Main Components Of Essential Oil Research Articles

Essential Oils of The Leaves of Syzygium hemilamprum (F. Muell.) Craven & Biffin.: Chemical Analysis, Antimicrobial, Mosquito Larvicidal, ADMET,and Molecular Docking Studies.

Chemical constituents from essential oil and n-hexane extract of S hemilamprum leaves were first identified. The obtained essential oil was dominated by monoterpene hydrocarbons (71.55%), and their oxygenated derivatives (20.2%), in which β-pinene (31.5%), limonene (19.4%), α-pinene (12.3%), and α-terpineol (7.4%) were the principal agents. The n-hexane extract was characterized by monoterpene hydrocarbons (42.2%) and non-terpenic compounds (34.0%) with β-pinene (32.8%), and n-hexadecane (10.2%) being the major compounds. Both two samples showed antimicrobial activity against the Gram (+) bacterium Staphylococcus aureus ATCC 6538, the Gram (-) bacterium Pseudomonas aeruginosa ATCC 9027, and the yeast Saccharomyces cerevisiae ATCC 2601 with the same MIC value of 128 µg/mL. Remarkably, they strongly inhibited mosquito larvicidal activity against Aedes aegypti and Culex quinquefasciatus larvae with the LC50 and L90 values of less than 20 µg/mL for 24 and 48 h treatments. A molecular docking study suggested limonene and α-terpineol as potent inhibitors of the mosquito odorant binding protein. In silico study on the physicochemical and ADMET properties of the main components of essential oils was also conducted.

CgLS mediates limonene synthesis of main essential oil component in secretory cavity cells of Citrus grandis ‘Tomentosa’ fruits

d-Limonene is the predominant component of essential oil from Exocarpium Citri Grandis, known for its antibacterial, antioxidant, insecticidal, and anti-inflammatory properties. The synthesis, transport, and accumulation of d-limonene in Citrus grandis ‘Tomentosa’ fruits are regulated by limonene synthase (LS) and its associated regulatory genes. This study addresses the gap in understanding the spatiotemporal cytological changes of LS and its regulatory genes. Through cytochemical techniques, we investigated the distribution of essential oil in the plastids, endoplasmic reticulum, and vacuoles of secretory cavity cells. We identified the LS-encoding gene CgLS via transcriptomics and demonstrated in vitro that CgLS catalyzes the formation of d-limonene from geranyl diphosphate (GPP). Transient overexpression of CgLS increased monoterpene limonene accumulation, while TRV virus-induced gene silencing reduced it. CgLS expression levels and d-limonene content showed spatiotemporal consistency with fruit development, with in situ hybridization revealing predominant expression in secretory cavity cells. Immunocytochemical localization indicated that CgLS is primarily located in the endoplasmic reticulum, plastids, and vacuoles. Our findings suggest that CgLS is translated in the endoplasmic reticulum and transported to plastids and vacuoles where d-limonene synthesis occurs. This study provides comprehensive insights into the characteristics of CgLS and its role in d-limonene synthesis at the tissue, cellular, and molecular levels in C. grandis ‘Tomentosa’.

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.

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.

Unraveling the effective inhibition of α-terpinol and terpene-4-ol against Aspergillus carbonarius: Antifungal mechanism, ochratoxin A biosynthesis inhibition and degradation perspectives

Aspergillus carbonarius, a common food-contaminating fungus, produces ochratoxin A (OTA) and poses a risk to human health. This study aimed to assess the inhibitory activity of tea tree essential oil and its main components, Terpene-4-ol (T4), α-terpineol (αS), and 3-carene (3C) against A. carbonarius. The study showed αS and T4 were the main antifungal components of tea tree essential oil, which primarily inhibit A. carbonarius growth through cell membrane disruption, reducing antioxidant enzyme activities (catalase, peroxidase, superoxide dismutase) and interrupting the tricarboxylic acid cycle. Furthermore, αS and T4 interacted with enzymes related to OTA biosynthesis. Molecular docking and molecular dynamics show that they bound mainly to P450 with a minimum binding energy of −7.232 kcal/mol, we infered that blocking the synthesis of OTA precursor OTβ. Our hypothesis was preliminarily verified by the detection of key substances in the OTA synthesis pathway. The results of UHPLC-QTOF-MS2 analysis demonstrated that T4 achieved a degradation rate of 43 % for OTA, while αS reached 29.6 %, resulting in final breakdown products such as OTα and phenylalanine. These results indicated that α-terpinol and Terpene-4-ol have the potential to be used as naturally safe and efficient preservatives or active packaging to prevent OTA contamination.

