Microwave-assisted Distillation Research Articles

Extraction of essential oil from Salvia fruticosa using a newly developed microwave-assisted distillation system for industrial applications

In this study, an industrial-scale microwave-assisted distillation (MWAD) is designed by combining 12 magnetrons with 1 kW, and the essential oil of the S. fruticosa plant is obtained, as a novelty. Also, the effect of microwave (MW) power applied at different times and powers on essential oil yield (%) and energy consumption is experimentally investigated and the statistical analysis using experimental data is carried out using the Design Expert program. For each test, 5 kg of dried plants as an herb are utilized and placed in a 100-L steam boiler. When the results are examined, the proposed MWAD system reduces the distillation time by half compared to the conventional distillation (CD) system. In terms of energy consumption, there is a huge energy saving due to the time being reduced by half. Moreover, compared to the essential oil yield obtained in the CD system, there is an increase in yield (average value of 15%) in the MWAD system. According to the chemical analysis results, no negative effect of MW power on essential oil quality is observed. However, MW power affects the percentage changes of some terpene groups. As a result, the MWAD system can be safely used in industrial distillation processes as an alternative to CD systems due to its high performance and low energy consumption.

Variation of the essential oil components of Citrus aurantium leaves upon using different distillation techniques and evaluation of their antioxidant, antidiabetic, and neuroprotective effect against Alzheimer’s disease

Citrus fruit essential oil is considered one of the widely studied essential oils while its leaves attract less attention although being rich in nearly the same composition as the peel and flowers. The leaves of bitter orange or sour orange (Citrus aurantium L.) were extracted using three different techniques namely; hydrodistillation (HD), steam distillation (SD), and microwave-assisted distillation (MV) to compare their chemical composition. The three essential oil samples were analyzed through GC/FID and GC/MS analyses. The samples were tested in vitro using different antioxidant techniques (DPPH, ABTS, CUPRAC, FRAP, PBD, and MCA), neuroprotective enzyme inhibitory activities (acetylcholine and butyl choline enzymes), and antidiabetic activities (α-amylase and α-glucosidase). The results showed that thirty-five volatile ingredients were detected and quantified. Monoterpenes represented the most abundant class in the three essential oils followed by sesquiterpenes. C. aurantium essential oil carried potential antioxidant activity where SD exhibited the highest antioxidant activity, with values arranged in the following order: FRAP (200.43 mg TE/g), CUPRAC (138.69 mg TE/g), ABTS (129.49 mg TE/g), and DPPH (51.67 mg TE/g). SD essential oil also presented the most potent α-amylase (0.32) inhibition while the MV essential oil showed the highest α-glucosidase inhibition (2.73 mmol ACAE/g), followed by HD (2.53 mmol ACAE/g), and SD (2.46 mmol ACAE/g). The SD essential oil exhibited the highest BChE and AChE inhibitory activities (3.73 and 2.06 mg GALAE/g), respectively). Thus, bitter orange essential oil can act as a potential source of potent antioxidant, antidiabetic, and neuroprotective activities for future drug leads.

Iberis sempervirens: Antiproliferative Potential from Our Garden

Glucosinolates (GSLs) extracted from various parts of Iberis sempervirens L., including seeds, stems, leaves, and flowers, were qualitatively and quantitatively assessed. The analyses of GSLs were performed by their desulfo counterparts using the UHPLC-DAD-MS/MS technique and by their volatile breakdown products, isothiocyanates, using the GC-MS technique. The GSL profile comprised various types, including those derived from: methionine, represented by methylsulfinylalkyl GSL (glucoiberin), and methylsulfanylalkyl GSL (glucoibervirin and glucoerucin); phenylalanine (glucotropaeolin); and tryptophan (4-methoxyglucobrassicin). Among these, the highest level of glucoiberin was detected in the leaves, reaching 35.37 µmol/g of dry weight (DW), while the highest level of glucoibervirin was detected in the seeds, reaching 18.51 µmol/g DW. To obtain GSL breakdown products, a variety of isolation methods were employed, including hydrodistillation in a Clevenger-type apparatus (HD), CH2Cl2 after myrosinase hydrolysis for 24 h (EXT), microwave-assisted distillation (MAD), and microwave hydrodiffusion and gravity (MHG). Volatile isolates were tested for their antiproliferative activity using an MTT assay against the human lung cancer cell line A549 and the human bladder cancer cell line T24 during an incubation period of 72 h. HD and MAD showed the best activity against T24, with IC50 values of 0.61 µg/mL and 0.62 µg/mL, respectively, while EXT was the most effective against the A549 cell line, with an IC50 of 1.46 µg/mL.

