industrial need for (R)-(-)-linalool could be met at more affordable costs.

Cytotoxic Activity and Phytochemical Analysis of Artemisia biennis Essential Oils at Different Growth Stages

Background: The Artemisia genus is well-known for its medicinal properties, particularly in Iranian traditional medicine. Artemisia biennis, a species within this genus, is widely distributed across Iranian rangelands. Objectives: This study aimed to evaluate the cytotoxic activity and chemical composition of essential oils (EO) isolated from the aerial parts of A. biennis in Iran at different growth stages. Methods: The aerial parts of A. biennis from northeast Iran were collected during June (early vegetative stage), July (pre-flowering stage), August (full-flowering stage), and October (late vegetative stage). The essential oils (EOs) of the A. biennis species were extracted by hydro-distillation using a Clevenger-type apparatus and analyzed using gas chromatography–mass spectrometry (GC/MS). The cytotoxic activity of the EOs against normal fibroblasts, MCF-7, and HT-29 cell lines was evaluated using the MTT assay. Results: Data from GC/MS analysis revealed that (Z)-nerolidol (22.62 - 54.4%), (E)-β-farnesene (6.89-16.38%), and (Z)-tonghaosu (12.33 - 18.61%) were the most abundant chemical constituents. The essential oil (EO) of A. biennis was characterized by a high content of oxygenated sesquiterpenes, with (Z)-nerolidol being the main constituent identified. Based on the MTT assay, the EO of the plant species collected in June exhibited the most potent cytotoxicity against MCF-7 (IC50 = 2.84 ± 0.15 µg/mL) and HT-29 cell lines (IC50 = 2.41 ± 0.2 µg/mL). Conclusions: The growth stage of A. biennis affects EO yields, the composition of extracted secondary metabolites, and cytotoxic activity. A. biennis EOs can be considered potential sources of cytotoxic phytochemicals.

Influence of diurnal harvesting times on essential oil yield and chemical composition of lemongrass, palmarosa and tulsi

Essential oil yield and chemical composition of most of the aromatic crops are affected by environmental, agrochemical and genetic factors. One of such factors are Harvesting Time (HT’s), optimizing which may result in higher essential oil production with better quality. The present study was carried out to determine the effect of HT’s on three different aromatic crops [lemongrass, palmarosa and Ocimum sanctum (CIM-Ayu)] at different diurnal times (9.00 A.M 12.00 P.M and 3.00 P.M) in a day and the same was repeated thrice on alternate days from in the same fields. The results indicated that HT at 3.00 PM had higher essential oil content in all the three aromatic crops. But, the influence of HT on the quality of essential oil was specific to the different crops studied in this report. The quality of essential oil obtained from lemongrass harvested at 12.00 PM was found to be better as it showed more percentage of citral whereas the essential oils obtained from palmarosa and O. sanctum harvested at 3.00 PM were better as they showed more percentage of geraniol and eugenol respectively. This research not only refines essential oil production strategies but also underscores the crop-specific impact of harvesting times. The meticulous temporal analysis, coupled with statistical validation, contributes novel insights, providing practical benefits for industries reliant on these aromatic crops.

Employment of MQ gas sensors for the classification of Cistus ladanifer essential oils

The chemical composition of essential oils (EOs) from Cistus ladanifer has a huge variability throughout the year, impacting the oil quality. Nowadays, EO analytic chemistry techniques, which are expensive and destroy the sample, are utilized to measure the chemical composition. In the paper, we propose a combination of low-cost sensors and machine learning based system. As low-cost sensors, seven gas sensors are combined to obtain up to 36 features. Regarding machine learning, 31 multiclass classification algorithms are applied. Data from sensors were collected for 33 samples of EO from Cistus ladanifer. The generated dataset was split into training and test datasets, with 75 % of the data for training. The datasets were created to ensure a homogeneous chemical composition distribution on both training and test datasets. There were three target chemical compounds: Alpha-pinene and Viridiflorol as individual compounds and Terpenic Hydrocarbons as a group of chemical compounds. The value of the percentage of each targeted compound is converted into a categoric variable with 5 possible values, 1 being the lowest concentration and 5 being the maximum one. The data of the MQ-sensors were included as the input for the models, and each one of the targeted chemical compounds was selected as an output for different models. The input features were ranged using different algorithms for the feature selection process. The results indicate that there is no valid classification model for Viridiflorol, and limited accuracy is achieved for Alpha-pinene. Meanwhile, for Terpenic Hydrocarbons, an accuracy of 91.6 % is achieved. It is important to highlight that these accuracies were attained when a reduced number of features were included, ranging the number of features from 11 to 13. This is the first case in which MQ-based gas sensors, or other metal oxide sensors, are used to correctly determine the concentration of a chemical compounds in a complex matrix formed by dozens of compounds. This system will provide a cheap method to determine the quality of EOs and confirm the benefits of combining low-cost sensors with machine learning.

