Microwave-assisted Hydrodistillation Research Articles

Ultrasonic Pretreatment Combined with Microwave-Assisted Hydrodistillation for Extraction of Essential Oil from Melaleuca bracteata ‘Revolution Gold’ Leaves Scales Induced by Cellulase-Inorganic Salt and Its Anti-Fungal Activity

In order to further develop the commercial use of Melaleuca bracteata (F. Muell), this report studied the extraction of essential oil from Melaleuca bracteata (F. Muell) leaves using ultrasonic pretreatment, cellulase-inorganic salt soaked and combined with microwave-assisted hydrodistillation. To optimize the primary contributing parameters, the Box–Behnken design (BBD) was applied. The optimum yield of essential oil was 9.61 mL/kg DW at a microwave power of 510.77 W, lithium chloride dose of 63.56 μmol, and microwave irradiation period of 46.97 min. The essential oil included a total of 41 compounds, and methyl eugenol (76.53%) and methyl cinnamate (12.62%) were the main compounds. The inhibitory impact was notable when the essential oil concentration was 1.6 mg/mL. Therefore, it has the potential to replace chemical pesticides. When the concentration of the essential oil solution was 1.6 mg/mL, the three pathogenic species of fungus (Pseudocercospora psidii, Colletotrichum eriobotryae, and Colletotrichum siamense) were greatly affected; at this dose, the fungus was unable to develop and its growth diameter was 0 mm. Additionally, the fungus’s inhibition rate reached 100%.

PROFILING OF SEIZED CANNABIS SATIVA L. FLOWERING TOPS BY MEANS OF MICROWAVE-ASSISTED HYDRO DISTILLATION AND GAS CHROMATOGRAPHY ANALYSES

This research aimed to support police forces in their battle against illicit drug trafficking by means of a multi-technique approach, based on gas chromatography. In detail, this study was focused on the profiling of volatile substances in narcotic Cannabis sativa L. flowering tops. For this purpose, the Scientific Investigation Department, RIS Carabinieri of Messina, provided 25 seized samples of Cannabis sativa L. The content of Δ9-tetrahydrocannabinol (THC), useful to classify cannabis plant as hemp (≤ 0.2%) or as marijuana (> 0.2%), was investigated. Essential oils of illicit drug samples were extracted using a microwave-assisted hydro-distillation (MAHD) system; GC-MS and GC-FID analytical techniques were used for the characterization of the terpenes and terpenoids fingerprint. Furthermore, the enantiomeric and carbon isotopic ratios of selected chiral compounds were investigated using a heart-cutting multidimensional GC (MDGC) approach. The latter exploited a combination of an apolar column in the first dimension, and a chiral cyclodextrin-based column in the second one, prior to parallel carbon isotope-ratio mass spectrometry (C-IRMS) and MS detection. Finally, all the data were gathered into a statistical model, to demonstrate the existence of useful parameters to be used for the classification of seized samples.

Essential Oil of Glycosmis stenocarpa (Drake) Leaves Grown in Hai Duong Province, Vietnam

In this study, the extraction of essential oil of Vietnamese Glycosmis stenocarpa leaves was conducted using two different methods such as conventional microwave-assisted hydrodistillation (MAHD) and hydrodistillation (HD). The obtained products were analyzed by gas chromatography-mass spectrometry (GC-MS). The essential oil quality was attained in a comparable manner in both samples respectively. In addition, the GC-MS analysis showed that the hydrodistillation essential oil contains a total of 29 chemical compounds, whereas the MAHD essential oil contained 28 constituents. Moreover, the chemical constitutes of the two essential oils were similar, with the major components being citronellal, neryl acetate, citronellyl acetate and geranyl acetate.

Exploring the essence of celery seeds (Apium graveolens L.): Innovations in microwave-assisted hydrodistillation for essential oil extraction using in vitro, in vivo and in silico studies