Polyphenols, Flavonoids, Mineral Elements, and Biological Activities of Ginger and Cinnamon Essential Oil and Extracts as Regulated by Their Isolation Procedures

Our research compared the chemical make-up of wild Ginger and cinnamon, including their essential oils (EOs), total phenol, and total flavonoid, for their antioxidant and antibacterial effects in vitro. The mineral (nutritional and poisonous) components of the plant were also identified in this investigation. Hydro distillation (HD), steam distillation (SD), and microwave-assisted distillation (MAD) were used to extract the EOs, and gas chromatography with flame ionization detection (GC-FID) and mass spectrometry detection (GC-MS) were used to examine them. 2,2-diphenyl-1-picrylhydrazyl (DPPH) was used to evaluate the EOs' antioxidant properties. The essential oil was analyzed, and twenty-six components were found to make up 97.73% of the oil with a yield of 0.202%. The primary components were pulegone (74.81%), menthone (13.01%) and piperitone (3.82%). Neutron activation analysis (INAA) and inductively coupled plasma optical emission spectrometry (ICP-OES) were used to detect twenty-one elements, including macro- and micro-elements (Ba, Br, Ca, Cl, Co, Cr, Cs, Eu, Fe, K, Mg, Mn, Mo, Na, Rb, Sb, Sc, Sr, Th, U, and Zn), with the mineral element concentration being very close to the FAO recommendation.

Glucosinolates of Sisymbrium officinale and S. orientale

Glucosinolates (GSLs) from Sysimbrium officinale and S. orientale were analyzed qualitatively and quantitatively by their desulfo-counterparts using UHPLC-DAD-MS/MS. Eight GSLs were identified in S. officinale, including Val-derived (glucoputranjivin) and Trp-derived (4-hydroxyglucobrassicin, glucobrassicin, 4-methoxyglucobrassicin, and neoglucobrassicin) as the major ones followed by Leu-derived (Isobutyl GSL), Ile-derived (glucocochlearin) and Phe/Tyr-derived (glucosinalbin). Different S. orientale plant parts contained six GSLs, with Met-derived (progoitrin, epiprogoitrin, and gluconapin) and homoPhe-derived (gluconasturtiin) as the major ones, followed by glucosinalbin and neoglucobrassicin. GSL breakdown products obtained by hydrodistillation (HD) and microwave-assisted distillation from S. officinale, as well as isopropyl isothiocyanate, as the major volatile in both isolates, were tested for their cytotoxic activity using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Generally, all volatile isolates showed similar activity toward the three cancer cell lines. The best activity was shown by isopropyl isothiocyanate at a concentration of 100 µg/mL after 72 h of incubation, with 53.18% for MDA-MB-231, 56.61% for A549, and 60.02% for the T24 cell line.

Geographic location and seasonality affect the chemical composition of essential oils of Lippia alba accessions

The chemical composition of essential oils (EO) is determined by genetic factors; however, these factors strongly interact with the environment, leading to significant changes in their constitution. The aim of this study was to evaluate the effect of geographic location on the chemical composition of the EO of seven accessions of Lippia alba (LA-03, LA-13, LA-24, LA-32, LA-36, LA-57, and LA-59) harvested monthly. Trails were conducted simultaneously in São Cristóvão, State of Sergipe, and Uberlândia, State of Minas Gerais, Brazil, from August 2017 to July 2018. The EO obtained by microwave-assisted distillation were analyzed by GC/MS-FID. In cluster analysis, it was observed that for all months, two groups were formed in each location. In Uberlândia, Group 1, with greater abundance of geranial + neral + linalool, included LA-03, LA-24, LA-32, LA-36, and LA-59; and Group 2, with greater abundance of carvone, included LA-13 and LA-57. The same response was observed in São Cristóvão, except for accession LA-24 in August, October, January, February, June, and July, which migrated from Group 1 to Group 2, joining LA-13 and LA-57. There were significant differences in the concentrations of the principal compounds between the locations. Greater concentrations of neral, 1,8-cineole, and ρ-cymene were obtained in accessions LA-03 (38.40%), LA-57 (11.50%), and LA-32 (7.97%), respectively, harvested in Uberlândia. Greater concentrations of carvone (75.66%), linalool (68.19%), geranial (55.90%), limonene (12.18%), piperitone (9.68%), and caryophyllene oxide (6.69%) were obtained in accessions LA-57, LA-24, LA-59, LA-57, LA-13, and LA-59, respectively, harvested in São Cristóvão. There were significant differences in the concentrations of the main compounds, showing that the chemical profiles of the essential oils of L. alba accessions are affected in a quantitative and qualitative way, both between harvests of monthly leaf regrowth in the same geographic region, and in harvests performed in different regions. These data reinforce the need for standardization of essential oil production in native perennial plants, for greater stability of the compounds.