Effect of stationary factors on the yield and chemical composition of essential oils of Tetraclinis articulata (Vahl) Masters from Sdama Chergui massif’s (Tiaret, North-West Algeria)

This paper aims to study the influence of exposure, altitude, and soil pH on the yield and chemical composition of essential oils (EOs) from the leaves of Tetraclinis articulata (Vahl) Masters, developed in the Sdama Chergui massif in northwestern Algeria. These EOs were obtained by hydrodistillation, resulting in average yields of 0.33±0.13 %, 0.29±0.07 %, 0.24±0.07 %, and 0.2±0.03 %, recorded at the south, west, north, and east exposures, respectively. Upon analyzing the obtained EOs by gas chromatography coupled with mass spectrometry (GC/MS), a total of chemical molecules grouped into 22 families were identified. The predominant compounds were Bornyl acetate (9.14 %, 7.95 %, 11.20 %, and 9.78 %), Limonene (5.03 %, 7.18 %, 5.76 %, and 5.41 %), α-Pinene (4.97 %, 5.26 %, 5.09 %, and 4.79 %), Camphor (7.53 %, 3.69 %, 3.01 %, and 5.91 %), and Borneol (5.20 %, 6.26 %, 4.93 %, and 5.11 %). Additionally, the analysis of these molecules by Factorial Analysis of Mixed Data (PCAmix) revealed that exposure, altitude, and soil pH have little effect on the yield and chemical composition of the essential oils of Tetraclinis articulata. Finally, careful attention to stationary parameters is crucial for obtaining essential oils of high quality and optimal quantity.

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.

Phytochemical analysis and insecticidal effect of essential oils from Myroxylon peruiferum (Leguminosae) and Eugenia gracillima (Myrtaceae) for the control of Aedes aegypti (Diptera: Culicidae)

ABSTRACT The aim of the present study was to evaluate the chemical composition of essential oils from Myroxylon peruiferum and Eugenia gracillima and determine the larvicidal potential of the oils against Aedes aegypti. Essential oils from the leaves and young stems of M. peruiferum (EOLMP and EOAMP) and the leaves of E. gracillima (EOLEG) were obtained through hydrodistillation. The major constituents of EOLMP were α-pinene (18.0%) and δ-cadinene (14.2%); the major constituents of EOAMP were spathulenol (22.9%) and β-elemene (12.4%) and the major constituents of EOLEG were δ-elemene (40.4%) and germacrene D (25.2%). The two oils extracted from M. peruiferum were very active against A. aegypti larvae and had similar lethal concentrations (LC50 = 0.7 mg/mL). The oil extracted from E. gracillima had an LC50 of 1.51 mg/mL. The essential oils from M. peruiferum and E. gracillima constitute promising sources for the formulation of novel insecticides for the control of the mosquito Aedes aegypti.

The leaf essential oils of Meiogyne virgata (Blume) Miq., M. vietnamica Jaikhamseub, T.A.Le & Chaowasku, and Orophea polycarpa A.DC.: Chemical composition, antimicrobial activity, molecular docking, and toxicity profiling

The present study aims to describe the chemical composition of essential oils from three Vietnamese Annonaceae species, Meiogyne virgata, M. vietnamica, and Orophea polycarpa, and their antimicrobial activity. Essential oils were extracted by hydro-distillation. From the GC-FID/MS (gas chromatography-flame ionization detection and mass spectrometry) analysis, the leaf essential oil of M. virgata was reported to contain the major compound germacrene D (42.48%). Spathulenol (24.51%), bicyclogermacrene (18.58%), β-selinene (11.14%), and germacrene D (8.20%) can be seen as the main compound in M. vietnamica leaf essential oil. α-Phellandrene (39.35%), bicyclogermacrene (13.07%), β-phellandrene (10.87%), and limonene (8.27%) represented O. polycarpa leaf essential oil. Essential oil of M. virgata leaves exhibited strong antimicrobial activity against the Gram (+) bacterium Bacillus subtilis ATCC 5230, the Gram (-) bacterium Escherichia coli ATCC 8739, and the fungus Aspergillus niger ATCC 9587 with the same MIC value of 16 μg/mL. The docking method showed that germacrene D has the ΔGbinding (binding affinity) values of –6.68, –5.265, and –5.602 kcal/mol with the proteins E. coli DNA gyrase, B. subtilis TasA, and A. niger PhyA, respectively. Alkyl and pi-alkyl interactions are the main contributors to the binding affinity between the studied proteins and ligands. Furthermore, germacrene D is predicted to have low toxicity and is not active against any of the considered organ targets.

Insecticidal and Repellent Activity of Essential Oils from Copaifera reticulata, Citrus paradisi, Lavandula hybrida and Salvia sclarea Against Immature and Adult Stages of Ctenocephalides felis felis.

The flea Ctenocephalides felis (Siphonaptera: Pulicidae), parasitizes dogs and cats globally, acting as a vector for various pathogens affecting both animals and humans. Growing interest in environmentally friendly, plant-based products prompted this study. The aim of the study was to determine the chemical composition of essential oils (EOs) from Copaifera reticulata, Citrus paradisi, Lavandula hybrida and Salvia sclarea, assessing their insecticidal and repellent properties, determining lethal concentrations (LC50 and LC90), and evaluating residual efficacy in vitro against Ctenocephalides felis felis. Gas Chromatography with Flame Ionization Detector analyzed EO composition. In vitro tests involved preparing EO solutions at various concentrations. Ten specimens from each life stage (egg, larva, pupa, adult) were used for insecticidal activity assessment. Adulticidal activity was assessed using 10cm2 filter paper strip, each treated with 0.200mL of the test solution. Immature stages activities were evaluated using 23.76cm2 discs of the same filter paper, each treated with 0.470mL of the test solution. Mortality percentage was calculated using (number of dead insects × 100) / number of incubated insects. Probit analysis calculated LC50 values with a 95% confidence interval. Major EO constituents were β-caryophyllene (EOCR), linalool (EOLH), linalyl acetate (EOSS), and limonene (EOCP). LC50 values were obtained for all stages except for the essential oil of C. paradisi. All oils showed repellent activity at 800μg/cm2. OECR exhibited greater residual efficacy. Each EO demonstrated superior insecticidal activity against specific C. felis felis stages.