This study presents the composition analysis of essential oils extracted from celery seeds (Apium graveolens L.) collected from Morocco. Essential oil of A. graveolens (AG-EO), were obtained through microwave-assisted hydro-distillation, and its composition was characterized using gas chromatography/mass spectrometry (GC/MS). antimicrobial properties were assessed utilizing disc diffusion and microdilution assay methods, while antioxidant activities were evaluated through spectrophotometric techniques. Additionally, in vivo anti-inflammatory effects were investigated. The molecular docking technique, a computational approach utilized to predict the binding of small molecules to specific proteins, was employed to elucidate the antioxidative and antibacterial characteristics of the constituent molecules. The physicochemical and pharmacokinetic features of absorption, distribution, metabolism, excretion, and toxicity (ADME-Tox) tests were anticipated to provide insights into the drug likeness, pharmacokinetic characteristics, and expected safety profiles upon ingestion and the potential pharmacological activity of the identified compounds. Fifteen constituent compounds representing 99.99% of AG-EO were identified and quantified by the use of GC/MS. The main constituent, comprising 64.58% of AG-EO was limonene. AG-EO demonstrated a significant DPPH free radical scavenging activity, showing estimated scavenging rates of 8.49±0.00 µg/mL, and 5.09±0.04 µg/mL for ABTS+. AG-EO exhibited reducing Power (RP) and total antioxidant activity (TAC) of 3.42±0.01 µg/mL and 245.93±0.04 mg AAE/mL, respectively. AG-EO exhibited significant antimicrobial activity against all tested microorganisms. Additionally, the anti-inflammatory activity demonstrated the remarkable efficacy of AG-EO. Taken together, the essential oil derived from celery seeds holds promise for large-scale utilization as an environmentally friendly preservative within the food and agriculture industries, effectively countering fungal growth and aflatoxin contamination in stored commodities. Additionally, it exhibits potential as a suitable candidate for the development of pharmaceutical drugs.

Ionic liquid microwave-assisted hydrodistillation extraction of Angelica sinensis essential oil and its own anti-inflammatory and antioxidant activities

In this study, ionic liquid microwave-assisted hydrodistillation (IL-MAHD) was employed to overcome the challenges of substantial emulsification and low extraction yield which occur in the extraction process of Angelica sinensis essential oil (AEO). Additionally, an online detection system was introduced into the AEO extractor to enable real-time monitoring during the extraction process. Optimal conditions were determined as follows: material-to-liquid of 1:10, ionic liquid concentration of 0.5%, microwave power of 400 W, extraction time of 4 h, condensation temperature of 20 °C, and cooling temperature of 40 °C. Under these optimized conditions, the AEO yield reached 0.7707%, marking a 1.4066-fold increase compared to microwave-assisted hydrodistillation (MAHD) and a 3.7615-fold increase compared to hydrodistillation (HD). Meanwhile, IL-MAHD exhibited the highest relative content of (Z)-ligustilide (73.424%), and the corresponding AEO displayed significant anti-inflammatory and antioxidant effects at concentrations of 7.8125, 15.625, and 31.25 µg/g. The results of extraction kinetics and online monitoring suggested that the IL-MAHD achieved the fastest extraction yield of AEO. This study provides a new perspective on exploring a potential cost-efficient technology for the industrial extraction of essential oils.

Ultrasonic pretreatment combined with microwave-assisted hydrodistillation for the situ extraction of essential oil from Pinus koraiensis seed scales induced by tea saponin: Functional activity, composition, thermal stability and material characterization

In this work, in situ extraction of essential oil from Pinus koraiensis seed scales using tea saponin-induced ultrasonic pretreatment-microwave-assisted hydrodistillation (UP-MAHD) was studied. By fitting the extraction kinetic curves with different factors, a first-order kinetic model was determined to be more suitable. The key factors were screened and optimized via PlackettBurman Design (PBD) and BOX-Behnken Design (BBD). Under the optimization parameters of a liquid material ratio of 14 mL/g, power of 100 W, time of 15 min, temperature of 50 °C, and tea saponin dose of 0.4% for the ultrasonication and then microwave at 458 W for 18 min, the actual yield was 8.02 μL/g± 0.35% and was highly consistent with the theoretical yield of 8.21 μL/g. UP-MAHD-treated Pinus koraiensis seed scales essential oil (PKSSEO) had good inhibition functional activity of α-amylase. In addition, the chemical composition of the PKSSEO were determined using Gas chromatographymass spectrometry (GCMS) and Fourier transform infrared spectroscopy (FT IR), thermal gravimetry (TG), and differential scanning calorimetry (DSC), and its spatial structure characterization (SSC) obtained via UP-MAHD treatment was enhanced. In summary, this extraction method efficiently extracted PKSSEO with a lower effect on its activity and composition and could have solid future development prospects. Our study provided effective theoretical data support for the reuse and development of abandoned Pinus koraiensis seed scales resources.