The Essential Oil Composition of Helichrysum italicum (Roth) G. Don: Influence of Steam, Hydro and Microwave-Assisted Distillation

Helichrysum italicum (Roth) G. Don (Asteraceae), also known as immortelle, usually grows in the Mediterranean area. The composition of the essential oil (EO) of immortelle is a mixture of various aromatic substances, mainly monoterpenes and sesquiterpenes. Distillation is the most widely used method for extraction of EO immortelle, although the yield is very low (<1%). In this work, we aim to investigate how the use of different distillation methods affects the yield and chemical composition of immortelle EO. For this purpose, we applied two conventional methods: steam distillation (SD) and hydrodistillation (HD), and a modern (environmentally friendly) technique—microwave-assisted distillation (MAD). Wild immortelles from four different locations in Croatia were collected and carefully prepared for extraction. Each sample was then analyzed by gas chromatography–mass spectrometry (GC-MS). GraphPad Prisma statistical software was used to study the statistics between different groups of connections and analyze the data on the number of connections. The results show that HD gives a significantly higher yield (0.31 ± 0.09%) compared to MAD (0.15 ± 0.03%) and SD (0.12 ± 0.04%). On the other hand, the highest number of chemical compounds was identified with MAD (95.75 ± 15.31%), and most of them are subordinate compounds with complex structures. SD isolated EOs are rich in derived acyclic compounds with the highest percentage of ketones. The results show that the application of different distillation methods significantly affects the composition of the obtained immortelle EO, considering the yield of EO, the number of isolated, derived and non-derived compounds, chemotypes and compounds with simple (acyclic) and complex structures.

Separation of essential oil from fresh leaves of Phellodendron amurense rupr. By solvent-free microwave-assisted distillation with the addition of lithium salts

The essential oil was separated from the fresh leaves of Phellodendron amurense Rupr. by solvent-free microwave-assisted distillation in a rotating state with n-hexane extraction and LiCl addition, which ingeniously designed lithium salt addition, rotation unit, and n-hexane extraction effectively improved the yield and separation rate of essential oils. The factors that may affect essential oils yield were screened and optimized by single factor optimization, response surface methodology, and kinetic model to obtain the optimal conditions for the separation of essential oils by this method, which were LiCl content of 8%FW, microwave irradiation power 600 W and microwave irradiation time 40 min. And the yield of essential oils is 2.39 ± 0.12 mg/g in the optimum conditions by this method, which is highly consistent with the predictions from the response surface method (2.39 mg/g) and the first-order kinetic model (2.42 ± 0.04 mg/g). This method effectively ensures the uniform heating of the plant material and the rapid overflow of the essential oil by employing the rotating unit and the addition of LiCl, which effectively avoids the loss of the heat-sensitive components in the essential oil. Moreover, the solvent-free distillation of this method highly improves the heating rate, and the added LiCl can also be effectively recovered and reused, which effectively reduces the economic cost, and environmental stress and will result in a cleaner product. And an accurate quantitative analysis method of essential oils was established by n-hexane extraction-ultraviolet spectroscopy, which not only effectively avoided the loss of water-soluble components but also provided a new strategy for quantitative analysis of essential oils. In addition, the results of the kinetic model indicated that the separation rate constant of essential oils in this method was 1.34 times that of microwave-assisted hydrodistillation and 5.05 times that of conventional hydrodistillation. Therefore, this method is an efficient, green, and clean essential oil preparation method, which is very promising to replace existing methods in the future.

