Conventional Hydrodistillation Research Articles

A comparative study of microwave-assisted and conventional hydro distillation methods for extracting essential oils and evaluating their antimicrobial activity from Cleome khorassanica: novel research

This study reports on the phytochemical analysis and antimicrobial activity evaluation of essential oils extracted from the aerial parts of Cleome khorassanica using both microwave-assisted water distillation (MAHD) and classical hydro distillation (HD). Gas chromatography coupled with mass spectrometry was used to analyze the chemical composition of the essential oils. The main components identified in the MAHD-extracted oil were γ-Cadinene (34.29%) and δ-Cadinene (19.52%), while o-Isopropenyltoluene (46.7%) and Duodecyclic acid (10.96%) were the major components in the HD-extracted oil. The MAHD technique showed higher extraction efficiency in a shorter time than the conventional HD method. The antimicrobial activity of the essential oils was evaluated using the minimum inhibitory concentration (MIC) method. The results showed that the essential oil and methanolic extract of Cleome khorassanica exhibited significant inhibitory activity against Staphylococcus aureus, Aspergillus niger, Aspergillus alternata and Fusarium solani. Gram-positive bacteria and fungi were more susceptible to the essential oil than Gram-negative bacteria. Furthermore, the samples extracted by MAHD demonstrated better antimicrobial activity compared to the HD-extracted oil.

Novel Electromagnetic Heat Hydrodistillation for Extraction of Essential Oil from Tangerine Peel.

A novel electromagnetic heat method is presented for green extraction of natural compounds from peel residue. In the processing cavity obtained through 3D printing, a core made of amorphous alloy was applied to strengthen the magnetic flux. During the process, an induced electric field was produced in the extract medium owing to an oscillating magnetic field at 50 kHz rather than a pair of electrodes; thus, electrochemical reactions could be avoided. A thermal effect and temperature rise were observed under the field, and essential oil was obtained via this electromagnetic heat hydrodistillation. In addition, the numerical relationships between magnetic field, induced electric field (IEF), induced current density, and temperature profile were elaborated; they were positively correlated with the extraction yield of essential oils. It was found that the waveforms of the magnetic field, induced electric field, and excitation voltage were not consistent. Using a higher magnetic field resulted in high current densities and terminal temperatures in the extracts, as well as higher essential oil yields. When the magnetic field strength was 1.39 T and the extraction time was 60 min, the maximum yield of essential oil reached 1.88%. Meanwhile, conventional hydrodistillation and ohmic heating hydrodistillation were conducted for the comparison; all treatments had no significant impact on the densities. In addition, the essential oil extracted by electromagnetic heat had the lowest acid value and highest saponification value. The proportion of monoterpenoids and oxygen-containing compounds of essential oil extracted by this proposed method was higher than the other two methods. In the end, the development of this electromagnetic heat originating from magnetic energy has the potential to recover high-value compounds from biomass waste.

Chemical constituents and in vitro biological activities of Mentha rotundifolia’s essential oils extracted by ultrasound-assisted hydrodistillation compared to conventional hydrodistillation

Chemical constituents and in vitro biological activities of Mentha rotundifolia’s essential oils extracted by ultrasound-assisted hydrodistillation compared to conventional hydrodistillation

Co-detection of eugenol and butylated hydroxyltoluene by green and selective hydrodistillation of Heliotropium europaeum L. using ionic liquids as additives

This study is the beginning of the research that focuses on uncon-ventional ionic liquids (ILs) hydrodistillation (HD) extraction of the essential oil of Heliotropium europaeum L. using ILs as additives. Two ILs based on 1- butyl-3-methylimidazolium were used by switching the anions (Cl- and PF6-). The effect of mass percent of the added ILs on its yield and composition was evaluated. Compared to the conventional HD, ILs-HD gives a higher yield of essential oils (0.10?0.36 %). Particularly, with [C4mim][PF6], the observation of morphological changes using scanning electron microscopy (SEM) con-firmed the effectiveness of the ionic liquid in this distillation process. The GC? ?MS analysis of essential oils (EOs) revealed the presence of sixty-six com-pounds in HD, ILs-HD methods. Gas chromatography?mass spectrometry ana-lysis of the EOs revealed the predominance of eugenol (1.70?72.35 %), but-ylated hydroxytoluene (8.95?65.39 %) and phytol (18.20 %). The new distil-lation methods of H. europaeum with ILs identifies more compounds (50 com-pounds in ILs-HD [C4mim][PF6]; 22 compounds in ILs-HD ([C4mim][Cl]) than conventional hydrodistillation (25 compounds in HD). Therefore, the ILs- -based hydrodistillation approach is superior in improving the production of EOs. It is important to emphasize that the data presented in this study are not yet available for any of this Algerian Heliotropium species of genus and present the great potential of this medicinal plant as a source of novel bioactive extracts with possible therapeutic uses.