Essential oil was extraction from Cinnamomum camphor peel using microwave as an aid and study of their inhibitory effect on Pseudocercospora psidii fungi

To apply the natural ingredients of plants in the field of food preservation, the essential oil of Cinnamomum camphor peel was isolated by salt-out pretreatment and microwave-assisted hydrodistillation. Using the single-factor mixed response surface approach, the extraction yield was optimized. A total of 14.98 mL/kg DW (dry weight: DW) was the greatest essential oil yield recorded. By using GC–MS analysis, a total of 29 compounds were found in the essential oil, with methyl eugenol (12.66 %) and safrole (10.36 %) being the two predominant compounds. However, the essential oil had a clear inhibitory effect on Pseudocercospora psidii at a concentration of 10 mg/mL. In conclusion, Cinnamomum camphora pericarp essential oil is anticipated to be a green natural pesticide that significantly inhibits pathogenic bacteria in crops.

The Flavor Characterization of ‘Huyou’ (Citrus changshanensis) Essential Oils Extracted by Conventional and Novel Methods

The aroma of citrus is among the most appealing natural flavors. ‘Huyou’ (HY) is a hybrid citrus with a unique flavor compared to grapefruit (GF), but few studies have analyzed its characteristic flavor comprehensively. In this study, we extract six essential oils (EOs) from HY and GF peels by cold pressing (CP) and microwave-assisted hydrodistillation (MADH) and spinning cone column (SCC). Further, the flavor of six EOs was investigated by using flavoromics analysis, including e-nose, GC-MS and GC-O combined with chemometric approaches. The results showed that CP EOs exhibited a stronger citrus characteristic flavor, while MADH and SCC EOs contained more diverse volatiles. A total of 23 key odorants were identified in the GC-O-MS analysis, 12 of which were specific to HY. The flavor wheel and partial least squares regression (PLSR) revealed that floral, sweet and fruity odors were positively correlated with linalool, α-terpineol and geraniol, while fatty, green and woody odors with germacrene D, germacrene B and nootkatone. Additionally, based on orthogonal partial least squares discriminant analysis (OPLS-DA), six aroma-active compounds were screened as aroma markers to distinguish HY from GF; i.e., γ-terpinene, D-limonene, germacrene D, nootkatone, germacrene B and terpinolene. The extraction methods and citrus varieties both impact the flavor characterization of citrus EOs, and our study provides guidance on the extraction and application for citrus EOs.

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.

A comprehensive review of Patchouli plant: Comparison of microwave-assisted hydro-distillation and hydro-distillation methods

A comprehensive review of Patchouli plant: Comparison of microwave-assisted hydro-distillation and hydro-distillation methods

Steps to achieve carvone-rich spearmint (Mentha spicata L.) essential oil: a case study on the use of different distillation methods.

Spearmint essential oil is a valuable medical and food product. Spearmint essential oil is effective for the treatment of flatulence, indigestion, nausea, and colic along with Alzheimer, obesity, and fungal infections. This study evaluated the quality and quantity of spearmint essential oil by examining some extraction strategies. The procedures were hydro-distillation, hydro-steam distillation, microwave-assisted hydro-distillation, and open hydro-distillation. The hydro-distillation had five pH levels (2, 4, 6, 8, and 10) and four NaCl concentrations (0.5, 1, 1.5, and 2%). microwave-assisted hydro-distillation at a power of 225 W was applied for 60, 90, and 120 minutes for process durations. The solvent extraction of herbal distillate obtained by an open hydro-distillation system was done using n-pentane and n-hexane to achieve a recovered essential oil by a rotary evaporator. The results showed that the lowest pH in the hydro-distillation process led to obtaining double yield compared to the control. Additionally, at 1 and 1.5% NaCl concentrations, the oil yield increased by 12.86 and 20.87%, respectively. Although the yield was reduced by microwave-assisted hydro-distillation, however within 120 minutes, carvone increased by 12.7% and limonene decreased by 42.3%. The best quality of spearmint oil belonged to solvent extraction followed by rotary evaporator.

Recent Development on the Extraction Process of Plants Essential Oil and its Effect on Chemical Composition: A Review

This study presents a thorough review on different innovative extraction techniques of different plant essential oil derived from its peel, leaves, seeds and shrubs. The review also entails the different pre-treatment processes that affects the quality and recovery of the plant essential oil. Also, discussed the recently developed green extraction method such as Microwave Assisted Hydrodistillation (MAHD), Solvent Free Microwave Extraction (SFME), Ultrasound Assisted Extraction (UAE), Supercritical Fluid Extraction (SFE) and Ohmic Heated Assisted Hydrodistillation (OHAD). The impact of these extraction process on the important chemical composition of essential oil is further analyzed in this review. The important parameters in extraction is also studied such as the water to material ratio, extraction temperature, power input and extraction time. Based on the different articles reviewed, it signifies that the innovative extraction method improves the quality and quantity of the essential oil yield. It also improved the number of component that can be extracted in the plant essential oil and its biological activities such as antioxidant and antimicrobial activities. Thus this review aims to emphasize the potential of the newly developed essential oil extraction techniques that would help to boon the pharmaceuticals, food and agriculture industry.

