Main Compounds Of Essential Oil Research Articles

Biochemistry of microwave controlled Heracleum sosnowskyi (Manden.) roots with an ecotoxicological aspect

Sosnowski hogweed is an invasive weed in eastern-middle Europe that is dangerous to human health and the environment. The efficacy of its control using chemical and mechanical methods is limited. Electromagnetic radiation (microwaves) could be an environmentally friendly alternative for controlling this species. This study aims to: (1) Determine the effect of varying microwave treatment (MWT) durations on the control of S. hogweed using a device emitting microwaves at 2.45 GHz, 32.8 kW/m2; (2) Evaluate the impact of MWT on soil by an ecotoxicological bioassays; (3) Analyze biochemical changes occurring in the roots during the process. A field study was performed to assess the efficacy of S. hogweed control using MWT in times from 2.5 to 15 min. The MWT-treated soil was collected immediately after treatment (AT) and tested using bioassays (Phytotoxkit, Ostracodtoxkit, and Microtox). Fourteen days AT, the MWT hogweed roots were dug out, air-dried, and analyzed for the content and composition of essential oil, sugars, and fatty acids. According to the ecotoxicological biotests, the MWT soils were classified as non-toxic or low-toxic. The regeneration of hogweed was observed only in non-treated plants (control). Hogweed MWT for 2.5–15 min did not regenerate up to 14 days AT. The average weight of roots in hogweed MWT for 15.0 min was ca. two times smaller than the control plants. Those roots contained significantly higher amounts of sugars and saturated fatty acids than the control. We did not find a correlation between S. hogweed root essential oil content and composition and MWT time. The main compounds of essential oil were p‑cymene and myristicin. No highly photosensitizing compounds were identified in the tested root oil. We conclude that MWT of S. hogweed could be an environmentally safe and prospective control method, but more studies are needed.

Cytotoxic and Antioxidant Properties of Artemisia deserti Essential Oil Obtained by Different Extraction Methods

Background: Artemisia deserti Krasch belongs to Asteraceae family, and has many medicinal properties that used to treat a variety of diseases, including antihypertensive, invigorating blood circulation, antiallergy, antiviral, antitumor, and antioxidant. Methods: The objective of this study was the evaluation of cytotoxic and antioxidant activities as well as the chemical composition of A. deserti essential oil extracted by different extraction methods. These extraction methods included hydro-distillation (HD), salt-HD (Salt pretreatment followed by HD), maceration-HD (maceration pretreatment followed by HD), acid-HD (acid pretreatment followed by HD), ultrasound-HD (ultrasound pretreatment followed by HD), and enzyme-HD (enzyme pretreatment followed by HD). Results: The results revealed that the highest yield of essential oil was achieved by acid-HD (0.48% ± 0.11%). In all methods, the main compounds of essential oil were camphor (44.32%–66.80%), piperiton (14.11%–24.33%), and 1,8-cineole (4.85%–6.75%). The antioxidant property of essential oils was investigated using the DPPH method. Based on the results, the essential oils extracted by acid-HD and enzyme-HD methods had the highest property. The cytotoxic property of A. deserti essential oils was evaluated. The results demonstrated that the essential oil extracted by enzyme-HD indicated the highest cytotoxicity activity against human cervical carcinoma (HeLa) cells in both 24 and 48 h. Based on the gas chromatography-mass spectrometry results, 1,8-cineol, carvacrol, thymol, and myristicin were rich in the essential oil extracted by enzyme-HD, and the highest cytotoxicity activity of essential oil obtained by enzyme-HD method is probably related to these compounds. Conclusion: In addition, it was observed that enzyme-HD is an effective method in the extraction of essential oil with the highest antioxidant and cytotoxic activities.

Variability of morphology, phytochemical traits and essential oil profile of tea (Camellia sinensis (L.) Kuntze) accessions in the southern region of the Caspian Sea