Boosting the essential oil yield of Coriandrum sativum L. using choline chloride-based NADES: an optimized and systematic study employing response surface methodology (RSM)

Coriander essential oil (CEO) is one of the most versatile and powerful essential oils used in the food and pharmaceutical industries, thanks to its numerous properties. Different choline chloride-based natural deep eutectic solvents (NADES) were studied as additives in the hydrodistillation preparation of CEO, and most were able to increase oil yield compared to conventional hydrodistillation. Among these different NADES, the use of choline chloride (ChCl)-urea (N11) led to a yield increase of up to 31.5% in comparison to traditional water hydrodistillation. Few differences were observed in the composition of the oils, except in those prepared using acidic ChCl-citric acid NADES, which led to a significant variation in the CEO composition. The phytochemical profile of CEOs was investigated, and the enantiomeric fractions (EFs) of the most important monoterpene alcohol, linalool, were determined. No differences in the EFs were observed for all the CEOs (86.77% (S)-(+) enantiomer), except for those obtained by using choline ChCl-citric acid (59.26% (S)-(+) enantiomer). Subsequently, a three-level custom design (CD) was used to study the influence of four independent variables: plant-to-N11 ratio, pre-treatment temperature, pre-treatment time, and water percentage. The response surface methodology (RSM) was used to evaluate and optimize the effects of the chosen factors. The RSM results show that the plant-to-N11 ratio, pre-treatment temperature, and water percentage were highly significant in influencing the extraction yield, while the pre-treatment time was not a significant influence. The highest extraction efficiency was obtained using N11 in a 1:4 (w/w) plant-to-NADES ratio, 40 °C and 30 min US-assisted pre-treatment, and 30% (w/w) water content, resulting in an additional 26.6% increase compared with the screening phase. Overall, using the optimized conditions, we were able to enhance the extraction yield up to a total of a 63% (0.77 ± 0.04% (CEOref) vs. 1.10 ± 0.09% (CEOopt)).

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.

Essential oil extraction from lavender using negative pressure cavitation extraction and coating to extend grape shelf life

The purpose of this investigation was to extract the essential oil from lavender using the negative pressure cavitation extraction (NPCE) method and compare it to conventional hydro-distillation, as well as to assess the effect of extraction techniques on the yield and physicochemical activity of lavender essential oil. Linalyl acetate, camphor, 1,8-cineole (eucalyptol), borneol, terpinen-4-ol, caryophyllene, geraniol, geranyl acetate, and bisabolol are some of the primary compounds extracted from lavender essential oil. The total phenolic content and antioxidant activity of essential oil were measured. The lavender essential oil extracted using the NPCE technique had a total phenolic content of 73.17 ± 0.97mg gallic acid equivalents (GAE)/100ml. Half-maximal inhibitory concentration (IC50) refers to the ability of lavender essential oil extract to scavenge 50% of the original DPPH radicals. The lavender essential oil extracted using the NPCE process has an IC50 of 285.70 ± 0.46g/mL. The impact of sodium alginate edible coating in conjunction with lavender volatile oil (0.5, 1, 1.5, and 2% w/v) on overall grape quality was studied over 9 days period at 4°C. It was revealed that the sodium alginate coating infused with lavender essential oil preserved grape quality. The most effective application, however, was sodium alginate combined with lavender essential oil of 1%. Furthermore, the inclusion of lavender volatile oil in the sodium alginate coating decreased the microbial load.

Juniper berry essential oils as natural resources of biological and pharmacological high-valuable molecules

Dried juniper berries (Juniperus communis L.) as a source of nutritionally valuable essential oil (EOs) were used for their isolation by conventional hydrodistillation (HD) and modern technique - microwave-assisted hydrodistillation (MWHD). The chemical composition, and biological and microbiological potential of the isolated EOs, prepared by using different microwave energy power and microwave treatment time, were investigated. The essential oil kinetic release curves were mathematically modeled. Results of the research indicate that MWHD was a more favorable technique for EO isolation with higher biological activity than HD, where lower power of microwave radiation was more suitable for realizing a higher antioxidant activity. However, there were no statistically significant differences in the composition of essential oils obtained by different distillation techniques. Reduction of the isolation time of MWHD contributes to obtaining EOs with a very pronounced ability to inhibit excessive enzyme activity, while the production of EOs with strong microbiological activity requires a long isolation time. The EO of juniper berries obtained by MWHD could be characterized as a powerful natural product for the creation and formulation of new, as well as improving the quality of already existing food, pharmaceutical, and cosmetic products.

