Microwave accelerated steam distillation of essential oil from lavender: A rapid, clean and environmentally friendly approach

A new process design and operation for microwave accelerated steam distillation (MASD) of essential oils was developed. A packed bed of lavender flowers (Lavandula angustifolia Mill., Lamiaceae) sits above the steam source generated by microwave heating. Only steam passes through it without the boiling water mixing with vegetable raw material, as is the case in hydro-distillation. MASD has been compared with a conventional technique, steam distillation (SD), for the extraction of essential oil from lavender flowers. Extraction of essential oils from lavender with MASD was better than SD in terms of energy saving, rapidity (10 min versus 90 min), product yield, cleanliness and product quality.     

Solvent-free microwave extraction of essential oil from aromatic herbs: comparison with conventional hydro-distillation

Solvent-free microwave extraction (SFME) is a combination of microwave heating and dry distillation, performed at atmospheric pressure without added any solvent or water. Isolation and concentration of volatile compounds are performed by a single stage. SFME has been compared with a conventional technique, hydro-distillation (HD), for the extraction of essential oil from three aromatic herbs: basil (Ocimum basilicum L.), garden mint (Mentha crispa L.), and thyme (Thymus vulgaris L.). The essential oils extracted by SFME for 30min were quantitatively (yield) and qualitatively (aromatic profile) similar to those obtained by conventional hydro-distillation for 4.5 h. The SFME method yields an essential oil with higher amounts of more valuable oxygenated compounds, and allows substantial savings of costs, in terms of time, energy and plant material. SFME is a green technology and appears as a good alternative for the extraction of essential oils from aromatic plants.     

Cupressus arizonica fruit essential oil: A novel green inhibitor for acid corrosion of carbon steel

Natural-based corrosion inhibitors have gained great research interest thanks to their low cost and higher performance. The Cupressus arizonica fruit essential oil (CAFEO) has a higher extraction yield than leaves; however, it has less antibacterial and antifungal activities. The three main components in the CAFEO were α-pinene (51.07%), myrcene (17.92%), and limonene (9.66%). Essential oils with a higher percentage of α-pinene were found to have outstanding corrosion inhibition properties. Therefore, herein, the CAFEO was investigated as a green corrosion inhibitor for carbon steel (CS) in 1.0 mol/L HCl using electrochemical, i.e., potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), and scanning electron microscope (SEM) techniques. The experimental results revealed that CAFEO successfully inhibited the carbon steel corrosion in 1.0 mol/L HCl solution. Results from PDP indicated that the inhibitor had a mixed-type effect with a predominance cathodic character. EIS data showed that the charge transfer resistance of the CS electrode increased from 20.9 Ω cm² in blank solution to 294.5 Ω cm² in HCl solution inhibited with 0.5 g/L of CAFEO at 298 K, leading to a significant decrease in the double layer capacitance values and an inhibition efficiency (η%) of 93%. The high temperatures showed a negative effect on the corrosion inhibition efficiency of the tested inhibitor. At 323 K, the η% of CAFEO decreased to 77%. Besides, SEM images showed that the inhibitor formed a protective barrier against acid attack, preventing carbon steel from corrosion. Theoretical calculations by Density Functional Theory (DFT) were performed to investigate the reactivity of the three main components of CAFEO.     

Water as a green solvent combined with different techniques for extraction of essential oil from lavender flowers

Using water as a green solvent with a variable geometry makes use of physical and chemical phenomena that are fundamentally different from those applied in conventional extraction techniques such as hydro-distillation, steam distillation or solvent extraction. Advantages and drawbacks of using water as a solvent with different physical and chemical states have been compared. A total of ten extraction techniques: hydro-distillation (HD), steam distillation (SD), turbo-hydro-distillation (THD), salt-hydro-distillation (NaCL-HD), enzyme-hydro-distillation (Enzyme-HD), micelle-hydro-distillation (Micelle-HD), ultrasound-hydro-distillation (US-HD) or subcritical water-hydro-distillation (SW-HD), solvent-free microwave extraction (SFME) and microwave steam distillation (MSD) were used to extract the essential oil from lavender (Lavandula L.) and their results were compared. The quantity was measured by the yield of essential oil and the quality was evaluated using the oil composition especially the content of linalyl acetate, linalool and terpin-4-ol compared with the corresponding control sample: Hydro-distillation. For environmentally friendly of the process: extraction time, total energy consumption and CO₂ emission were considered and compared with conventional hydro-distillation. The mechanism explaining the linalyl acetate degradation has been resolved by using COSMO-RS software. Based on the present experimental conditions, it is recommended that lavender oil may be produced preferably by steam distillation assisted by microwave extraction to reduce the by-product formation by various chemical reactions and to get better oil recoveries.     