The Preparation of the Essential Oil from Pomelo (Citrus maxima ‘Shatian Yu’) Peel Using Microwave-Assisted Distillation by Pectinase Soaking and Its Anti-Fungal Activity

To verify the anti-fungus properties of the crop-harmful pseudocercospora, the essential oil (EO) of pomelo peel (PP) was extracted by a single factor combined with response surface optimization. Meanwhile, the composition and activity of EO were studied. The PP was squeezed by a screw extruder and pretreatmented by pectinase, then extracted by microwave-assisted steam distillation. The optimal conditions were as follows: pectinase dosage was 69.17 μmol/g, microwave power was 651.42 W and extraction time was 43.84 min. The dry weight (DW) yield of PPEO reached 14.63 mL/kg DW after BBD optimization. There were 23 compounds in the PPEO identified by GC-MS. Limonene, α-phrenbutene, and laurene in PPEO accounted for 79.31%, 4.72%, and 3.46%, respectively. In addition, the antifungal was effective when the concentration of PPEO was 3.5 mg/mL. Therefore, this study has guiding significance for the development of natural resources.

Pomelo (<i>Citrus grandis</i> L.) Essential Oil Extraction: A Comparison between Hydrodistillation and Microwave Assisted Hydrodistillation

Hydrodistillation (HD) is a traditional technique used in most extraction processes. On the other hand, microwave-assisted hydrogen distillation (MAHD), an advanced method using microwaves in the extraction process, has recently emerged. The chemical ingredients of essential oils obtained from pomelo (Citrus grandis L.) peels obtained by MAHD and by hydrodistillation (HD) were analyzed and compared gas chromatography-mass spectrometry (GC/MS). The results show that there is no significant difference between the two methods in terms of extraction efficiency, at around 4.45 to 4.7%. The main components of essential oils were Limonene, α-pinene, β-Myrcene and Sabinene. The content of those compounds showed no clear quantitative and qualitative difference between HD and MAHD. Experimental results show that the MAHD method provides a good alternative to extracting essential oils from grapefruit, saving time, operating costs and achieving more optimal levels. Keywords: Comparison, Pomelo (Citrus grandis L.), Essential oil, Hydrodistillation, Microwave assist hydrodistillation,

Chemical Composition and Biological Activity of Essential Oil and Extract from the Seeds of Tropaeolum majus L. var. altum.

Plant Tropaeolum majus L. (garden nasturtium) belongs to the family Tropaeolaceae and contains benzyl glucosinolate. The breakdown product of benzyl glucosinolate, benzyl isothiocyanate (BITC), exhibits various biological activities such as antiproliferative, antibacterial and antiinflammatory. In order to optimize the content of biologically active volatile compounds in plant extract and essential oil, the use of appropriate extraction technique has a crucial role. The current study investigates the effect of two modern extraction methods, microwave-assisted distillation (MAD) and microwave hydrodiffusion and gravity (MHG), on the chemical composition of volatile components present in the essential oil and extract of garden nasturtium (T. majus L. var. altum) seeds. Investigation of the biological activity of samples (essential oil, extract and pure compounds) was focused on the antiproliferative effect against different cancer cell lines: cervical cancer cell line (HeLa), human colon cancer cell line (HCT116) and human osteosarcoma cell line (U2OS), and the antibacterial activity which was evaluated against the growth and adhesion of Staphylococcus aureus and Escherichia coli to polystyrene surface. Essential oil and extract of garden nasturtium (T. majus) seeds were isolated by two extraction techniques: MAD and MHG. BITC and benzyl cyanide (BCN) present in the extract were identified by gas chromatography-mass spectrometry. Essential oil of T. majus showed higher antiproliferative activity (IC50<5 µg/mL) than T. majus extract (IC50<27 µg/mL) against three cancer cell lines: HeLa, HCT116 and U2OS. BITC showed much higher inhibitory effect on all tested cells than BCN. The essential oil and extract of T. majus showed strong antimicrobial activity against S. aureus and E. coli. This work represents the first comparative report on the antiproliferative activity of the essential oil and extract of T. majus seeds, BITC and BCN against HeLa, HCT116 and U2OS cells as well as their antimicrobial activity against S. aureus and E. coli. This study demonstrates that the essential oil of T. majus seeds exhibits stronger antiproliferative and antimicrobial activity than the plant extract.

Effect of Extraction Methods on Polyphenols, Flavonoids, Mineral Elements, and Biological Activities of Essential Oil and Extracts of Mentha pulegium L.