AbstractTea (Camellia sinensis (L.) Kuntze) leaves are an important beverage crop due to their high caffeine content. Although the north of Iran is the main region for high-quality tea plants, there is no document on variations of phenotypic traits of different accessions. The present study was to assess the biodiversity of 12 tea accessions originating from four tea main sites in Iran (Langroud, Siahkal, Kobijar and Bazkiaguorab) using multivariate analysis. Two-year-old tea plants were cultivated in a completely randomized design with five replicates in a greenhouse. One year after plant establishment, phenotypic characteristics were studied. The tea accessions showed different responses in chlorophyll and total ash contents. The highest and lowest amount of caffeine in tea accessions was found in Kobijar A7 and Langroud A2, respectively. Epicatechin was obtained in a 6.48–15.44 mg g−1 range, and the maximum variability was found in epigallocatechin gallate (EGCG), differing from 0.94 to 21.03 mg g−1. Langroud A2 and Bazkiaguorab A11 contained the maximum EGCG and the total polyphenolic content in Bazkiaguorab was greater than other accessions. Heat map analysis showed the maximum variability of EGCG, catechin, and GA among the accessions. The main essential oil compounds were 2-pentyl furan followed by hexanal, gamma-terpinene, octane, ortho-cymene, terpinen-4-ol, alpha-copaene and E-caryophyllene. In conclusion, changes in phytochemical traits caused by genetics and origin can significantly alter the quality of tea compounds. The results of this study can be utilized as raw materials in future breeding projects to improve new cultivars with superior characteristics.

Caccinia macranthera Brand var. macranthera: Phytochemical analysis, phytotoxicity and antimicrobial investigations of essential oils with concomitant in silico molecular docking based on OPLS force-field

This study was conducted to extract the essential oils (EOs) of Caccinia macranthera identify their phytochemicals, evaluate their phytotoxicity, antimicrobial activity and enzyme inhibition effects using in silico molecular docking technique.EOs of aerial parts, seeds, and roots of C. macranthera were extracted and analyzed via Gas chromatography-Mass Spectrometry. The antibacterial activity of EOs were determined on nine microorganisms via disk diffusion and microbroth dilution assays. In addition, the allelopathic properties of EOs were investigated by calculating the IC50s for inhibition of germination, seedling length and seedling weight growth of Cuscuta campestris seeds. In order to assess the possible inhibitory effect of major components of C. macranthera EOs on enzymes inhibiting germination and plant growth, molecular docking was employed against the glutamine synthetase (GS), acetohydroxyacid synthetase (AHAS), and 4-hydroxyphenyl pyruvate dioxygenase (HPPD) enzymes.The main compounds of EOs from aerial parts, seeds, and roots EOs were dihydrocarveol (29.5%), Trimethyl-2-Pentadecanone (13.6%), and Palmitic acid (16.8%), respectively. The maximum antibacterial effect was related to the aerial parts EO against Staphylococcus epidermidis. Phytotoxicity analysis exhibited a concentration-dependent increase (p ≤ 0.05) activity. The aerial parts EO demonstrated a substantial allelopathy effect, with IC50 values of 0.22 ± 0.026, 0.39 ± 0.021, and 0.20 ± 0.025 mg/mL, respectively, on inhibitory germination, seedling length and seedling weight growth of Cuscuta campestris seeds. Molecular docking analyzes showed that Oleic acid was suitable for dynamic stabilization of HPPD (−6.552 kJ/mol) and GS (−7.265 kJ/mol) and Eupatoriochromene had the inhibitory potential against AHAS, with docking score of −4.189 kJ/mol.The current research demonstrated that C. macranthera EOs from its aerial parts have an acceptable phytotoxic activity against Cuscuta campestris weed. The major components of EOs, Oleic acid and Eupatoriochromene, presented the strongest binding with HPPD, GS, and AHAS active sites causing disturbance in germination, photosynthesis and weed growth suggesting it as a natural herbicide for controlling the weeds.

Antimicrobial evaluation of the Patchouli (Pogostemon cablin Benth.) leaf essential oil combination with standard antimicrobial compounds

Pogostemon cablin Benth's leaves, which belong to the Lamiaceae family, are used to make patchouli essential oil (PEO). Sesquiterpenes are the main compounds in essential oil. Antibacterial, antifungal, antiviral, antiemetic, and anti-inflammatory activities are just a few of the many pharmacological actions that are well-known. In this investigation, cefuroxime (CEF), moxifloxacin (MOX), clarithromycin (CLA), fluconazole (FLU), and terbinafine (TER) were combined with patchouli (Pogostemon cablin leaf essential oil). Gram-positive Staphylococcus aureus ATCC 6538, Gram-negative Escherichia coli ATCC 8739, and yeasts Candida albicans ATCC 10231, and C. tropicalis ATCC 750 were tested against all combinations. Drug interaction was given as fractional inhibitory concentrations (FIC) after combinations of the essential oils were tested for their minimum inhibitory concentrations (MIC). The checkerboard method was used to assess antimicrobial interactions, Fluconazole, terbinafine, cefuroxime, and clarithromycin combined with essential oil demonstrated an "additive effect" against Candida strains together with E. coli and S. aureus.

