Traditional Hydrodistillation Research Articles

Chemical Composition of Hydrodistillation and Solvent Free Microwave Extraction of Essential Oils from <i>Plectranthus amboinicus </i>and <i>Melaleuca cajupati</i> Leaves and their Repellent Activity

Extraction of the native plants Plectranthus amboinicus and Melaleuca cajupati leaves have been carried out using traditional hydrodistillation (steam distillation) and solvent free microwave-assisted extraction methods at different temperatures and microwave irradiation powers. The chemical compositions of the essential oils extracted were identified using gas chromatography analysis. The ideal extraction time for Pletranthus amboinicus and Melaleuca cajupati were 120 min with microwave power 200 W and 400 W, respectively with the calculated extraction yield were 0.034 % and 0.276 %, respectively. In this paper, the results of the selected microwave powers, first oil drops, and extraction time are presented as well as the findings of the chemical compositions present in both plants are also discussed.

Investigation and assessment of the quality of Japanese mint essential oil (Mentha arvensis) originated from various geographical regions in Vietnam

In this study, the effects of distillation methods including hydro-distillation (HD) and microwave hydro-distillation (MHD) on essential oil extractions of Mentha arvensis L. in Lam Dong (LD), Ho Chi Minh City (HCMC), and Ba Ria-Vung Tau (BR) were investigated for the yield and chemical composition of the essential oil. The results showed that the use of MHD (0,075 %) was more effective on oil extraction yield than traditional HD (0.053 %). Optimal Distillation parameters were found distillation times of 20 and 110 minutes and material/water ratio of 1:2,5 and 1:6 g/mL for MHD and HD, respectively. The MHD method was subjected to comparing qualitative chemical compositions from Japanese essential oils in BR, LD, and HCMC, Vietnam. The GC-MS analysis results showed that menthol was a major constituent in the essential oil and was responsible for the distinctive smell and flavor of the Japanese mint. Moreover, the menthol content in oil from LD ound was up to 70.6 % higher than that in HCMC (69.45 %) and BR (67.85 %). In conclusion, the mint essential oil is distilled from ingredients in different regions of Vietnam, such as LD, HCMC, BR-VT, all give essential oil a characteristic scent and a relatively high menthol content of about 60 % - 70 %.

Enhanced extraction of clove essential oil by ultrasound and microwave assisted hydrodistillation and their comparison in antioxidant activity

Clove essential oil (CEO) is recognized for its variety of bioactivities and is widely used in the fields of food and pharmaceuticals. Eugenol is the main component that causes the oil's effectiveness. This study included a bibliometric analysis to demonstrate the novelty of the CEO extraction method. A combination of ultrasound and microwave techniques was utilized to enhance the efficiency of hydrodistillation (HD) extraction of essential oil from clove bud in terms of extraction yield, extraction rate, and eugenol composition, which is a strong antioxidant agent. Meanwhile, the effects of ultrasonic extraction temperature and time, microwave distillation power and time, and the ratio of clove to water were also investigated. The optimum conditions were as follows: ultrasonic extraction was at 40 °C for 45 min, microwave distillation power was 400 W for 45 min, and the clove to water ratio was 1:20 (g/mL). The ultrasound pretreatment prior to microwave-assisted hydrodistillation (U-MHD) method obtained the CEO, which had a significantly higher extraction yield (16.80 ± 0.26 %) and a greater amount of eugenol (78.49 %) than the CEOs obtained by traditional HD and MHD methods. Corresponding to the antioxidant activity of CEO from U-MHD, it possessed the strongest DPPH radical scavenging activity with an IC50 value of 2.79 ± 0.05 μg/mL, and it was comparable to the activity of eugenol. This is the first occurrence of CEO extraction employing the U-MHD procedure. This process could be used to enhance the bioactivity of CEO as well as its extraction efficiency, easy operation, rapid extraction, and eco-friendly technique. In terms of cost-analysis, MHD stands out as the most economically viable extraction method, boasting the lowest cost per 100 g product. The obtained results serve as fundamental data for implementing the scaling up of extraction processes to an industrial level.