Our study evaluated the in vitro antioxidant properties, antibacterial and antifungal activities, anti-inflammatory properties, and chemical composition of the essential oils (EOs), total phenol, and total flavonoid of wild Mentha pulegium L. This study also determined the mineral (nutritional and toxic) elements in the plant. The EOs were extracted using three techniques—hydro distillation (HD), steam distillation (SD), and microwave-assisted distillation (MAD)—and were analyzed using chromatography coupled with flame ionization (GC-FID) and gas chromatography attached with mass spectrometry detector (GC-MS). The antioxidant effects of the EOs were tested with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ABTS (2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), while the antibacterial and antifungal activities of the EO and methanolic extract were tested using Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. Twenty-six compounds were identified in the essential oil, representing 97.73% of the total oil, with 0.202% yield. The major components were pulegone (74.81%), menthone (13.01%) and piperitone (3.82%). Twenty-one elements, including macro- and micro-elements (Ba, Br, Ca, Cl, Co, Cr, Cs, Eu, Fe, K, Mg, Mn, Mo, Na, Rb, Sb, Sc, Sr, Th, U and Zn), were detected using neutron activation analysis (INAA) and inductively coupled plasma optical emission spectrometry (ICP-OES), with the concentration of mineral element close to the FAO recommendation. The results show that the EOs and extracts from Mentha pulegium L. had significant antimicrobial activities against the microorganisms, including five human pathogenic bacteria, one yeast (Candida albicans), and one phytopathogenic fungi. The in vivo anti-inflammatory activities of the leaf extracts were confirmed. The results indicate that the EOs and extracts from Mentha pulegium L. have promising applications in the pharmaceutical industries, clinical applications, and in medical research.

Comparison of gastrointestinal stability of isothiocyanates from Tropaeolum Majus L. Altum using in vitro and ex vivo digestion methods

Tropaeolum majus L. is an annual herbaceous plant and a member of the Tropaeolaceae family, which belongs to the Brassicales order. It is an excellent source of flavonoids, carotenoids, phenolic acids, vitamin C, and it is a plant that contains the glucosinolate glucotropaeolin. The major degradation product of glucotropaeolin is benzyl isothiocyanate which is known for its various biological activities. In this study, an essential oil was isolated from the seeds of the Tropaeolum majus L. altum plant by microwave-assisted distillation and analysed using the GC-MS technique. Two compounds were identified, benzyl isothiocyanate as the major one (97.81%), and 2-phenylacetonitrile as a minor one (0.80%). Tropaeolum majus L. altum essential oil and pure benzyl isothiocyanate were then submitted to the two-phase in vitro and ex vivo digestion simulations. The analysis performed by the GC-MS/MS technique showed greater stability of benzyl isothiocyanate from essential oil after in vitro (97.57%), and ex vivo (73.47%) gastric phases of the simulated digestion methods, compared to its stability after in vitro (71.17%) and ex vivo (54.90%) intestinal phases. A similar trend was shown for pure benzyl isothiocyanate.

Hydro-distillation and microwave-assisted distillation of Sideritis raeseri: Comparison of the composition of the essential oil, hydrolat and residual water extract

Sideritis raeseri is widely used as a tea in the traditional medicine of many Mediterranean, Balkan, and Middle East countries. In this study, microwave-assisted hydro-distillation (MAHD) at different power levels (180 W, 360 W, and 600 W) of Sideritis raeseri essential oil was compared in terms of extraction time, yield, qualitative analysis, and operational cost with the conventional method of hydro-distillation (HD). Obtained essential oil, as well as hydrolats and residual water extracts, were chemically characterized. An extraction time of 16–32 min with MAHD at different powers provided yields of 0.61–0.67%, while HD gave 0.01% after 141 min. The main constituents in all essential oils were oxygenated sesquiterpenes, and their content was higher in MAHD (32.93–51.42%) than in oil from HD (17.62%). HD oil was characterized by higher concentration of oxygenated monoterpenes (14.95%) in relation to MAHD oil (8.87–14.16%). The essential oil obtained by MAHD at 600 W has a higher content of diterpenes (13.26%) than HD oil (8.59%). All hydrolats displayed the highest content of oxygenated monoterpenes. The highest contents of 8-hydroxyflavone 7-allosylglucosides compounds in residual water extracts were obtained by applying higher (600 W) microwave power. MAHD could be selected as a more appropriate extraction technique for S. reaseri essential oil than HD with respect to the extraction time, quality, and energy savings above 99%.