Transcriptional regulation and functional validation analysis of the McbZIP1 in Mentha canadensis L.

Monoterpenoids are the main components of Mentha canadensis essential oil. Monoterpene biosynthetic pathways have been explored, but the regulatory mechanisms remain unclarified. We identified an abscisic acid (ABA)-inducible A-type basic leucine zipper (bZIP) transcription factor McbZIP1 that was localized in the nucleus and positively regulates monoterpene synthesis. McbZIP1 was expressed in most M. canadensis tissues and was induced under ABA, mannitol, and NaCl treatments. McbZIP1 had transcriptional activity in yeast and the N terminus (amino acids 75–117) was sufficient for transactivation. Yeast one-hybrid and Dual-Luciferase assays showed that McbZIP1 binds to ABA-responsive elements in the promoter region of limonene synthase gene. Yeast two-hybrid and biomolecular fluorescence complementation assays revealed that McbZIP1 interacts with McSnRK2.4. Overexpression of McbZIP1 in peppermint resulted in dramatically up-regulated monoterpene biosynthesis gene levels and increased menthol contents. The results support a transcriptional regulation mechanism in which McbZIP1 serves as a positive regulator of menthol biogenesis. These findings contribute to the molecular mechanism of monoterpenoid biogenesis, which may have uses in genetic engineering and menthol production.

(-)-Carvone Inhibits Oxytocin-induced Writhing Via Uterine Relaxation in Rodents.

(-)-Carvone, a ketone monoterpene, is the main component of essential oils from several medicinal plants and has been reported to have anti-arthriric, anticonvulsive, antidiabetic, anti-inflammatory, anticancer, and immunomodulatory effects. Therefore, this study aimed to investigate the spasmolytic activity of (-)-carvone in rodent models. The isolated virgin rat uterus was mounted in an organ bath apparatus, and the relaxing effect of ( -)-carvone and its mechanism of action were evaluated in tonic contractions induced by carbachol, KCl, PGF2α, or oxytocin. The animal model of primary dysmenorrhea was replicated with the injection of estradiol benzoate in female mice for three consecutive days, followed by intraperitoneal administration of oxytocin. Non-clinical acute toxicity evaluation was also performed. (-)-Carvone potency and effectiveness were larger in carbachol (pEC50 = 5.41 ± 0.14 and Emax = 92.63 ± 1.90% at 10-3M) or oxytocin (pEC50 = 4.29 ± 0.17 and Emax = 86.69 ± 1.56% at 10-3M) contractions. The effect of ( -)-carvone was altered in the presence of 4-aminopyridine, glibenclamide, L-NAME, or methylene blue. Mice pre-treated with (-)-carvone at a dose of 100mg/kg showed a significant reduction in the number of writhing after oxytocin administration. No toxicity was observed after oral administration of 1g/kg ( -)-carvone. Taken together, we showed that (-)-carvone reduced writhing by a spasmolytic effect, probably through the participation of KV and KATP channels and the nitric oxide pathway.

Identification of Transcription Factors of Santalene Synthase Gene Promoters and SaSSY Cis-Elements through Yeast One-Hybrid Screening in Santalum album L.