The Effect of Irrigation and Humic Acid on the Plant Yield and Quality of Sweet Basil (Ocimum basilicum L.) with Mulching Application under Semi-Arid Ecological Conditions.

The adoption of suitable irrigation levels (IRL), humic acid doses (HAD) and soil mulching (SM) are important tools for improving the morpho-physiological and biochemical traits of medicinal and aromatic plants. Ocimum basilicum L. cultivated under four IRL: IRL 100 = 100% FC-IRL 75 = 75% FC-IRL 50 = 50% FC-IRL 25 = 25% FC and four HAD: HA 0 = 0.0 Lha-1-HA 10 = 10.0 Lha-1-HA 20 = 20.0 L ha-1-HA 40 = 40.0 L ha-1 were applied in order to evaluate morpho-physiological and biochemical traits under the ecological conditions of Eskişehir in 2016 and 2017. A second trial was conducted with black plastic soil mulch (SM) and compared with the control plots (CP) in 2016. The experiment was arranged in a randomized complete block design with split plots and three replications. The plant height (PH), fresh herb yield (FHY), dry herb yield (DHY), dry leaf yield (DLY), protein ratio (PR), and main essential oil compounds (MEOC) of Ocimum basilicum L. increased and the essential oil ratio (EOR) and essential oil yield (EOY) decreased with increasing IRL (IRL 100 and IRL 75). FHY (7268.3 and 7472.7 kg ha-1) and DLY (635.3 and 637.5 kg ha-1) increased with increasing HAD (HA 20 and HA 40) compared to the values of FHY and DLY at HA 0 (6852.6 and 587.0 respectively). The SM application at IRL 50 increased the PH between 8.8 and 13.5%, FHY 11.7 and 16.7%, DLY 22.5 and 29.2%, and at IRL 75 the EOY between 20.0 and 23.9% compared to CP. In addition, PH, FHY, DLY, and EOY were highest at HA 40 and HA 20. The MEOC (linalool, 1,8-cineole, and (E) - β-bergamotene) under SM were more pronounced at IRL 25 and IRL 50 compared to CP. HA particularly improved FHY, DLY, and the main essential oil compounds that can be considered plant biostimulants, which were defined by several studies and regulations.

Yield, chemical composition, and antioxidant activity of essential oil obtained from Ferula persica oleo-gum-resin: Effect of the originated region, type of oleo-gum-resin, and extraction method

In the present study, we investigated the effect of extraction methods (hydro-distillation, microwave-assisted hydro-distillation, and solvent-free microwave extraction), oleo-gum-resin types (Kokh and Shir), and regions (Sepidan and Darb-e-Behesht) on yield, composition and antioxidant activity of essential oils obtained from oleo-gum-resin of Ferula persica. The results showed that oleo-gum-resins originating from Darb-e-Behesht produced more essential oil than oleo-gum-resins of Sepidan using each of the extraction methods. Each of the extraction methods isolated more essential oil from Kokh samples as compared with Shir. The highest essential oil was achieved by the solvent-free microwave extraction method from Kokh samples. A total of 51 compounds were identified in essential oil samples. Monoterpene hydrocarbons and sulfur compounds were dominant in all essential oils. The main compounds of essential oil in the samples were β-pinene, α-pinene, (E)− 1-Propenyl sec-butyl disulfide, and (Z)− 1-Propenyl sec-butyl disulfide. The antioxidant activity of the essential oils was affected by the region and type of oleo-gum-resin. The essential oils showed less antioxidant activity than butylated hydroxyanisole. The research suggests that the area of oleo-gum-resin collection, type of oleo-gum-resin collected, and essential oil extraction method should be selected and optimized based on the intended purpose and the desired active ingredients. Also, the results show that microwave-assisted hydro-distillation and solvent-free microwave extraction methods can be introduced as quick and suitable alternative methods for extracting essential oils from oleo-gum-resins of F.persica.