Recovery of essential oils from the withered flowers of Magnolia soulangeana Soul.-Bod. by microwave-assisted hydrodistillation with uniform heating and its new application in the hypolipidemic field

This study innovatively designed a microwave-assisted hydrodistillation method with uniform heating to extract the essential oil from the withered flowers of Magnolia soulangeana Soul.-Bod., in which the addition of the rotating unit is applied to improve the uneven heating of plant materials caused by the fixation of the flask and the energy point in the microwave system, and the soaking pretreatment unit is used to fully swell the plant cells and accelerate the overflow of essential oils. Meanwhile, the significance of the independent variables that may affect the yield of essential oil and the optimal conditions were screened and optimized by means of response surface methodology, and the results showed that the introduction of the rotation unit and soaking pretreatment unit increased the yield of essential oil by 16.67% and 20%, respectively, which highly promoted the increase of the yield and extraction rate of essential oil. Moreover, the samples obtained by this new method are rich in terpene compounds, such as eucalyptol, δ-cadinene, α-muurolene, and germacrene D, which is consistent with the results of traditional hydrodistillation, and also further illustrates the safety of this method. And the hypolipidemic activity of these compounds was also verified, and the main compound in the essential oil that exerts the hypolipidemic activity may be δ-cadinene, and its possible target for reducing total cholesterol content is Niemann-Pick C1-like 1. In addition, this study also shows that this new method shows lower energy consumption and environmental pressure and is very promising to replace the existing method for the large-scale preparation of essential oils.

Extraction process optimization of essential oil from Mellissa officinalis L. using a new ultrasound-microwave hybrid-assisted Clevenger hydrodistillation

The limited efficiency of traditional hydrodistillation extraction methods has hindered the development of essential oils (EOs). This study introduces an innovative method for enhancing the production of EOs from Mellissa officinalis L. The method involves ultrasonic and microwave-coupled Clevenger hydrodistillation, which utilizes a proprietary distillation device (PDD) extraction process. Yield optimisation was determined systematically by response surface methodology following single-factor experiments. The maximum extraction yield (0.21 ± 0.0019%) was achieved when the liquid-to-solid ratio, microwave extraction power, and microwave extraction time were set to 9.74 mL/g, 559.60 W, and 75 mins, respectively. The new process produced 74.79% and 73.55% more EOs than the electric furnace heating-assisted PDD and the microwave-assisted traditional Clevenger hydrodistillation. The combination of microwave and a modified PDD showed better results for EOs extraction, and it has great potential to improve the production efficiency of M. officinalis EOs.

An efficient approach to obtain essential oil, oleanoic acid, 3-O-acetyloleanolic acid and betulinic acid from fresh leaves of Melaleuca bracteata F. Muell. 'Revolution Gold' using microwave and gravity-assisted solvent-free distillation followed by extraction

A green and efficient microwave and gravity-assisted solvent-free distillation followed by extraction (MGSFDE) approach was presented to extract essential oil, oleanoic acid, 3-O-acetyloleanolic acid and betulinic acid from Melaleuca bracteata F. Muell. 'Revolution Gold' leaves. In this process, essential oils were obtained by solvent-free distillation with the synergistic action of microwave and gravity using in situ water in fresh plant cells. Meanwhile, most of the water contained in fresh plants is removed, which simplifies the operation for the subsequent extraction of strongly alcohol-soluble triterpenic acids such as oleanoic acid, 3-O-acetyloleanolic acid and betulinic acid (avoiding the drying process of plant materials), increasing the yield of triterpenic acid. For the extraction process of essential oil, the second-order kinetic model showed a better fit than the first-order kinetic model. Through single-factor, face-centered central composite design and BoxBehnken design, the operational parameters affecting MGSFDE were systematically optimized. Under optimized parameters, the yield of M. bracteata leaf essential oil was 6.05 ± 0.17 mL/kg DW, and the yields of oleanoic acid, 3-O-acetyloleanolic acid and betulinic acid were 28.99 ± 1.45, 9.21 ± 0.46 and 0.91 ± 0.05 mg/g DW, respectively. The types of compounds in the essential oil extracted at 540 W were the ones that were most similar to those in the traditional hydrodistillation (HD), and the relative content was higher, according to the results of GCMS, principal component analysis, and heatmap analysis. Because of its greater yields, lower power consumption, lower CO2 emissions, and lower water wastage, MGSFDE is assumed to be an effective and ecologically friendly extraction process with the potential to replace traditional methods and provides a great reference for extraction studies of other aromatic plants containing volatile and nonvolatile active ingredients.