The main components of sandalwood heartwood essential oil are terpenoids, approximately 80% of which are α-santalol and β-santalol. In the synthesis of the main secondary metabolites of sandalwood heartwood, the key gene, santalene synthase (SaSSY), can produce α-santalene and β-santalene by catalyzed (E, E)-FPP. Furthermore, santalene is catalyzed by the cytochrome monooxygenase SaCYP736A167 to form sandalwood essential oil, which then produces a fragrance. However, the upstream regulatory mechanism of the key gene santalene synthase remains unclear. In this study, SaSSY (Sal3G10690) promoter transcription factors and SaSSY cis-elements were screened. The results showed that the titer of the sandalwood cDNA library was 1.75 × 107 CFU/mL, 80% of the inserted fragments identified by PCR were over 750 bp in length, and the positivity rate of the library was greater than 90%. The promoter region of the SaSSY gene was shown to have the structural basis for potential regulatory factor binding. After sequencing and bioinformatics analysis, we successfully obtained 51 positive clones and identified four potential SaSSY transcriptional regulators. Sal6G03620 was annotated as the transcription factor MYB36-like, and Sal8G07920 was annotated as the small heat shock protein HSP20 in sandalwood. Sal1G00910 was annotated as a hypothetical protein of sandalwood. Sal4G10880 was annotated as a homeobox-leucine zipper protein (ATHB-15) in sandalwood. In this study, a cDNA library of sandalwood was successfully constructed using a yeast one-hybrid technique, and the transcription factors that might interact with SaSSY gene promoters were screened. This study provides a foundation for exploring the molecular regulatory mechanism involved in the formation of sandalwood heartwood.

Main Components of The Semboro Variety of Siam Orange Peel Essential Oil Prepared Using Water Distillation Method

The maximum production potential for low quality oranges is 15% or 9,057 tons/year, the potential for orange peel waste is 50% of the total weight of oranges or the equivalent of 4,500 tons of orange peel waste The average yield of orange peel essential oil is 0.6%, resulting in a potential of 27 tons/year. The aim of this research is to obtain information regarding the best heating temperature in the distillation process and to identify the main components of Siam orange peel essential oil of the Semboro variety. The research was carried out using a laboratory-scale water distillation system, with a distillation flask capacity of 1 liter, with 150 g of orange peel as raw material at a distillation process heating temperature of 250°C and 300°C. The yields of 1.9 mL and 0.9 mL of Siam orange peel essential oil were obtained 1.083% and 0.513% respectively. The specific gravity of Siam orange peel essential oil is 0.855 g/cm3 and 0.886 g/cm3 respectively, the main components are 29 and 18 components respectively. An important finding of this research is that at a distillation process with heating temperature of 250°C, yields a limonene content of 16.10%, whereas heating at 300°C results in 7.69% limonene content. Keywords: Limonene; Low grade orange peel; Heating temperature; Quality essential oil.

The effect of different hydrodistillation times on the composition and yield of bergamot (Citrus bergamia Risso) peel essential oil and a comparison of the cold‐pressing method

AbstractBergamot (Citrus bergamia Risso) is not consumed as fresh fruit as other members of Citrus. Bergamot essential oil has a unique aroma. Bergamot essential oil is a very valuable product used in perfumery, cosmetics, aromatherapy and food industry due to its beautiful scent and functional properties. As with other Citrus species, the composition of bergamot essential oil can vary according to harvest time, climate and extraction technology. Bergamot essential oil could be obtained by cold press extraction or distillation method. Within the scope of the study, the effect of four different hydrodistillation (HD) times (5, 10, 60 and 120 min) on the composition of bergamot essential oil obtained from Turkish fruits was investigated. In the first 60 min, 96.11% of the total essential oil was obtained. Research findings have shown that the distillation time is quite effective in the composition of bergamot essential oil. Limonene, linalool and linalyl acetate, which are the main components of bergamot essential oil, varied in the range, 42.36%–53.25%, 5.59%–12.18% and 20.84%–26.73%, respectively, with respect to distillation time. In cold press method, bergamot essential oil has lower linalool/linalyl acetate ratio (0.15) compared to HD method and a higher quality essence was obtained.

Contributions of γ-Aminobutyric Acid (GABA) Receptors for the Activities of Pectis brevipedunculata Essential Oil against Drosophila suzukii and Pollinator Bees.