Microwave extraction of essential oils from dried fruits of Illicium verum Hook. f. and Cuminum cyminum L. using ionic liquid as the microwave absorption medium

Ionic liquid was used as microwave absorption medium and applied to the extraction of essential oils from dried fruits of the Illicium verum Hook. f. and Cuminum cyminum L. by microwave‐assisted extraction. The extraction time is less than 15 min at the microwave power of 440 W. The constituents of essential oils obtained by the proposed method were compared with those obtained by hydrodistillation. There is no obvious difference in the constituents of essential oils obtained by the two methods.     

Continuous subcritical water extraction of medicinal plant essential oil: comparison with conventional techniques

A subcritical extractor equipped with a three-way inlet valve and an on/off outlet valve has been used for performing subcritical water extractions (SWE) in a continuous manner for the isolation of the essential oil of fennel, a medicinal plant. The target compounds were removed from the aqueous extract by a single extraction with 5 ml hexane, determined by gas-chromatography-flame ionization (GC-FID) and identified by mass spectrometry (MS). The proposed extraction method has been compared with both hydrodistillation and dichloromethane manual extraction. Better results have been obtained with the proposed method in terms of rapidity, efficiency, cleanliness and possibility of manipulating the composition of the extract.     

Rapid determination of essential oil compounds in Artemisia Selengensis Turcz by gas chromatography-mass spectrometry with microwave distillation and simultaneous solid-phase microextraction

In the work, for the first time, two solvent-free sample preparation techniques of microwave distillation (MD) and solid-phase microextraction (SPME) were combined, and developed for determination of essential oil compounds in traditional Chinese medicine (TCM). Using the proposed method, isolation, extraction and concentration of TCM essential oil compounds can be carried out in a single step. To demonstrate its feasibility, MD-SPME was compared with a conventional technique, steam distillation (SD), for gas chromatography-mass spectrometry (GC-MS) analysis of essential oil compounds in a TCM, Artemisia Selengensis Turcz. Forty-nine compounds in the TCM were separated and identified by the present method, while only 26 compounds were detected by SD method. Relative standard deviation (R.S.D.) values less than 9% show that the present method has good precision. The SD method required long time (6 h) to isolate of the essential oil, and large amount of organic solvent for further extraction, while MD-SPME needed little time (only 3 min) to prepare sample, and no organic solvent. These results show that MD-SPME-GC-MS is a simple, rapid and solvent-free method for determination of TCM essential oil.     

超临界萃取川芎精油的GC-MS分析

不同压力和温度条件下超临界萃取所得川芎精油的收率不同,通过气相色谱-质谱联用对精油的挥发性成分进行分析,结果表明不同条件下超临界萃取所得川芎精油的主要挥发性成分相似,但其质量分数有一些差别.     

Eco-friendly and cleaner process for isolation of essential oil using microwave energy: Experimental and theoretical study

Microwave steam diffusion (MSD) was developed as a cleaner and new process design and operation for isolation of essentials oils and was compared to conventional steam diffusion (SD). The essential oils extracted by MSD for 3 min were quantitatively (yield) and qualitatively (aromatic profile) similar to those obtained by conventional steam diffusion for 20 min. In addition, an optimal operating steam flow rate of 25 g min⁻¹ and microwave power 200 W were found to ensure complete extraction yield with reduced extraction time. To confirm the efficiency of this process a mathematical model was proposed to describe the mass transfer of essential oil from lavender. Solid-steam mass transfer coefficients obtained by MSD were six times higher than obtained by SD. Scanning electronic microscopy was used to confirm the extraction mechanism of the essential oil present in the glandular trichomes of the flowers from lavender outer surface. MSD was better than SD in terms of energy saving, cleanliness and reduced waste water.     

杭白菊和杭黄菊挥发油的GC-MS分析

通过气相色谱-质谱联用仪检测杭白菊和杭黄菊的挥发油化学成分,分别从杭白菊和杭黄菊挥发油中分离鉴定出59种和65种化合物,其主要成分为单萜、倍半萜及其含氧衍生物.     