Natural deep eutectic solvents (NADESs) assisted extraction of essential oil from Nardostachys jatamansi (D.Don) DC with insecticidal activities

Different Natural deep eutectic solvents (NADESs) combinations were employed as a cosolvent in the conventional hydro-distillation method for extracting essential oil (EO) from the roots of Nardostachys jatamansi (D.Don) DC. Subsequent enhancement in EO yield along with phytochemical variation was observed on implementing NADESs as an extraction media compared to conventional hydro-distillation method using water. Among different combinations, the highest yield (1.7% v/w) of EO was observed with NADES-5 (choline chloride: maleic acid; 2:1) as compared to the conventional method (0.9% v/w, lowest yield among all combinations). Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis of all extracted EOs led to the identification of 34 compounds accounting for 76.13–87.87% of the total area percentage. Principal component analysis (PCA) and clustered heatmaps were used for multivariate analysis showing discrimination of the constituents in different EOs. Valeranone (31.22–12.60%) and nerolidol (21.39–1.82%) were observed in all samples, whereas some molecules like bisabolol, α-cadinol, and nootkatone were specific to certain samples, showing variability in chemical composition. EOs were further examined for their insecticidal and enzyme inhibitory activity against Aphis craccivora Koch (Hemiptera: Aphididae) and Planococcus lilacinus Cockerell (Hemiptera: Pseudococcidae), which are major sucking pests of legumes, vegetables, fruit and plantation crops. Results showed that the EOs obtained with water, NADES-4 (choline chloride: lactic acid; 1:2), 1 (choline chloride: oxalic acid; 1:1), 3 (choline chloride: lactic acid; 1:1), and 6 (glycerol: lactic acid; 1:1) showed promising toxicity (LD50 =0.80–0.98 µL/insect) against A. craccivora. Similarly, EOs obtained with water, NADES-3 (choline chloride: lactic acid; 1:1), and 4 (choline chloride: lactic acid; 1:2) also showed toxicity (LD50 =0.90–1.19 µL/insect) against P. lilacinus, which may be attributed to the presence of high concentration of metabolites such as valeranone, β-patchoulene, nerolidol, α-cadinol and viridiflorol. Further, LD50 concentrations of EO from water showed significant inhibition of glutathione S-transferase (8.52 ± 3.91 and 11.83 ± 5.68 nmol/min/mL) and acetylcholinesterase (0.67 ± 0.04 and 0.75 ± 0.09 mU/mg) after 24 h in A. craccivora and P. lilacinus, respectively.

Antioxidant and Antimicrobial Properties and GC-MS Chemical Compositions of Makwaen Pepper (Zanthoxylum myriacanthum) Extracted Using Supercritical Carbon Dioxide.

This research aimed to optimize pressure (10-20 MPa) and temperature (45-60 °C) conditions for supercritical fluid extraction (SFE) of Makwaen pepper (Zanthoxylum myriacanthum) extract (ME) in comparison to conventional hydro-distillation extraction. Various quality parameters, including yield, total phenolic compounds, antioxidants, and antimicrobial activities of the extracts, were assessed and optimized using a central composite design. The optimal SFE conditions were found to be 20 MPa at 60 °C, which resulted in the highest yield (19%) and a total phenolic compound content of 31.54 mg GAE/mL extract. IC50 values for DPPH and ABTS assays were determined to be 26.06 and 19.90 μg/mL extract, respectively. Overall, the ME obtained through SFE exhibited significantly better physicochemical and antioxidant properties compared to ME obtained through hydro-distillation extraction. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that beta-pinene was the major component in the ME obtained through SFE (23.10%), followed by d-limonene, alpha-pinene, and terpinen-4-ol at concentrations of 16.08, 7.47, and 6.34%, respectively. On the other hand, the hydro-distillation-extracted ME showed stronger antimicrobial properties than the SFE-extracted ME. These findings suggest that both SFE and hydro-distillation have the potential for extracting Makwaen pepper, depending on the intended purpose of use.