Investigation of Antioxidant and Antibacterial Effect of Chemical Compounds Cardamine uliginosa Plant

Background & Aims: Brassicaceae is a medium-sized family of flowering plants. The family contains more than 327 genera. Cardamine uliginosa is a type of plant of this species. Chemical and biochemical findings of this genus are very limited. This study aimed to investigate the chemical compounds and antioxidant and antibacterial properties of C. uliginosa. Materials and Methods: Essential oil was prepared by hydrodistillation method and microwave assisted hydrodistillation (MAHD). The chemical composition of essential oil was evaluated by GC and GC-MS methods. The antioxidant property of the hydroalcoholic extract was investigated by 2, 2-dipheny1-1-picrylhydrazyl (DPPH) solution. Finally, the antibacterial activity of C. uliginosa was investigated using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. Results: Phetalic acid, Phenil, Caryophyllene, Eicosane, and other chemical compounds were found in the essential oil of C. uliginosa. The half maximum inhibitory concentration (IC50) of hydroalcoholic extract was 0.42 µg/mL. The MIC and the MBC against both Escherichia coli and Staphylococcus aureus were 15.62 and 31.25 respectively. The major compounds in the essential oils were 3-methyl-4-isopropylphenol (15.20%) and 1, 2-benzenedicarboxylic acid (16.75%). Conclusion: Considering the chemical compounds of C. uliginosa and the finding of the antibacterial and antioxidant activity of C. uliginosa in vitro, capability of this plant needs to be further investigated for use in health and medical industries.

Antioxidant Properties and Secondary Metabolites Profile of Hyptis colombiana at Various Phenological Stages.

Hyptis colombiana (Lamiaceae family), a species also treated as Cantinoa colombiana in a recently segregated genus from Hyptis, is a perennial herb or subshrub native to the Andes of northern South America. H. colombiana leaves are commonly used in traditional medicine to treat respiratory and digestive illnesses. In this study, H. colombiana plants at different phenological stages (vegetative, flowering, and post-flowering) were harvested to obtain essential oils (EOs) and extracts (from fresh plant materials or post-distillation waste) whose chemical compositions and antioxidant activities were determined. H. colombiana EOs distilled by microwave-assisted hydrodistillation were analyzed by GC/MS/FID, and hydroalcoholic extracts obtained from fresh plant materials or post-distillation waste were analyzed by UHPLC-ESI+/--Orbitrap-MS. The antioxidant activity was evaluated by the ABTS+• and ORAC assays. The principal compounds found in EOs were sesquiterpene hydrocarbons (65%); specifically, (E)-β-caryophyllene and germacrene D. Pyranone, rosmarinic acid, rutin, and p-hydroxybenzoic acid were the main constituents in H. colombiana extracts. After analyzing the chemical composition and antioxidant activity (ORAC) of EOs and hydroethanolic extracts from flowering H. colombiana plants, minimal variations were found. It is advisable to harvest H. colombiana plants during their flowering stage to acquire EOs and extracts that can be utilized in the agro-industry of EOs and their natural derivatives.

Enhancing the Extraction Process Efficiency of Thyme Essential Oil by Combined Ultrasound and Microwave Techniques

In this paper, the essential oil (EO) extraction from thyme by the consecutive use of ultrasound and microwave treatments is presented. The aim of this study was to apply an ultrasound pre-treatment of thyme leaves to enhance the thymol content and the extraction yield of the EO obtained by microwave-assisted hydro-distillation (MWHD). Compared with conventional hydro-distillation (CHD), the consecutive use of ultrasound pre-treatment and microwave extraction resulted in a 72% lower extraction time. When the ultrasound pre-treatment (using the ultrasonic processor with an amplitude of 70%) was applied, the EO content was 23% higher compared to the extraction without pre-treatment (2.67 ± 0.06 g EO/100 g DM for the MWHD with ultrasound pre-treatment compared with 2.18 ± 0.07 g EO/100 g DM for the MWHD without pre-treatment). The EO samples were analyzed by GC/MS. The results showed that the major component, thymol, varied from 43.54% (by CHD) to 65.94% (by the consecutive use of ultrasound and microwave treatments).