The γ-aminobutyric acid (GABA) receptors play pivotal roles in the transmission of neuronal information in the nervous system of insects, which has led these proteins to be targeted by synthetic and natural products. Here, we assessed the insecticidal potential of the essential oil of Pectis brevipedunculata (Gardner) Sch. Bip., a neotropical Asteraceae plant used in traditional medicine, for controlling Drosophila suzukii (Matsumura) adults by feeding exposure. By using in silico approaches, we disentangle the contribution of GABA receptors and other potential neuronal targets (e.g., acetylcholinesterase, glutathione-S-transferases) in insects that may explain the essential oil differential activities against D. suzukii and two essential pollinator bees (Apis mellifera Linnaeus and Partamona helleri Friese). Neral (26.7%) and geranial (33.9%) were the main essential oil components which killed D. suzukii with an estimated median lethal concentration (LC50) of 2.25 µL/mL. Both pollinator forager bee species, which would likely contact this compound in the field, were more tolerant to the essential oil and did not have their diet consumptions affected by the essential oil. Based on the molecular predictions for the three potential targets and the essential oil main components, a higher affinity of interaction with the GABA receptors of D. suzukii (geranial -6.2 kcal/mol; neral -5.8 kcal/mol) in relation to A. mellifera (geranial -5.2 kcal/mol; neral -4.9 kcal/mol) would contribute to explaining the difference in toxicities observed in the bioassays. Collectively, our findings indicated the involvement of GABA receptors in the potential of P. brevipedunculata essential oil as an alternative tool for controlling D. suzukii.

Comparison of the cytotoxicity and zebrafish embryo toxicity of insect repellent ingredients: p-Menthane-3,8-diol synthesized by green chemistry from Eucalyptus citriodora and N,N-diethyl-meta-toluamide

Bio-sourced insect repellents are becoming more popular due to their safer applications. Known for its strong fly-repellent property, Cis, trans-para-menthane-3,8-diol (PMD) is the main component of the lemon eucalyptus essential oil and is synthesized from citronellal. In April 2005, US Centers for Disease Control approved two fly repellents that do not contain N,N-diethyl-meta-toluamide (DEET), including PMD. Due to the intentional and pervasive human exposure caused by DEET as insect repellent, concerns have been raised about its toxicological profile and potential harm to people. We hypothesized PMD would have a different toxicological profile than DEET. We synthesized PMD from Eucalyptus citriodora using green chemistry methods and analyzed its structures by 1H-NMR,13C-NMR, and GC/MS spectral methods. We used MTS assay to determine the percentage inhibition of PMD and DEET on keratinocyte (human epidermal keratinocyte [HaCaT]) cells. The xCelligence system was used and followed at real time. Effects of PMD and DEET on zebrafish embryo development were monitored and levels of lipid peroxidation, glutathione-S-transferase (GST), superoxide dismutase (SOD), and acetylcholinesterase (AchE) were evaluated at 72 h post-fertilization using spectrophotometric methods. Our results showed that while DEET inhibited human keratinocyte cell growth, while imporved cell viability and proliferation was exposed in PMD exposed group. In zebrafish embryos, PMD was less toxic in terms of development, oxidant-antioxidant status, and AChE activities than DEET. Based on these results we suggest an efficient method using green chemistry for the synthesis of PMD, which is found to be less toxic in zebrafish embryos and human keratinocyte cells.

Essential oil analysis of Rhaponticum repens (L.) Hidalgo, and its application in green synthesis of iron nanoparticles to remove Cr (VI) ions from aqueous solutions

Acroptilon repens is a widespread weed in Asia, and has a complicated taxonomy. Recent taxonomical treatment explored that Acroptilon species must be classified in the genus Rhaponticum. Therefore, the scientific name of this species has been converted into Rhaponticum repens. In the current study, essential oil composition, and its ability to green synthesis of iron nanoparticles for future use to adsorb Cr (VI) ions pollution of aquatic solution were evaluated for the first time. The GC-MS analysis revealed oxygenated monoterpenes constituted great proportion of the essential oil, with 1,8-cineole and camphor as the main essential oil components. Several appropriate methods, including UV-Vis, FTIR, XRD, SEM, DLS, and VSM revealed the green synthesis of a mixture of Fe3O4 and Fe2O3 nanoparticles by the extracted essential oil. Sizes of the produced nanoparticles were not equal and detected in the range of 3 to 50 nm, with an average size of 31.5 nm and the magnetic property of 15 emu/g. The green-synthesized nanoparticles could adsorb Cr (VI) ions pollution from aquatic solutions. However, under an optimum condition, the Cr (VI) ions adsorption capacity and removal were 167.6 mg/g and 91%, respectively. Findings revealed the major essential oil composition highly differed from those reported in the previous phytochemical studies. Although the synthesized nanoparticles were not uniform, they could remove Cr (VI) ions pollution.