Evaluation of the composition and antimicrobial activities of essential oils from four species of Lamiaceae Martinov native to Iran

In this study the essential oils obtained from four different plant species belonging to the Lamiaceae family were extracted by means of hydrodistillation and their composition and antimicrobial activity were evaluated. About 66 components were identified by using gas chromatography-mass spectrometry (GC–MS), and among all, thymol (67.7%), oleic acid (0.5–62.1%), (−)-caryophyllene oxide (0.4–24.8%), α-pinene (1.1–19.4%), 1,8-cineole (0.2–15.4%), palmitic acid (0.32–13.28%), ( +)spathulenol (11.16%), and germacrene D (0.3–10.3%) were the most abundant in all the species tested (i.e. Thymus daenensis, Nepeta sessilifolia, Hymenocrater incanus, and Stachys inflata). In particular, only the composition of essential oils from H. incanus was completely detected (99.13%), while that of the others was only partially detected. Oxygenated monoterpenes (75.57%) were the main compounds of essential oil from T. daenensis; sesquiterpenes hydrocarbons (26.88%) were the most abundant in S. inflata; oxygenated sesquiterpenes (41.22%) were mainly detected in H. incanus essential oil, while the essential oil from N. sessilifolia was mainly composed of non-terpene and fatty acids (77.18%). Due to their slightly different composition, also the antibacterial activity was affected by the essential oil tested. Indeed, the highest antibacterial and antifungal activities were obtained with the essential oil from T. daenensis by means of the inhibition halo (39 ± 1 and 25 ± 0 mm) against Gram-positive strains such as Staphylococcus aureus and Aspergillus brasiliensis. The minimal inhibitory concentration (MIC) and minimal bactericidal/fungicidal concentration (MBC/MFC) of the essential oils obtained from the four species varied from 16 to 2000 μg/mL and were strictly affected by the type of microorganism tested. As an example, the essential oils from H. incanus and S. inflata were the most effective against the Gram-negative bacterium Pseudomonas aeruginosa (MIC 16 and 63 μg/ml, respectively), which is considered one of the most resistant bacterial strain. Therefore, the essential oils obtained from the four species contained a suitable phytocomplexes with potential applications in different commercial area such as agriculture, food, pharmaceutical and cosmetic industries. Moreover, these essential oils can be considered a valuable natural alternative to some synthetic antibiotics, thanks to their ability to control the growth of different bacteria and fungi.

Essential Oil and Hydrosol Composition of Immortelle (Helichrysumitalicum).

The chemical composition of essential oils and hydrosols of immortelle (Helichrysum italicum) stems with leaves obtained by hydrodistillation was identified using gas chromatography coupled with mass spectrometry (GC-MS). One-year-old and two-year-old plants of the same immortelle population, and plants from three Croatian populations, all grown in Slovenia, were included in the study. The main compounds of essential oils of one-year-old and two-year-old plants were α-pinene, α-eudesmol, and rosifoliol. Among essential oils of the Croatian populations, three dominant components were found: α-pinene, geranyl acetate, and 2-phenylethyl tiglate. Both the essential oils and hydrosols of one-year-old plants were more diverse in their compositions than two-year-old plants. The predominant compounds of hydrosols of one- and two-year-old plants were pentan-3-one, 3-octanone, 2,2-dimethylnon-5-en-3-one, and α-terpineol, and in the Croatian populations α-terpineol, 2,6-octadien-1-ol, 2,2-dimethylnon-5-en-3-one, and α-terpineol.

Evaluation of essential oil composition and antioxidant activity of yarrow as influenced by foliar application of humic substance-based products: Using multivariate exploratory method

The growth-promoting ability with the organic fertilizers especially humic substance-based products, it has caused their use to be considered. This research aimed to investigate the effect of foliar application of humic and fulvic acids on essential oil compositions and antioxidant activity of yarrow (Achillea millefolium L.) based on Principal Component Analysis (PCA) and calculating the selection criterion (SC) to identify the main chemical compositions. Treatments consisted of four applied levels of humic acid, HA (Control: 0, HA1: 250, HA2: 500, and HA3: 1000 mg L−1) and fulvic acid, FA (Control: 0, FA1: 250, FA2: 500, and FA3: 1000 mg L−1). According to the results, two PCs had eigenvalues ≥ 1 and showed 80.75% and 65.84% of variance with application of HA and FA, respectively. Based on the results, HA and FA had significant effects on the amount of important medicinal compounds. The main essential oil compounds of different HA- and FA-treated plants were: α-pinene (0.81–6.44%), 1-octen-3-ol (2.68–16.55%), p-cymene (2.85–6.90%), 1,8-cineole (0.45–4.06%), camphor (0.36–6.90%), borneol (3.91–22.83%), myrtenol (2.02–2.88%), thymol (1.01–2.59%), E- caryophyllene (0.39–1.98%), spathulenol (2.3–19.3%), and caryophyllene oxide (5.93–12.60%). According to the calculated coefficient of determination (R2), the maximum positive effects of FA addition were observed for E- caryophyllene, α-terpineol, terpinen-4-ol, and benzaldehyde (R2 = 0.98, 0.93, 0.91, and 0.84, respectively), and that of HA application were obtained for cis-cadin-4-en-7-ol and spathulenol (R2 = 0.99 and 0.92). Results showed that the antioxidant activity of yarrow plant extract significantly improved when FA especially at high levels (i.e., 500 and 1000 mg L−1) was applied. On the other hand, in HA-treated plants, only application of 1000 mg L−1 had a positive effect. Findings of the present study can be used to manage production of medicinal plants and the quality of their products. In addition, in sustainable agriculture, using humic substances can reduce the application rate of chemical fertilizers, thereby maintaining the environment.