Optimization of the Essential Oil Extraction Process from Dong Van Marjoram (E. winitiana var. dongvanensis Phuong.) by Using Microwave Assisted Hydrodistillation, and the Bioactivities of the Oil Against Some Cancer Cell Lines and Bacteria

This study reports on the optimization of a microwave-assisted distillation process to obtain Dong Van marjoram essential oil, and the determination of its composition, content of constituents, and cytotoxic and antimicrobial activities. Using the response surface method (RSM), the optimal essential oil distillation conditions were determined as material size 0.74 (cm), water to material ratio 4.14:1 (mL/g), microwave power 302.4 (W), and distillation time 2.1 hours. At optimal conditions, the mass of Dong Van marjoram essential oil obtained was 0.887 ± 0.007 g, corresponding to a content of 0.6% essential oil in the material. GC-MS and GC-FID methods showed that the main chemical constituents of Dong Van marjoram essential oils obtained were rosefuran epoxide (44.9%), caryophyllene (10.8%), germacrene D (2.6%), and α-humulene (1.3%). The essential oil exhibited moderate inhibition against both tested cancer cell lines, with IC50 values of 23.9 µg/mL (for PC3) and 56.2 µg/mL (for A549). However, the oil exhibited strong effectiveness against three bacterial strains, Escherichia coli, Bacillus subtilis, and Staphylococcus aureus, and a yeast strain, Saccharomyces cerevisiae, with minimal inhibitory concentration (MIC) values ranged from 50 to 100 µg/mL.

Volatile composition of Perilla frutescens (L.) essential oil in Thai Binh Province, Vietnam extracted by microwave-assisted distillation method

The chemical composition of essential oils (EOs) obtained from Perilla frutescens (L.) (Lamiaceae) was determined. EOs of perilla was obtained by microwave-assisted extraction, giving the optimum content of 0.0941%. The composition of volatile constituents in the extracted oil was analyzed by mass chromatography (GC - MS), showing that the content of volatiles accounted for 97.58% of the total EOs content. Some major components in the obtained EOs were Perilla aldehyde 62.13%, Limonene (4.99%), Linalool (1.41%), Caryophyllene <E-> (6.72%), Humulene <a-> (1.11%), Caryophyllene oxide (2.45%), and Perilla alcohol (0.8%). Obtained perilla EOs may find the use as an alternative natural supplements in food, pharmaceutical and cosmetic products.

Determination of Volatile Components Extracted via Hydro and Microwave-Assisted Distillation of Thamnobryum alopecurum (Hedw.) Gangulee Grown in Turkey and Comparison of Their Antimicrobial Activities

The present study aimed to evaluate the chemical analysis and antimicrobial effects of the Thamnobryum alopecurum (Hedw.) Gangulee essential oils were obtained by different distillation methods (Clevenger apparatus hydrodistillation (HD) and microwave-assisted hydrodistillation (MD)). In this study obtained volatile oils were analyzed by gas chromatography-mass spectrometry which revealed the presence of forty-five compounds present in the essential oil obtained by HD method representing 99.48 % of the total identified compounds and thirty-four compounds were identified in the essential oil extracted by MD method representing 95.39 % of the total identified compounds. 3-octanone was the major constituent of the essential oils extracted by both HD (14.28 %) and MD (20.07 %). Terpenes were the major constituents in the essential oil extra-cted by both methods (54.41 % in HD and 52.21 % in MD) followed by oxygenated terpenoids (17.16 % in HD and 14.94 % in MD). The other major compounds of the essential oil in HD was limonene (9.65 %) followed by β-pinene (9.13 %), cuparene (6.04 %), gymnomitrone (5.72 %) and 4-epi-abietal (5.59 %). While in MD essential oil the other major compounds were β-pinene (12.20 %) followed by limonene (8.56 %), α-pinene (9.01 %), cupa-rene (6.44 %), abietadiene (5.97 %). The antimicrobial effects of the essential oils were determined tested quantitatively in respective broth media by using double microdilution and the minimal inhibition concentration (MIC) values (μg/mL). The isolated essential oils of T. alopecurum showed effective antimicrobial activities against Escherichia coli, Yersinia pseudotuberculosis, Staphylococcus aureus, Enterococcus faecalis, Bacillus cereus, Mycobacterium smegmatis and Candida albicans. However, no activity was not observed against Pseudomonas aeruginosa. The hydrodistillation method was found to be more effective than the microwave method in iden-tifying the chemical composition of the structure of T. alopecurum essential oil. While for antimicrobial study MD method was found to be more effective in terms of antimicrobial effect. The T. alopecurum thus is a potential source of an antimicrobial agent with a wide range of chemical compounds that could be responsible for their activity.