Study on mechanism of inhibiting proliferation of head and neck cancer cells by citral, active ingredient of lemon essential oil

To explore the active substances exerting anti-tumour effect in lemon essential oil and the molecular mechanism inhibiting the proliferation of head and neck cancer cells SCC15 and CAL33, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay(MTT) was utilized to identify the active component inhibiting the proliferation of head and neck cancer cells, namely citral. The IC_(50) of citral inhibiting the proliferation of head and neck cancer cells and normal cells were also determined. In addition, a 5-ethynyl-2'-deoxyuridine(EdU) staining assay was used to detect the effect of citral on the proliferation rate of head and neck cancer cells, and a colony formation assay was used to detect the effect of citral on tumor sphere formation of head and neck cancer cells in vitro. The cell cycle arrest and apoptosis induction of head and neck cancer cells by citral were evaluated by flow cytometry, and Western blot was used to detect the effect of citral on the expression levels of cell cycle-and apoptosis-related proteins in head and neck cancer cells. The findings indicated that citral could effectively inhibit the proliferation and growth of head and neck cancer cells, with anti-tumor activity, and its half inhibitory concentrations for CAL33 and SCC15 were 54.78 and 25.23 μg·mL~(-1), respectively. Furthermore, citral arrested cell cycle at G_2/M phase by down-regulating cell cycle-related proteins such as S-phase kinase associated protein 2(SKP2), C-MYC, cyclin dependent kinase 1(CDK1), and cyclin B. Moreover, citral increased the cysteinyl aspartate-specific proteinase-3(caspase-3), cysteinyl aspartate-specific proteinase-9(caspase-9), and cleaved poly ADP-ribose polymerase(PARP). It up-regulated the level of autophagy-related proteins including microtubule associated protein 1 light chain 3B(LC3B), sequestosome 1(P62/SQSTM1), autophagy effector protein Beclin1(Beclin1), and lysosome-associate membrane protein 1(LAMP1), suggesting that citral could effectively trigger cell apoptosis and cell autophagy in head and neck cancer cells. Furthermore, the dual-tagged plasmid system mCherry-GFP-LC3 was used, and it was found that citral impeded the fusion of autophagosomes and lysosomes, leading to autophagic flux blockage. Collectively, our findings reveal that the main active anti-proliferation component of lemon essential oil is citral, and this component has a significant inhibitory effect on head and neck cancer cells. Its underlying molecular mechanism is that citral induces apoptosis and autophagy by cell cycle arrest and ultimately inhibits cell proliferation.

Identification and variation analysis of the composition and content of essential oil and fragrance compounds in Phoebe zhennan wood at different tree ages.

Wood essential oil and wood products with special fragrances are high value-added forest products. Despite the availability of essential oil and volatile organic compounds (VOCs) from Phoebe zhennan wood, their variation and dependence on tree age have not been examined. After essential oil extraction and wood processing, the yields and compositions of essential oils and VOCs in wood from P. zhennan trees of different ages (10a, 30a, and 80a) were determined. The yield of essential oil from 30a wood was significantly greater than that from 10a and 80a wood. Liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) revealed 672 and 41 volatile compounds, respectively, in the essential oil and wood, the majority of which exhibited large fluctuations in relative content and composition depending on tree age. Sesquiterpenoids, fatty acids and conjugates may greatly contribute to the main components of essential oil from wood. Almost all major sesquiterpenoid compounds, such as caryophyllene α-oxide, eudesmo, and cubebene, were identified in the essential oils from the 30a and 80a wood, and their relative contents were much greater than those in the 10a wood. The main components of the wood fragrance were sesquiterpenoids. The types and relative contents of sesquiterpenoids from wood increased with tree age. These results suggest that choosing wood from trees of a suitable age will significantly improve the efficiency of wood utilization.

Artificial Biosynthetic Pathway for Efficient Synthesis of Vanillin, a Feruloyl-CoA-Derived Natural Product from Eugenol.