Variation of Salvia officinalis L. Essential Oil and Hydrolate Composition and Their Antimicrobial Activity

This study aimed to investigate the chemical composition of steam distillate essential oil and corresponding hydrolate obtained from S. officinalis grown in Serbia, as well as the influence of weather conditions (temperature and precipitations) on their chemical profiles. Furthermore, their antimicrobial activity was investigated in vitro. The main compounds in essential oil were cis-thujone, followed by camphor, trans-thujone, and 1,8-cineole, while hydrolate was slightly different from the essential oil, with camphor, cis-thujone, and 1,8-cineole as the main compounds. Among the eight respiratory-associated microorganisms, Klebsiella oxytoca was the most sensitive to the tested EOs (minimum inhibitory concentration (MIC)/minimal bactericidal/fungicidal concentration (MBC/MFC) were 14.20 and 28.4 μL mL−1, respectively). MIC and MBC values of other tested bacteria ranged between 28.40 and 227.25 μL mL−1 while for Candida albicans MIC/MFC ranged from 28.40/56.81 to 56.81–113.63 μL mL−1. Antibiotic susceptibility patterns for the analyzed eight respiratory-associated microorganisms showed an intermediate level of resistance to commonly used antibiotics such as ampicillin, levofloxacin, and ciprofloxacin. As a preliminary approach to the antimicrobial profiling of the tested EO, the obtained results revealed that the tested samples possess remarkable antibacterial activities and could be used to develop pharmaceutical formulations as an alternative to conventional antibiotic therapy.

Chemical Analysis and Investigation of Biological Effects of Salvia officinalis Essential Oils at Three Phenological Stages.

Salvia officinalis is a medicinal plant used to treat some diseases, including microbial infections and diabetes. Different studies showed the biological and pharmacological properties of this species. The aim of this study was the determination of the chemical compounds of S. officinalis essential oils and the investigation of their antimicrobial, antioxidant, antidiabetic, and anti-inflammatory properties. The chemical compounds of S. officinalis were determined by GC-MS analysis. The antioxidant activity was assessed by DPPH, ABTS, H2O2, and FRAP assays. The in vitro antidiabetic effect was evaluated by the inhibition of α-amylase, α-glucosidase, and lipase activities, and the anti-inflammatory effect was evaluated using the 5-lipoxygenase assay. Moreover, antibacterial activity was assessed against six bacterial strains using agar well diffusion assay and microdilution method. The main compounds in essential oils of S. officinalis at three phenological stages were naphthalenone, camphor, 1.8-cineole, and α-thujone. The full flowering stage essential oil showed the best antioxidant activity with different IC50 values according to the used tests. This oil also exhibited important inhibitory effects at the full flowering stage against α-amylase (IC50 = 69.23 ± 0.1 μg/mL), α-glucosidase (IC50 = 22.24 ± 0.07 μg/mL), and lipase (IC50 = 37.3 ± 0.03 μg/mL). The 5-lipoxygenase inhibitory effect was the best at the full flowering stage (IC50 = 9.24 ± 0.03 μg/mL). The results of the antibacterial evaluation revealed that, at three seasonal periods, S. officinalis essential oil demonstrated strong antibacterial activity. Although the full flowering stage had the best antibacterial activity, there were no significant differences between the three stages. Additionally, the essential oils showed bactericidal effects on Listeria monocytogenes, Staphylococcus aureus, Bacillus subtilis, Proteus mirabilis, Escherichia coli, and Salmonella typhimurium, respectively. The findings of this work showed remarkably that S. officinalis synthesizes essential oils according to different developmental stages. Moreover, it has exhibited interesting biological and pharmacological properties justifying its medicinal effects and suggesting it as a very important source of natural drugs.