Correction to: Characterization of essential oil from Matricaria sevanensis by microwave-assisted distillation

In the original publication of the article, peak numbers were not given in figure 4. The corrected figure 4 is given below.

Innovative methods for the preparation of medical Cannabis oils with a high content of both cannabinoids and terpenes

Cannabis-based medications are being increasingly used for the treatment of different clinical conditions. Among all galenic formulations, olive oil extracts from medical Cannabis are the most prescribed ones for their easy preparation and usage. A great variety of methods have been described so far for the extraction of medical Cannabis oils to reach a high yield of Δ9-tetrahydrocannabinol (Δ9-THC), but poor attention has been paid to the preservation of the terpene fraction from the plant, which may contribute to the overall bioactivity of the extracts.In this context, the present study was aimed at the chemical characterization of different medical Cannabis oils prepared by following both innovative and existing extraction protocols, with particular attention to cannabinoids and terpenes, in order to set up a suitable method to obtain an extract rich in these chemical classes. In particular, six different extraction procedures were followed, based on different techniques, of which all but one included a decarboxylation of the plant material. The profile of cannabinoids was studied in detail by means of HPLC-ESI-MS/MS, while terpenes were characterized by means both GC-MS and GC-FID techniques coupled with solid-phase microextraction operated in the head-space mode (HS-SPME).An innovative method that is based on the extraction of the oil by dynamic maceration at room temperature from plant inflorescences, which were partially decarboxylated in a closed system at a moderate temperature and partially pre-extracted with ethanol, produced similar yields of bioactive compounds as that obtained by using a microwave-assisted distillation of the essential oil from the plant material, in combination with a maceration extraction of the oil from the residue. Both these new methods provided a higher efficiency over already existing extraction procedures of medical Cannabis oils and they can be applied to obtain a product with a high therapeutic value.

Effects on essential oil content of fennel (Foeniculum vulgare Mill.) and anise (Pimpinella anisum L.) fruits of microwave-assisted distillation and extraction methods

Bu araştırma, mikrodalga destekli distilasyon uygulamalarının rezene (Foeniculum vulgare Mill.) ve anason (Pimpinella anisum L.) meyvelerinde uçucu yağ ve sabit yağ oranları ile bileşenleri üzerine etkisini araştırmak amacıyla yürütülmüştür. Deneme tesadüf parselleri deneme desenine göre dört tekerrürlü olarak kurulmuştur. Meyvelere 0 (kontrol), 400, 600 ve 800 W güçte mikrodalga uygulandıktan sonra su distilasyonu yoluyla çıkarılan uçucu yağ oranı rezenede %0.96’dan (kontrol) %1.31’e (800 W), anasonda %1.98’den (kontrol) %2.10 (800 W)’a artış gösterdiği, anetol oranı ise sırasıyla %82.67’den (kontrol) %84.06’ya (400 W) ve %95.75’den (kontrol) %96.53’e (800 W) artış gösterdiği belirlenmiştir. Mikrodalga uygulanmış meyvelerde damıtma artığı olarak elde edilen posalarda sabit yağ oranı rezenede istatistiksel olarak önemli değişiklik göstermezken (%27.27-27.87), anasonda %29.87’den (kontrol) %30.30’a (800 W) artış göstermiştir. Rezenede sabit yağın en önemli yağ asidi bileşeni olan petroselinik asit oranı ise %74.86’dan (kontrol) %78.85’e artış göstermiş, anasonda ise petroselinik asit oranı birbirine yakın olmuştur. Çalışma sonucuna göre, ön işlem olarak milkrodalga uygulamalarının rezene ve anason meyvelerinin uçucu ve sabit yağ verimliliğinde ve kalitesinde olumlu etkisi olduğu tespit edilmiştir.