萃取淫羊藿挥发油的实验与分析

报道了用正交实验法研究超临界萃取淫羊藿挥发性成分的条件;结果显示最佳萃取条件为萃取压力30 MPa,萃取温度40℃,萃取时间1 h。按对结果影响大小依次排列为:萃取压力→萃取温度→萃取时间,在最佳条件下萃取挥发油,收率为2.7%;并用气相色谱-质谱联用技术分析了淫羊藿挥发油的化学成分,从中确认出43种化学成分,用峰面积归一化法通过化学工作站数据处理系统得出各化学成分在挥发油中的质量分数;其中主要成分为薄荷醇、1,2-二甲氧基-4-(2-丙烯基)-苯、5-(1-丙烯基)-1,3-苯并间二氧杂环戊烯、3,5-二甲氧基-甲苯、冰片、十五(碳)烷、1,2,3-三甲氧基-5-甲苯、外-葑醇、2,6,6-三甲基-2,4-环庚二烯-1-酮、2-莰酮等。     

Chemical composition and potential bioactivities of essential oil from Quercus mongolica bark

The chemical composition and potential bioactivities of essential oil from Quercus mongolica bark (EOQMB) were researched for value-added utilization processing by-product. The results of gas chromatography-mass spectrometry (GC–MS) analysis showed that 30 components accounting for 98.42% were identified in EOQMB, with pentadecanoic acid the most abundant compound accounting for 34.90%, which was further confirmed by the Fourier transform infrared observation. EOQMB exerts antioxidant activities, and the IC₅₀ values for scavenging DPPH radical, ABTS radical, and hydroxyl radical were 8.48, 0.77, and 3.54 mg/mL, respectively. The effects of EOQMB on prolonging activated partial thromboplastin time and thrombin time and on decreasing fibrinogen are similar to those of heparin, and the promising anticoagulant activities of EOQMB could be largely contributed by pentadecanoic acid. Herein, the present study uncovered that the waste Q. mongolica bark can serve as a new potential material in pharmaceutical products.     

Chemical composition and larvicidal activity of Algerian Foeniculum vulgare seed essential oil

A laboratory study was conducted to determine the effect of three extraction parameters (soaking time, extraction time and the ratio of solid to liquid) on the yield and chemical composition of Foeniculum vulgare seeds essential oils. The bioactivity of the essential oil extracted for the optimum extraction parameters was assessed against Culex pipiens mosquito. F. vulgare essential oil composition included large amounts of phenylpropanoids. Through an extraction time of 6 h and a ratio solid to liquid of 300 g/L we can get over than 72% of trans-anethol without soaking the seeds. With bioassays, essential oils showed different activities on C. pipiens larvae and pupae. Results show that a concentration at 40 mg/L was sufficient to register 50% mortality for the second instars larvae and this, after 2 h exposition time. Moreover, concentration at 60 mg/L ensured after 4 h exposition time 90% mortality for the fourth instars larvae. However, pupae needed 24 h exposition time to show promising mortalities when using concentration at 200 mg/L. Even if laboratory bioassays are only the first step towards the use of essential oils in practical applications, these substances represent a potential alternative to chemical insecticides in some markets.     

Chemical composition of essential oil from Jordanian Lupinus varius L.

The chemical composition of essential oil obtained by hydrodistillation from flowering shoots of Lupinus varius L. was analyzed by GC–FID and GC–MS. Chemical analysis of this oil showed that it includes a complex mixture of aldehydes, alcohols, esters and mono- and sesquiterpenes. Forty one compounds were characterized in the oil. The major components of the oil were 6,10,14-trimethyl-2-pentadecanone (20.5%), pentadecanal (10.2%), (E) nerolidol (8.43%), carracol ethyl ether (4.3%), α-humulene (3.6%), (2Z,13E)-ocatadeca-2,13-dien-l0-ol (3.2%) and caryophyllene-5-ol (2.7%).     

紫花冷蒿挥发油成分的研究

采用水蒸气蒸馏法提取,运用气相色谱-质谱联用法对香叶蒿挥发油化学成分进行了分析,用气相色谱面积归一化法测定了各成分的质量分数。结果鉴定出72个化合物,主要成分为樟脑(33.136%),桉树脑(23.419%),6-甲基-2-乙烯基-1,3-庚二烯醛(8.414%),孟烯醇(3.819%),桥环萜烯酮(3.276%),莰烯(2.454%),1R-α-蒎烯(1.917%),去甲基丁香酚(1.550%),α-松油醇(1.449%),冰片(1.674%),β-香叶烯(1.165%),百里香酚(0.329%)等。研究表明紫花冷蒿挥发油主要为单萜及其氧化衍生物。其挥发油成分的研究为挖掘其药用及食品香料工业的应用价值提供了科学依据。     

Clean recovery of antioxidant flavonoids from onions: Optimising solvent free microwave extraction method