Comparative Study of Microwave-assisted Extraction and Hydro-distillation Methods for Extracting Essential Oil from Melaleuca cajuputi in Southern Vietnam: Yield, Composition, and Efficiency Analysis

Aims: This study aimed to the extraction of Melaleuca cajuputi essential oils by microwave-assisted extraction method. The comparison for productivity of microwave-assisted extraction method and traditional hydro-distillation method was also established to figure out the optimum condition for the isolation process.
 Methodology: Microwave-assisted extraction method was employed for the isolation of Melaleuca cajuputi essential oils. The components contained in Melaleuca cajuputi essential oils were analyzed by gas chromatography-mass spectrometry. Standard methods were applied to investigate the characteristics of extracted essential oils, including density, acid index, saponification index and ester index.
 Results: The major components in the product included caryophyllene (21.45%), γ-terpinene (6.14%), α-terpinolen (7.12%), 1R-α-pinene (3%), α-caryophyllene (10.75%), α-terpineol (0.64%), 4-terpinenol (1.34%), eucalyptol (0.86%) and α-terpinen (0.77%). The highest yield of 0.42% (w/w) was obtained at optimum condition, which was water to raw material ratio of 3.5 mL/g, and extraction time of 210 minutes.
 Conclusion: The comparison of extraction process performed by microwave-assisted extraction and traditional hydro-distillation method proved that microwave-assisted extraction was effective for essential oil extraction in both quality and quantity.

Chemical constituents and biological activities of the seed essential oil from Michelia tonkinensis grown in Thanh Hoa province, Viet Nam

AbstractEssential oils (EOs) from the seed of Michelia tonkinensis were extracted in four ways hydrodistillation (HD), microwave‐assisted hydrodistillation (MHD), ultrasound‐assisted hydrodistillation (UHD) and enzyme‐assisted hydrodistillation (EHD). The chemical constituents of these EOs were analysed by gas chromatography (GC‐FID) and gas chromatography/mass spectrometry (GC/MS). Phenylpropanoids were the main components in which safrole is the dominant constituent (82.98‐91.53%), followed by monoterpene hydrocarbons (5.26‐11.94%). In comparison with traditional hydrodistillation method (HD only), the EOs obtained from the MHD, UHD and EHD methods have the higher safrole contents (91.32%, 90.96% and 90.25%, respectively). The essential oils were also tested for their antioxidant, anti‐imflammatory, antimicrobial and cytotoxic activities. The HD essential oil sample showed inhibitory activity against 6/8 tested microorganisms, i.e., Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Bacillus subtillis, Candida albicans, and Saccharomyces cerevisiae. The MHD and EHD exhibited the inhibitory activity against three strains E. coli, A. niger and F. oxysporum. The UHD inhibited E. coli and F. oxysporum.

Microwave-Assisted Hydrodistillation of the Insecticidal Essential Oil from Carlina acaulis: A Fractional Factorial Design Optimization Study.

Recently, microwave-assisted hydrodistillation (MAH) has been reported as an innovative technique leading to increased essential oil (EO) extraction yield, coupled with reduced extraction time and energy costs. The EO of Carlina acaulis L. (Asteraceae), mainly constituted by carlina oxide (>95%) and conventionally obtained through traditional hydrodistillation (HD), has been reported as extremely effective against several arthropod vectors and pests of medical and economic importance with limited impact on non-target species, including mammals. This study aimed to the optimization of the EO extraction through MAH by using a one-step design of experiments (DoE) approach that allowed us to relate the characteristics of the produced EOs with the applied experimental conditions using mathematical models. The preliminary screening allowed us to optimize the protocol only by the extraction time, skipping complex data analysis. Moreover, the comparison of the optimized MAH conditions with traditional HD pointed out the higher efficiency of MAH in terms of EO yield (0.65 and 0.49% for MAH and HD, respectively) and extraction time (210 min for MAH). The results obtained confirmed the promising role that MAH could have in C. acaulis EO extraction, with increased yield and reduced extraction time, water consumption, and energy costs, and being employable on an industrial scale, with special reference to insecticidal and acaricidal formulations.