Evidence of altitudinal gradient modifying genomic and chemical diversity in populations of Lychnophora pinaster Mart.

Lychnophora pinaster Mart. (Asteraceae) is endemic to the Brazilian Cerrado. It is distributed along the altitudinal gradient of the mountainous ranges of the state of Minas Gerais. This study aimed to evaluate the influence of altitude on the genetic diversity of L. pinaster populations and the effects of altitude and climatic factors on essential oil chemical composition. Essential oils from L. pinaster populations from the north (North 01, North 02, and North 03, 700–859 m) and the Metropolitan region of Belo Horizonte (MhBH 01 and MrBH 02, 1366–1498 m) were analyzed. SNP markers from L. pinaster in these regions and Campos das Vertentes (CV 01, CV 02, and CV 03, 1055–1292 m) were also analyzed. The main compounds in essential oils were 14-hydroxy-α-humulene (North 01 and North 03), cedr-8(15)-en-9-α-ol (North 02), 14-acetoxy-α-humulene (MrBH 01), and 4-oxo-15-nor-eudesman-11-ene (MrBH 02). Hierarchical cluster and heatmap analyses showed that the North and MrBH populations included five different groups, indicating the chemical composition of essential oils is distinct in each population. Furthermore, principal component analysis showed that higher altitudes (1366 m and 1498 m) in the MrBH influence the chemical composition of essential oils, and climatic factors determine the chemical composition in North region. The genetic diversity showed that most alleles are in Hardy–Weinberg equilibrium and imply high genetic variation and genetic polymorphisms between populations. Furthermore, the results of Mantel tests (R = 0.3861517; p = 0.04709529; R = 0.9423121; p = 0.02739726) also showed that higher altitude (>1360 m) shapes the genetic diversity at the MrBH. The genetic structure showed that higher altitudes (>1360 m) contribute to the structure of the MrBH populations, but not to North and CV populations. Therefore, the altitudinal ranges of Minas Gerais mountainous ranges determine the higher genetic and chemical diversity of L. pinaster populations.

Bioactivity of 1,8-Cineole and Essential Oil of Salvia keerlii (Lamiaceae) Against Spodoptera frugiperda

Fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), infests more than 80 crop species and is the principal pest of maize (Zea mays L. (Poaceae) in Mexico. Although insecticides are used to control the pest, they can cause environmental damage and negatively affect human health. Essential oils are an alternate for managing the insect. The aim of this study was to investigate insecticidal and insectistatic activities of essential oil of salvia (Salvia keerlii Benth, Lamiaceae) against larval and pupal S. frugiperda. The oil at 400, 600, and 1,000 mg liter-1 killed 65, 55, and 85% of larvae, respectively, with estimated LC50 of 590.2 mg liter-1, but did not adversely affect pupae. Insectistatic activity at concentrations of 600 and 1,000 mg liter-1 delayed larval development as many as 13.8 days (compared to a negative check). The main compounds of essential oil of S. keerlii were identified by GC-MS as 2-pentanone,4-hydroxy-4-methyl, caryophyllene oxide, and 1,8-cineole. The 1,8-cineole at concentrations of 600 and 1,000 mg liter-1 killed all S. frugiperda larvae, with an estimated LC50 of 249.4 mg liter-1.

Studies on Asteraceae: Chemical Compositions of Essential Oils and Antimicrobial Activity of the Leaves of Vernonia patula (Dryand.) Merr. and Grangea maderaspatana (L.) Poir. from Vietnam

Essential oils from the leaves of Vernonia patula (Dryand.) Merr. and Grangea maderaspatana (L.) Poir. collected from Pu Hoat Nature Reserve, Nghe An Province were studied for their chemical constituents and antimicrobial activity. The main constituents of V. patula were the sesquiterpenes namely β-caryophyllene (28.5 %), caryophyllene oxide (16.6 %), α-copaene (9.0 %), and α-humulene (7.1 %). On the other hand, a mixture of monoterpenes and sesquiterpenes hydrocarbons represented by myrecene (27.7 %), α-humulene (19.7 %), and germacrene D (15.8 %) were the main compounds of essential oils from the leaves of G. maderaspatana. Both essential oils displayed antimicrobial activity against the tested Gram-positive and Gram-negative bacteria with the minimum inhibitory concentrations (MIC) less than 50.0 μg/mL (8.67-24.56 μg/mL). The leaf essential oil of V. patula was the most potent towards Enterococcus faecalis (ATCC 299212) with MIC value of 8.67 μg/mL. The essential oils also showed anti-candidal properties with MIC values of 15.99 μg/mL (V. patula) and 65.67 μg/mL (G. maderaspatana). The chemical components and antimicrobial activity of the V. patula leaf essential oil was reported for the first time.