A solvent free microwave hydrodiffusion and gravity extraction (MHG) of flavonol content from onion (Allium cepa L.) was studied. Effectiveness of this innovative method in extraction of onion total phenolic content, total quercetin (TQ), quercetin aglycon (QA), quercetin-3,4′-diglucoside (QDG), quercetin-4′-monoglucoside (Q4G), quercetin-3-monoglucoside (Q3G), kaempferol (KMF) and myricetin (MRT) have been evaluated and compared with conventional solvent extraction. Microwave extraction offers important advantages like shorter extraction time (23 min), cleaner feature (no solvent or water used) and extraction of valuable onion crude juice retaining fresh organoleptic properties with higher phenolic content (58.29 mg GAE/g DW) at optimized power (500 W). Microwave extraction resulted significant yield (81.5%) with 41.9% of flavonol contents, with better retain of remaining flavonoids (55.9%) in residues of onions. QDG (239.7 mg/100 g DW) and Q4G (82.55 mg/100 g DW) have been reported the main flavonol in this study. Minor quantities of QA (traces), Q3G (4.22 mg/100 g DW) and KMF (3.99 mg/100 g DW) were also detected in microwave onion extracts.     

Ionic liquid-based microwave-assisted extraction of essential oil and biphenyl cyclooctene lignans from Schisandra chinensis Baill fruits

Ionic liquid-based microwave-assisted extraction (ILMAE) has been successfully applied in extracting essential oil and four kinds of biphenyl cyclooctene lignans from Schisandra chinensis Baill. 0.25 M 1-lauryl-3-methylimidazolium bromide ionic liquid is selected as solvent. The optimum parameters of dealing with 25.0 g sample are 385 W irradiation power, 40 min microwave extraction time and 1:12 solid-liquid ratio. The yields of essential oil and lignans are 12.12±0.37 ml/kg and 250.2±38.2 mg/kg under the optimum conditions. The composition of the essential oil extracted by hydro-distillation, steam-distillation and ILMAE is analyzed by GC-MS. With ILMAE method, the energy consumption time has not only been shortened to 40 min (hydro-distillation 3.0 h for extracting essential oil and reflux extraction 4.0 h for extracting lignans, respectively), but also the extraction efficiency has been improved (extraction of lignans and distillation of essential oil at the same time) and reduces the environmental pollution. S. chinensis materials treated by different methods are observed by scanning electronic microscopy. Micrographs provide more evidence to prove that ILMAE is a better and faster method. The experimental results also indicate that ILMAE is a simple and efficient technique for sample preparation.     

Pressurized fluid extraction of essential oil from Lavandula hybrida using a modified supercritical fluid extractor and a central composite design for optimization

Essential oil components were extracted from lavandin (Lavandula hybrida) flowers using pressurized fluid extraction. A central composite design was used to optimize the effective extraction variables. The chemical composition of extracted samples was analyzed by a gas chromatograph-flame ionization detector column. For achieving 100% extraction yield, the temperature, pressure, extraction time, and the solvent flow rate were adjusted at 90.6°C, 63 bar, 30.4 min, and 0.2 mL/min, respectively. The results showed that pressurized fluid extraction is a practical technique for separation of constituents such as 1,8-cineole (8.1%), linalool (34.1%), linalyl acetate (30.5%), and camphor (7.3%) from lavandin to be applied in the food, fragrance, pharmaceutical, and natural biocides industries.     

Microwave hydrodiffusion and gravity, a new technique for extraction of essential oils

A new process design and operation for the extraction of essential oils was developed. Microwave hydrodiffusion and gravity (MHG) is a combination of microwaves for hydrodiffusion of essential oils from the inside to the exterior of biological material and earth gravity to collect and separate. MHG is performed at atmospheric pressure without adding any solvent or water. MHG has been compared with a conventional technique, hydrodistillation (HD), for the extraction of essential oil from two aromatic herbs: spearmint (Mentha spicata L.) and pennyroyal (Mentha pulegium L.) belonging to the Labiatae family. The essential oils extracted by MHG for 15 min were quantitatively (yield) and qualitatively (aromatic profile) similar to those obtained by conventional hydrodistillation for 90 min. MHG also prevents pollution through potential 90% of energy saved which can lead to greenhouse gas emission benefits.     

双花千里光花精油的GC-MS分析

采用气相色谱-质谱联用技术对西藏药用植物双花千里光的花精油进行化学成分分析,共分离出100余个峰,鉴定出其中73个化合物,其含量占精油总量的89％以上。该花精油的成分主要为单萜、倍半萜和脂肪酸及其酯,其中大于2％的成分共有12个,占精油总量的约70％。