Exploration of Cucumber Waste as a Potential Biorefinery Feedstock

The exploration of cucumber waste as a potential biorefinery feedstock is reported. Initially, extractives (essential oils) were isolated from cucumber waste via vacuum microwave hydro-distillation (VMHD). The yield and quality of the extractive were compared with respect to traditional hydro-distillation (HD). The essential oils were obtained over a range of microwave power (500, 750, 1000 W) and vacuum pressures (100, 200, 300 mbar). The highest quality (0.49 wt %) was obtained at a microwave irradiation power of 500 W and a vacuum of 300 mbar. VMHD is much quicker and more energy-efficient than HD. Within the context of a zero-waste biorefinery, the extractive-free residues were the solid residues from two different extraction methods were compared and characterized by ATR-IR, 13C solid-state NMR spectroscopy, SEM, TGA, and CHN elemental analysis. The resultant residues are cellulosic-rich, and no significant changes were observed with VMHD and HD treatment. The results indicated that the utilization of these residues can provide an efficient, inexpensive, and environment-friendly platform for the production of cellulosic materials.

Efficient separation of Cinnamomum camphora leaf essential oil and in vitro evaluation of its antifungal activity

Cinnamomum camphora leaf essential oil (CEO) was extracted using enzymatic-ultrasound pretreatment followed by microwave assisted extraction (EUP-MAE) method and simultaneously studied as a mycelial growth inhibitor against five important pathogens which cause potato dry rot. The optimum EUP-MAE conditions with a real CEO yield of 19.23 ± 0.12 mg/g were obtained through Plackett–Burman design and Box–Behnken design as follows: 3 % of enzyme dosage, 2 h of pretreatment time, 5 of pH, 210 W of ultrasound power, 50 °C pretreatment temperature, 16 mL/g of water to solid ratio, 30 min of microwave time and 500 W of microwave power. Compared to the reference methods, EUP-MAE possessed a highest CEO yield than these of ultrasound-microwave assisted extraction (U-MAE) and traditional hydrodistillation (HD). Gas chromatography-mass spectrometry (GC–MS) analysis demonstrated that eucalyptol, camphor, and α -terpineol were the three main constituents of CEO. Results from in vitro antifungal activity assay revealed that the mycelial growths of all the five tested Fusarium solani , Fusarium culmorum , Fusarium trichothecioides , Fusarium sporotrioides , and Fusarium avenaceum were apparently affected by CEO. These findings not only provide a potential paradigm for the separation of plant essential oil, but also guarantee a promising utilization of the CEO for potato protection to control the Fusarium spp.

Effect of Response Surface Methodology-Optimized Ultrasound-Assisted Pretreatment Extraction on the Composition of Essential Oil Released From Tribute citrus Peels.

The traditional hydrodistillation (HD) and ultrasound-assisted pretreatment extraction (UAPE) methods were proposed to obtain essential oil (EO) from Tribute citrus (TC) peels. The Box-Behnken design was employed to optimize the HD and UAPE procedures. Moreover, gas chromatography-mass spectrometry (GC-MS) and electronic nose (E-nose) were applied to identify the discrepancy of the extraction methods. The yield of EO extracted by UAPE (114.02 mg/g) was significantly higher than that by HD (85.67 mg/g) (p < 0.01) undergoing 40 min short time-consuming UPAE. A total of 28 compounds were extracted from the TC peels as terpenes were the predominant components. d-Limonene was the most vital compound in the T. citrus essential oil (TCEO), accounting for 86.38% of the total volatile concentration in HD and 86.75% in UAPE, respectively, followed by α-pinene, sabinene, γ-myrcene, and β-phellandrene. The chart of radar and graphic of the principal component analysis by E-nose displayed no significance, which was similar to the GC-MS results. This study demonstrated that UAPE is an efficient and short time-consuming method for TCEO extraction, which provides a promising method for the separation of EO from aromatic plant materials.