Modeling the kinetics of essential oil content and main constituents of mint ( Mentha aquatica L.) leaves during thin‐layer drying process using response surface methodology

The purpose of this study was to investigate changes in essential oil content and the main components of mint (Mentha aquatica L.) during thin-layer drying process. Response surface methodology (RSM) based on radial basis functions was used to model the relationships between drying temperature and different drying time (independent variables) and essential oil content and main essential oil compounds of mint (dependent variables). Results of gas chromatography with flame ionization detectior (GC-FID) and gas chromatography-mass spectrometry (GC-MS) analyses showed linalyl acetate, 1,8-cineol, and linalool are the most abundant constituents of essential oil. Inverse multiquadrics model was the best model to predict the percentage of linalyl acetate, 1,8-cineol, and essential oil content, whereas Gaussian model was the best to predict linalool. The efficiency of the selected models was acquired with R2 of 0.9658, 0.9514, 0.9568, and 0.9828 for essential oil content, linalyl acetate, linalool, and 1,8-cineol, respectively. Practical applications Results suggest that essential oil content M. aquatica and its main constituents can be scaled-up by optimizing drying time and temperature. The superior ability of RSM for modeling and monitoring of essential oil content and main components of M. aquatica during drying process as a rapid, accurate, nondestructive, and online method was also observed.

Effect of Tannic Acid Concentration on the Physicochemical, Thermal, and Antioxidant Properties of Gelatin/Gum Arabic–Walled Microcapsules Containing Origanum onites L. Essential Oil

It has long been known that oregano herbs have wide uses and industrial applications due to their high antioxidant activities and other activities of the main essential oil compound, carvacrol, but these compounds are sensitive to oxidation. Gas chromatography-mass spectrometry (GC-MS) analysis was performed to identify the volatile compounds of Origanum onites L. (OOEO), and the main volatile component of OOEO was determined as carvacrol (69.60%). This study aims to develop OOEO-loaded microcapsules by complex coacervation using gum arabic (GA) and gelatin (GE) as wall materials and different concentrations of tannic acid (TA) as a cross-linker. The OOEO microcapsules cross-linked using 2% TA have the highest loading capacity, microencapsulation yield, and efficiency with 36.39%, 83.75%, and 89.61%, respectively. The Fourier transform infrared spectra of the complex coacervates showed characteristic carvacrol peaks, one of the main components of OOEO, indicating that OOEO was successfully encapsulated in the polymer matrix. Thermal gravimetric analysis data revealed that cross-linking with TA affects the thermal stability of the microcapsules attributed to electrostatic interactions between the microcapsule wall and TA. With increasing TA concentration, GE/GA-walled microcapsules exhibited decreased aggregation with increased particle size and absolute zeta potential. This new approach to the production of OOEO-loaded microcapsules provides a high yield strategy with improved physico-mechanical properties and antioxidant activities.

Essential Oil Composition, Antioxidant Activity, Phenolic Compounds, Total Phenolic and Flavonoid Contents from Pomace of Citrus aurantifolia

The massive pomace of Citrus aurantofolia (Christm.) Swingle exhibits a challenging losses exposure difficulty for the processing industries. The resent study was aimed to evaluate the composition and quality of pomace and understand its bioactive compounds to introduce it to different industries such as pharmaceutical, food, medicinal, agricultural etcetera for optimum use. Volatile compounds (VCs) were extracted by water distillation (WD) and Static headspace (SHS) methods. Four different extracts were analyzed for polyphenol compounds identified by HPLC-DAD, total flavonoid content (TFC), total phenolic content (TPC) and antioxidant activity. Limonene (71.7%), b-pinene (8.5%), g-terpinene (7.3%), myrcene (1.8%) and a-pinene (1.7%), were the main compounds of essential oil (EO) of C. aurantifolia pomaceby HD extraction. The dominant VCs of C. aurantifolia were limonene (49.3%) followed by b-pinene (21.7%), g-terpinene (9%), a-pinene (6.8%) and sabinene (4.9%), respectively by static headspace analysis. Trans-ferulic acid was major polyphenol compound in all studied extracts of C. aurantifolia marcs. Methanolic extracts from C. aurantifolia pomaces represented higher antioxidant activity, TPC and TFC than other investigated extracts. This studied marc can be introduced to different industries as a source of bioactive and medicinal natural compounds because of its valuable phytochemical characterization.