Eugenol, the main component of essential oil from the Syzygium aromaticum clove tree, has great potential as an alternative bioresource feedstock for biosynthesis purposes. Although eugenol degradation to ferulic acid was investigated, an efficient method for directly converting eugenol to targeted natural products has not been established. Herein we identified the inherent inhibitions by simply combining the previously reported ferulic acid biosynthetic pathway and vanillin biosynthetic pathway. To overcome this, we developed a novel biosynthetic pathway for converting eugenol into vanillin, by introducing cinnamoyl-CoA reductase (CCR), which catalyzes conversion of coniferyl aldehyde to feruloyl-CoA. This approach bypasses the need for two catalysts, namely coniferyl aldehyde dehydrogenase and feruloyl-CoA synthetase, thereby eliminating inhibition while simplifying the pathway. To further improve efficiency, we enhanced CCR catalytic efficiency via directed evolution and leveraged an artificialvanillin biosensor for high-throughput screening. Switching the cofactor preference of CCR from NADP+ to NAD+ significantly improved pathway efficiency. This newly designed pathway provides an alternative strategy for efficiently biosynthesizing feruloyl-CoA-derived natural products using eugenol.

Towards Sustainable Pest Management: Toxicity, Biochemical Effects, and Molecular Docking Analysis of Ocimum basilicum (Lamiaceae) Essential Oil on Agrotis ipsilon and Spodoptera littoralis (Lepidoptera: Noctuidae)

Over the last decade, essential oils (EOs) have become potential ingredients for insecticide formulations due to their widespread availability and perceived safety. Therefore, this study aimed to evaluate the toxicity and biochemical efficacy of basil (Ocimum basilicum) (Lamiaceae) against two destructive pests Noctuidae, Agrotis ipsilon (Hufnagel) and Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae). In addition, a molecular docking study was performed to gain insight into the binding pattern between glutathione S-transferase (GST) and linalool, the main component of EO. GC–MS analysis of O. basilicum EO revealed that linalool is the most abundant compound (29.34%). However, the toxicity tests showed no significant difference between the values of LC50 of O. basilicum EO to A. ipsilon and S. littoralis. On the other hand, the sublethal experiments indicated that treating the second instar larvae with LC15 or LC50 values of O. basilicum EO significantly prolonged the larval duration in both insects, compared to the control. Regarding the biochemical effect of O. basilicum EO, the treatments significantly impacted the activity of detoxification enzymes. A notable elevation in glutathione S-transferase (GST) activity was recorded in A. ipsilon larvae compared with a reduction in S. littoralis larvae. The molecular docking analysis revealed that linalool bonded with the amino acid serine (SER 9) of GST, indicating its binding affinity with the enzyme. The obtained results could offer valuable insights into the mode of action of O. basilicum and can encourage the adoption of sustainable pest control practices that incorporate essential oils.

RELATIONSHIP BETWEEN BIOCHEMICAL INDICATORS AND PHENOTYPICAL CHARACTERISTICS OF THYME (THYMUS VULGARIS L.)

Introduction. Thyme (Thymus vulgaris L.) is a sought-after medicinal crop, the raw materials of which are included in the Pharmacopoeias of several countries and are widely used in scientific medicine. Due to the presence of strong intraspecific diversity in thyme, it seems interesting to identify phenotypic characteristics that most likely indicate the presence of certain pharmacologically significant compounds. The presence of such information will allow targeted selection both in natural populations and during the hybridization of cultivars and the development of new varieties. The purpose of the work was to identify phenotypic traits indicating a high content of essential oil and thymol in thyme, the amount of phenolic compounds, flavonoids and tannins. Material and methods. Samples and varieties of thyme from different geographical origins were selected as objects. Biometric, anatomical indicators and yield were determined in the flowering phase. The essential oil content was determined by Clevenger hydrodistillation method. Component composition was determined by gas chromatography. The amount of phenolic compounds and tannins according to the Folin-Ciocalteu method in aqueous-alcoholic extract calculated as gallic acid. The determination of flavonoids in the aqueous-alcoholic extract was carried out using the spectrophotometryс method calculated as rutin. Results. As a result of the research, no signs were found indicating a high content of essential oil. Flavonoid content calculated as rutin had a negative correlation (−0.72) with stomatal density. A negative relationship was noted between the intensity of coloring of the pistil and anthers and the content of the total phenolic compounds calculated as gallic acid (0.71 and 0.72, respectively). Large stomata on both the underside and upper side of the leaf may indicate a high tannin content (0.8 and 0.88). All studied components of common thyme belonged to the thymol type, and the content of this component ranged from 37.6 to 80.8%. An increased content of thymol in essential oil is observed such signs as an elongated leaf shape (leaf index R = 0.78), lack of downward curling of the edges of the leaf blade (R = –0.78) and pronounced veins on the underside of the leaf (R = 0.92). Large stomata on the lower epidermis also indicate an increased proportion of thymol in the essential oil (R = 0.78). When analyzing the interdependence between the content of the main components of essential oil, it was noted that there is a close negative correlation between the content of p-cymene and thymol (R = –0.91) and carvacrol (R = –0.88). Conclusion. As a result of the research, phenotypic and anatomical characteristics were identified that make it possible to diagnose promising samples of common thyme, which will help speed up the selection process.