Microwave-assisted hydrodistillation extraction based on microwave-assisted preparation of deep eutectic solvents coupled with GC-MS for analysis of essential oils from clove buds

In recent years, deep eutectic solvents (DESs) as green and sustainable solvents have been widely used in the effective extraction of natural products. Usually, DESs are synthesized by heating and stirring method which takes a long time and energy. In this case, a microwave assisted preparation technique was used to form DESs for saving time and energy. And the DESs as pretreatment solvents were combined with microwave-assisted hydrodistillation (MAHD) for the extraction of essential oils (EOs) from the clove buds in this work. The maximum essential oils yield of 4.60% was obtained with the microwave power of 600 W, the pretreatment time of 5 min and the hydrodistillation time of 40 min using a deep eutectic solvent composed of choline chloride and lactic acid (molar ratio with 1:2). In addition, the essential oil was analyzed by gas chromatography-mass spectrometry (GC-MS), a total of 40 compounds were identified. Compared with MAHD, water-based MAHD and traditional hydrodistillation (HD), the content and composition of essential oil extracted by DES-based MAHD were higher. Thus, the combination of deep eutectic solvents with a microwave-assisted technique in this study provided an eco-friendly way of extracting essential oils.

Solar energy‐based extraction of essential oils from cloves, cinnamon, orange, lemon, eucalyptus, and cardamom: A clean energy technology for green extraction

AbstractConventional essential oil extraction systems cannot meet the green extraction concepts and sustainable development goals (SDGs). Therefore, there is a need to develop alternative systems based on clean energy. The present study aims to investigate the possibility of essential oil extraction using solar energy without utilizing synthetic solvents. Hence, an eco‐friendly solar energy‐based extraction system (SEE) was developed to extract essential oils from cloves and cinnamon barks, orange and lemon peels, eucalyptus leaves, and cardamom seeds. Essential oils were assessed in terms of yield, physical properties, and chemical composition using gas chromatography–mass spectrometry assay. Also, the process sustainability was analyzed by the green extraction evaluation approach, and results were compared with those of traditional hydro‐distillation (THD). Replacing THD with SEE increased the extraction time by 0.65, 0.80, 0.41, 0.61, 0.39, and 0.45 h for processing clove, cinnamon, orange, lemon, eucalyptus, and cardamom, respectively. The optimum solar radiation for extraction was about 1000 W/m2. Also, oxygen compounds (96.45, 79.640, 42.98, and 83.76%) comprised the main proportion in the clove, cinnamon, eucalyptus, and cardamom essential oils, while orange and lemon essential oils had a high presence of terpenes. Furthermore, essential oils obtained by SEE had a similar yield and alcohol solubility to THD. According to green extraction process analysis, solar energy‐based extraction was 23–34% greener than THD, depending on the type of plant material.Practical ApplicationsThe innovative solar‐based extraction system designed and developed in this research can be used at farms and small factories to obtain essential oils using the zero‐energy concept. From the energy consumption viewpoint, this technology can be regarded as “free process” which can reduce production costs. Also, the unique design of the heating section of this new system prevents overheating of the sample, making this new solar‐based system suitable for the extraction of thermolabile compounds from plant materials. In this sense, obtaining a high‐quality essential oil without running cost (in terms of electricity cost), relatively small size, and low capital cost makes this system practical for future applications.

A modified microwave hydrodistillation and simultaneous extraction in a rotating state to obtain essential oil, rosmarinic acid, and polysaccharides with sucrose stearate as an additive from Perilla frutescens

An improved approach was developed to obtain essential oil, rosmarinic acid, and polysaccharides with sucrose stearate as a green additive from Perilla frutescens (L.) Britt. Leaves using microwave-induced hydrodistillation and simultaneous extraction (MHDE). In this process, we realize the rotation of the material through a rotary motor so that the material is uniformly irradiated by microwaves. The influencing factors on MHDE were systematically optimized by single factor and central composite design. Under the obtained optimization conditions, the yields of essential oil, rosmarinic acid, and polysaccharides were 0.64% ± 0.03%, 0.18% ± 0.01%, and 4.35% ± 0.19%, respectively. GC-MS analysis results showed that the main component of essential oil prepared by MHDE was perillaldehyde, which accounted for 51.91% of the total essential oil, followed by caryophyllene, accounting for 15.79%. However, the ratio of perillaldehyde in the essential oil obtained by traditional hydrodistillation and extraction (HDE) was only 40.69%, and the proportion of caryophyllene was only 12.50%. MHDE uses sucrose stearate with a long hydrocarbon chain structure as an additive, which reduces the nonterpene aliphatics in the obtained essential oil.