α-Thujone exhibits an antifungal activity against F. graminearum by inducing oxidative stress, apoptosis, epigenetics alterations and reduced toxin synthesis

Specific mechanisms contributing to the antifungal activity of α-thujone, one of the main compounds of essential oils in herbs, against Fusarium graminearum, which causes various diseases of cereals, were studied for the first time. Minimum inhibitory concentration (MIC) value of α-thujone was 3.2 μg μL−1 for F. graminearum. Its toxigenic effect was confirmed by WST-1-based cytotoxicity assay. Due to α-thujone treatment, changes in genomic template stability (GTS), type II and III methylation profiles were detected. GTS rates were calculated as 89.33 and 94% according to random amplified polymorphic DNA (RAPD) and inter-retrotransposon amplified polymorphism (IRAP) assays, respectively. Mean values of polymorphisms were 28.92 and 36.42% by evaluating digestion profiles. Gene expression analysis showed α-thujone caused upregulation of mgv1, mst20 and cat genes but downregulation of tri5. Fold change values were 1.86 ± 0.14, 3.10 ± 0.03, 2.56 ± 0.078 and 0.43 ± 0.15 respectively. The acridine orange-ethidium bromide (Ao/Eb) and 2′,7′-dichlorodihydrofluorescein diacetate (DCF-DA) staining assays revealed that α-thujone treatment triggers apoptosis and oxidative stress in F. graminearum at cellular level. Additionally, 6.51-fold increase in catalase activity in comparison with the control was detected. There were no statistically significant changes in water loss rates (WLRs) when Hordeum vulgare L. cv. Akhisar seedlings were treated with α-thujone. According to the water loss rate values, α-thujone is not a potential abiotic stress factor that negatively affects the physiological development of barley plantlets. Outcomes showed that α-thujone leads to serious morphological, genetic, epigenetic, cellular alterations on F. graminearum, so could be a candidate as an alternative herbal antifungal compound.

Anti-inflammatory Activity of Essential Oil from Leaves of Blumea balsamifera (L.) DC through Inhibiting TLR4/NF-kB Signaling Pathways and NLRP3 Inflammasome Activation in LPS-induced RAW264.7 Macrophage Cells

The essential oil (EO) separated from leaves of Blumea balsamifera (L.) DC is extensively applied as conventional medicine by the Miao, Zhuang, and Li nationalities in China to drive skin healing of trauma or burn. Recently, a lot of evidence has proved that EO possesses anti-inflammatory activity. Nevertheless, the underlying molecular mechanisms are still unknown. This research aims to examine the underlying mechanisms of EO in the wound healing areas of skin through evaluating the anti-inflammatory activity, especially two major concerns, the variations of relative proteins in TLR4-NF-κB signaling pathway and NLRP3 inflammasome in LPS-induced RAW264.7 cells. A total of 39 compounds from EO were determined and interpreted by gas chromatography/mass spectrometry (GC/MS). It was observed that the main compounds of EO are (-)-borneol (25.382 %), trans-caryophyllene (24.439 %), camphor (8.991 %), caryophyllene oxide (5.843 %), xanthoxylin (3.968 %), and alloaromadendrene (3.321 %). The anti-inflammation activity and underlying mechanisms are assessed by ELISA, qRT-PCR, and Western blotting in Lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The outcomes reveal that EO can significantly reduce the LPS-induced pro-inflammatory elements TNF-α, IL-1β, IL-6, and inflammatory mediator COX-2 in RAW264.7 cells (P<0.01). Additionally, EO can significantly inhibit the expression of proteins in the NF-κB signaling pathway, such as CD14, TLR4, MyD88, TAK-1, p-IκBα, and NLRP3 inflammasome (P<0.05, P<0.01). These outcomes show anti-inflammatory roles of EO in LPS-induced RAW264.7 cells by decreasing activity of TLR4-NF-κB signaling pathway and inhibiting NLRP3 inflammasome activation, suggesting that EO can be adopted as a hopeful natural commodity preventing and treating inflammatory diseases.