Full-Length Transcriptome Sequencing and RNA-Seq Analysis Offer Insights into Terpenoid Biosynthesis in Blumea balsamifera (L.) DC.

Blumea balsamifera (L.) DC., an important economic and medicinal herb, has a long history of being used as a traditional Chinese medicine. Its leaves have always been used as a raw material for the extraction of essential oils, comprising large amounts of terpenoids, which have good therapeutic effects on many diseases, such as eczema, bacterial infection, and hypertension. However, the genetic basis of terpenoid biosynthesis in this plant is virtually unknown on account of the lack of genomic data. Here, a combination of next-generation sequencing (NGS) and full-length transcriptome sequencing was applied to identify genes involved in terpenoid biosynthesis at five developmental stages. Then, the main components of essential oils in B. balsamifera were identified using GC-MS. Overall, 16 monoterpenoids and 20 sesquiterpenoids were identified and 333,860 CCS reads were generated, yielding 65,045 non-redundant transcripts. Among these highly accurate transcripts, 59,958 (92.18%) transcripts were successfully annotated using NR, eggNOG, Swissprot, KEGG, KOG, COG, Pfam, and GO databases. Finally, a total of 56 differently expressed genes (DEGs) involved in terpenoid biosynthesis were identified, including 38 terpenoid backbone genes and 18 TPSs, which provide a significant amount of genetic information for B. balsamifera. These results build a basis for resource protection, molecular breeding, and the metabolic engineering of this plant.

Content analysis, nanoparticle forming potential and acaricidal effects on Tick (Hyalomma marginatum) of essential oils from two common Thymbra species

In this study, the fatty acid, essential oil and aroma composition of Thymbra sintenisii Bornm. & Aznav. subsp. sintenisii Bornm. & Aznav (TSS) and Thymbra sintenisii Bornm. & Azn. subsp. isaurica P.H.Davis (TSI) were determined by GC-MS. The cytotoxic activity was determined with MTT assay and antioxidant activities were determined with DPPH, ABTS, CUPRAC methods. Urease, acetyl, butyryl, angiotensin, α-amylase, tyrosinase, elastase, and collagenase enzyme inhibition activities of these species were also determined. The acaricidal effects of essential oils from aerial parts of TSS and TSI on ticks and the nanoparticle formation potential of their essential oils with AgNO3 were determined and compared. The main components of TSS essential oil and aroma were determined as carvacrol and o-cemen (66.78 and 35.44%, respectively), the major components of TSI essential oil and aroma were carvacrol and γ-terpinene (63.78 and 31.44%, respectively). The species exhibited remarkably high antioxidant activity, particularly in the ABTS and CUPRAC methods. It was also determined that the butyrylcholinesterase and acetylcholinesterase enzyme inhibition activities (Inhibition%: 76.12±0.83 and 74.13±0.33, respectively) of the species were quite high. Moderate antimicrobial activity against the bacteria was observed for both essential oils, with MIC values ranging from 312 to 1250 μg/mL. Moreover, essential oils of these species showed good acaricidal activity on Hyalomma marginatum (LC50: 11.82 μg/mL for TSS; LC50: 57.64 μg/mL for TSI). The high antioxidant, anticholinesterase, and acaracidal activities observed in both species are attributed to the presence of carvacrol in their essential oils. The species have potential to be used in food supplements-preservatives, pharmaceutical industry.