Dual‐cooled microwave extraction of Foeniculum vulgare essential oil and its chemical composition and antibacterial activity: Comparison with hydrodistillation and conventional microwave

AbstractNumerous studies indicate that the efficiency of microwave extraction, a popular method for extracting essential oil, needs to be improved. In this study, we used fennel (Foeniculum vulgare) as the focused species, extracted its essential oil using three methods, including traditional hydrodistillation (HD), single‐cooled microwave extraction (SCME) and dual‐cooled microwave extraction (DCME), and then tested the chemical composition and antibacterial activity of the essential oils. The optimum parameters of DCME were liquid‐solid ratio 5.6 mL/g, extraction time 27 min and irradiation power 600 W. The yield of fennel essential oil raised to 1.172%. The composition of essential oils obtained by both SCME and DCME was obviously different from that obtained by HD, such as higher monoterpene hydrocarbons in SCME and higher oxygenated monoterpenes in DCME. Furthermore, Salmonella Typhimurium and Escherichia coli were the most sensitive to fennel essential oil, followed by Staphylococcus aureus and Listeria monocytogenes. The activity of essential oil from different methods against four bacteria strains was similar. Our founding revealed that the improved microwave extraction greatly raised the yield of fennel essential oil, retained its fragrance and antibacterial activity. Overall, this study provides a theoretical basis for the separation and application of essential oils from natural aromatic plants.

A Review of SEM Characterization for Essential Oils

Not only in hospitals, but also in our homes, plant essentials have been used as therapy. We can see diffusers being utilised in the home and business, and they just require a few drops of essential oil. The aromatherapy might help the person relax. Many essential oils, such as lemongrass, orange, lemon, and rose, can be observed because their aromatic compounds can help individuals relax and quiet down. Plant essential oils can also be utilised to treat inflammation, infections, and cancer. Traditional hydrodistillation is the most common method for extracting essential oils, but it takes time and energy. As a result, different techniques have been adopted, such as microwave assisted extraction. Scanning electron microscopy was used to characterise essential oils in this work (SEM).

Spilanthol-rich essential oil obtained by microwave-assisted extraction from Acmella oleracea (L.) R.K. Jansen and its nanoemulsion: Insecticidal, cytotoxic and anti-inflammatory activities

Acmella oleracea (L.) R.K. Jansen, also named jambù, is an edible and medicinal plant native to Brazil but extensively cultivated all over the world due to its diverse utilizations in food, cosmetics, pharmaceutics, and pest management science. Most of applications are related to the presence of active ingredients, namely alkylamides, among which spilanthol is the most important one. On the other hand, the plant biomass resulting from the large-scale cultivation of A. oleracea may yield an essential oil (EO), which can be used for some industrial purposes, for instance as larvicide against vector mosquitoes. This EO is mainly characterized by mono- and sesquiterpenes, however also spilanthol can be detected in the mixture. To maximize the content of spilanthol in the A. oleracea EO, A. oleracea aerial parts obtained from a cultivation in central Italy were subjected to microwave-assisted extraction (MAE). This procedure allowed to obtain a higher yield and spilanthol content when compared with traditional hydrodistillation (0.47 v 0.22 %, and 13.31 vs 2.24 %, respectively). The EO terpene fraction was mainly represented by β-pinene (10.8 %), myrcene (12.3 %), (E)-caryophyllene (19.4 %) and α-humulene (1.1 %). The A. oleracea EO was encapsulated into a nanoemulsion (NE) containing 6 % EO using a high-energy method. The formulation physical stability was assessed by optical microscope and DLS analyses at different timepoints showing stability up to one year of storage. The A. oleracea EO and its NE, along with the isolated spilanthol, were evaluated for acute toxicity against the 3rd instar larvae of Culex quinquefasciatus, a filariasis and arbovirus vector of public health importance, achieving LC50 values of 16.1, 407.5, and 3.1 μL/L, respectively. The larvicidal activity seemed to be not dependent on the interaction with the cholinergic system, as shown by the high IC50 values of A. oleracea EO and spilanthol exhibited in the anti-acetylcholinesterase (AChE) assay. Testing LC30 values, the A. oleracea-borne products showed a significant impact on larval development, fecundity, fertility and natality of C. quinquefasciatus. Testing LC30 values, the A. oleracea EO-NE provided a higher efficacy than spilanthol, reducing the adult fertility, in terms of egg hatchability (%) and the overall abundance of F1 larvae. These results can be considered as promising for the development of new mosquito larvicides. The safety use of A. oleracea EO, NE and spilanthol was demonstrated in assays on mammalian fibroblasts and microglia cells, showing low level of cytotoxicity coupled with protective effects against inflammation.