Comparative study of the chemical composition and the antioxidant, antidiabetic, anti-inflammatory and cytotoxic activities of Citrus aurantium essential oils extracted by conventional hydrodistillation and microwave-assisted hydrodistillation methods from Algeria

This study aims to evaluate the antidiabetic, anti-inflammatory, cytotoxic, and antioxidant properties of essential oils obtained from the peels of Citrus aurantium and extracted with MAHD and HD. The various compounds detected include limonene and linalol. In this context, we used the methods of bovine serum albumin anti-denaturation to evaluate the anti-inflammatory property and glucose uptake by yeast cells to evaluate the antidiabeticone. The results of evaluating the antidiabetic and the anti-inflammatory activities indicate that the essential oil extracted by MAHD has greater efficiency compared to the essential oil extracted by HD. Besides, the antioxidant potential of the essential oil was evaluated using the DPPH free radical scavenging, reducing power, and β-carotene/linoleic acid tests. Results show that the essential oil extracted by HD presents a high antioxidant activity. Moreover, essential oil is a potential source of important bioactive compounds and of possible synergistic effects among its components. To support the phytochemical analysis, an attempt was made to identify some potential compounds from Citrus aurantium essential oils that can inhibit important drug targets like bovine serum albumin (BSA), cyclooxygenase-2 (COX-2), and tubulin using molecular docking and molecular dynamics simulation methods.

Microwave Assisted Hydrodistillation Essential Oil from Lime Peel Waste as Aromatherapy Candles

Flavonoids belong to the extensive group of polyphenol compounds. They can function as antioxidants and antibacterials by denaturing bacterial cell proteins and damaging bacterial cells. One source of essential oils is lime peel, which is often discarded and goes unused. The distillation method utilizes microwaves, offering an alternative to conventional distillation techniques and resulting in enhanced effectiveness and efficiency. The Microwave Assisted Hydrodistillation (MAHD) method proves to be more energy-efficient, environmentally friendly, rapid, safe, and cost-effective. This study aims to assess the impact of the MAHD method on the quantity and quality of essential oils extracted from lime peels. Laboratory tests are conducted in accordance with Indonesian national standards. The overarching objective is to establish a process that transforms discarded lime peels into aromatherapy candles, contributing to respiratory health. The MAHD method is employed with a sample mass to distilled water solvent ratio of 1:1. The resulting essential oil undergoes analysis using the GC-MS method. According to the GC-MS test results, the compound with the highest percentage area is limonene at 98%. This is followed by trans-caryophyllene at 99% with a retention time of 12.422, and beta-selinene at 99% with a retention time of 13.191.

Extraction of Java Lemongrass (Cymbopogon citratus) Using Microwave-Assisted Hydro Distillation in Pilot Scale: Parametric Study and Modelling

This study aims to extract oil from Java lemongrass (Cymbopogon citratus) using the pilot-scale Microwave-Assisted Hydro distillation method (distiller volume 10,000 mL). The operating variables of this research are the extraction time, the microwave power, and the ratio of the mass of the material to the solvent (F/S ratio). The results showed an increase in the yield of lemongrass oil along with the increase in extraction time using the Microwave-Assisted Hydro distillation (MAHD) method, and this trend will continue to occur as microwave heating is selective and volumetric. Thus, there is a tendency to increase yield with increasing power. In general, it follows that the higher the power, the higher the yield. The energy received by the material to be converted into heat has caused the essential oil yield to be more abundant, with the highest yield being obtained at 800 W. The increase in the material to solvent ratio increased the oil yield up to a certain point. However, the yield started declining after the F/S ratio of 0.08 was reached. The first order kinetic model well represents the extraction process at a pilot scale. The pilot scale's oil yield is slightly lower than the laboratory scale MAHD. Compositional analysis of the result suggests that the main components of Java lemongrass oil are Geranial (30.06%), Z-Citral (25.88%), Eugenol (12.88%), and Beta-Myrcene (12.84%).

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.

Methodology for Extraction of Essential Oils: A Review

The majority of concentrated and volatile Essential oils are extracted from various parts of the plants. Essential oils contain hundreds of organic constituents such as natural elements, vitamins, hormones, etc., widely used in the perfumery and pharmaceutical industries. Different techniques are available for the extraction of essential oil, such as hydro and steam distillation, cold pressing/expression, Maceration, solvent extraction, Effleurage, Carbon Dioxide Extraction, Hydro Diffusion, etc., and innovative techniques like Supercritical Fluid Extraction (S.F.E.), Microwave Assisted Hydro distillation (MAHD), Ultrasound-Assisted Extraction (U.A.E.), Solvent-free Microwave Extraction (SFME), Microwave hydro diffusion and Gravity (M.H.G.). This review paper summarizes the research on various methods for essential oil extraction for various raw materials. The summary of this paper included information on different plant materials, the most suitable extraction method with operating conditions, advantages, and disadvantages of extraction methods, etc.