Microwave-assisted hydrodistillation of essential oil from fennel seeds: Optimization using Plackett–Burman design and response surface methodology

The study aims to optimize the microwave-assisted hydrodistillation (MAHD) of Foeniculum vulgare seed essential oil (FSEO), for the purposes of maximizing efficiency and reducing costs in terms of time and energy. Plackett–Burman design (PBD) was investigated to screen the six different variables affecting FSEO extraction and select the most significant ones. Response Surface Methodology (RSM) was used to evaluate the interactions of the significant parameters and to determine optimal conditions. MAHD and the traditional hydrodistillation (HD) techniques were compared in terms of extraction efficiency, economic and environmental impacts, and chemical composition of the FSEO. The optimum conditions of the studied responses were particle size less than 333.4673 μm, at the irradiation time of 20 min and a microwave power of 305.9282 W with a solid-liquid ratio of 0.1477 g/mL. Gas Chromatography (GC) analysis showed that the FSEO composition in MAHD and HD is similar with slight differences. Therefore, the results show that the microwave-assisted hydrodistillation method is an innovative, economical and environmentally friendly approach to efficiently and safely extract essential oil an economic and green innovative approach to extract efficiently and safely the essential oil (EO).

Hydrodistillation extraction, GC-MS analysis and biological activities of Thymus vulgaris and Mentha arvensis essential oil

The purpose of the study was to examine the chemical composition, antibacterial and antioxidant capabilities of Thymus vulgaris and Mentha arvensis essential oils. The essential oils were extracted using the traditional hydrodistillation process and evaluated using GC-MS. Thymus is a genus of valuable medicinal herbs that are highly recommended owing to the therapeutic effects of its essential oils, which are often known as thyme oil. The essential oils of Thymus vulgaris were tested for phytochemical activity and scientific support of traditional usage. Gas chromatography and mass spectrometry (GC-M) were used to examine the hydrodistillated oil produced from wild thyme species. Forty-seven components were identified. Among those thymol (60.55%), terpinene (8.53%), p-cymene (9.48%) and carvacrol (3.35%) were the major constituents. Other components were present in less than 2% of the total. Gas chromatography and mass spectrometry (GC-MS) were used to identify the components in Mentha arvensis essential oil. The essential oil study resulted in the discovery of twenty-eight compounds, accounting for 92.85% of the oil compositions. Menthone (29.42 percent), Menthol (21.35 percent), Isomenthone (10.85 percent), Eucalyptol (6.95 percent), neo-Menthol (4.75 percent), cis-Piperitone oxide (3.63 percent), Linalool (2.22 percent), Thymol (1.64 percent), Dl-Limonene (1.48 percent), and -Phellandrene (3.22 percent) were just the major components. Thymus vulgaris was investigated for antimicrobial activity against seven common food-borne bacteria and fungi: Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, and Candida albicans using disc diffusion method. Thyme oil showed positive results against each pathogen. Antibacterial activity of Mentha arvensis was analyzed against six bacteria: Using the micro wells approach, Candida albicans (C. albicans), Pseudomonas aeruginosa (Ps. aeruginosa), Proteus mirabilis (P. mirabilis), Enterococcus faecium (E. faecium), Escherichia coli (E. coli), and Staphylococcus aureus (St. aureus) were employed. Essential oil gave positive results against each bacterium. The essential oil of Mentha arvensis was tested for antifungal efficacy against Candida flexuosus. At all concentrations, essential oil proved effective against F. solani. The antioxidant activity of thyme essential oil was determined using the DPPH test. Results showed, antioxidant activity is directly proportional to phenolic content.