Volatile Compounds and Biological Activity of the Essential Oil of Aloysia citrodora Paláu: Comparison of Hydrodistillation and Microwave-Assisted Hydrodistillation.

Aromatic plants are a remarkable source of natural products. Aloysia citrodora Paláu (Verbenaceae), commonly known as lemon verbena, is a relevant source of essential oils with potential applications due to its lemony scent and bioactive properties. Studies carried out on this species have focused on the volatile composition of the essential oil obtained by Clevenger hydrodistillation (CHD), with little information available on alternative extraction methodologies or the biological properties of the oil. Therefore, this work aimed to compare the volatile composition, antioxidant activity, cytotoxicity, anti-inflammatory and antibacterial activities of the essential oil extracted by conventional hydrodistillation by Clevenger (CHD) and Microwave-Assisted Hydrodistillation (MAHD). Significant differences (p < 0.05) were observed for some compounds, including the two major ones, geranial (18.7-21.1%) and neral (15.3-16.2%). Better antioxidant activity was exhibited by the MAHD essential oil in DPPH radical scavenging and reducing power assays, while no differences were observed in the cellular antioxidant assay. The MADH essential oil also presented higher inhibition against four tumoral cell lines and exhibited lower cytotoxicity in non-tumoral cells as compared with Clevenger-extracted essential oil. In contrast, the latter showed higher anti-inflammatory activity. Both essential oils were able to inhibit the growth of eleven out of the fifteen bacterial strains tested.

Variation in Yield, Chemical Composition and Biological Activities of Essential Oil of Three Curcuma Species: A Comparative Evaluation of Hydrodistillation and Solvent-Free Microwave Extraction Methods.

The essential oils of three medicinally important Curcuma species (Curcuma alismatifolia, Curcuma aromatica and Curcuma xanthorrhiza) were extracted using conventional hydro-distillation (HD) and solvent free microwave extraction (SFME) methods. The volatile compounds from the rhizome essential oils were subsequently analysed by GC-MS. The isolation of essential oils of each species was carried out following the six principles of green extraction and comparison was made between their chemical composition, antioxidant, anti-tyrosinase and anticancer activities. SFME was found to be more efficient than HD in terms of energy savings, extraction time, oil yield, water consumption and waste production. Though the major compounds of essential oils of both the species were qualitatively similar, there was a significant difference in terms of quantity. The essential oils extracted through HD and SFME methods were dominated by hydrocarbon and oxygenated compounds, respectively. The essential oils of all Curcuma species exhibited strong antioxidant activity, where SFME was significantly better than HD with lower IC50 values. The anti-tyrosinase and anticancer properties of SFME-extracted oils were relatively better than that of HD. Further, among the three Curcuma species, C. alismatifolia essential oil showed the highest rates of inhibition in DPPH and ABTS assay, significantly reduced the tyrosinase activity and exhibited significant selective cytotoxicity against MCF7 and PC3 cells. The current results suggested that the SFME method, being advanced, green and fast, could be a better alternative for production of essential oils with better antioxidant, anti-tyrosinase and anticancer activities for application in food, health and cosmetic industries.

A new and rapid process as an efficacy essential oils extraction system of Ammoides verticillata (Duby) Briq.

Ammoides verticillata (Duby) Briq. (A. verticillata) is an aromatic plant belonging to the family Apiaceae. The present study optimized a rapid procedure of essential oils (EOs) extraction from the species. Two extraction methods were compared: hydro-distillation (HD) and Pressure Cooker Pre-treatment Hydrodistilation (PCPHD). The results showed that the maximum essential oil yield was obtained from 50 g of the uncrushed plant material after 15 min of maceration under a heating temperature of 250°C for HD. The results revealed that the PCPHD produced quickly higher A. verticillata essential oils yield (4.22%) for 90 min compared with the HD (2.88%) for 180 min. The PCPHD provided a high amount of oxygenated compounds compared to the conventional HD method. The extraction cost, time, and energy were significantly lower in the PCPHD method compared with the HD method. Moreover, the energy necessary to extract A. verticillata EOs was 2.1 kWh for 180 min of HD and 1.05 kWh for 90 min of PCPHD. The amount of carbon dioxide released into the atmosphere during HD extraction (1.68 kg CO2/g EOs) was higher than that released during PCPHD extraction (0.84 kg CO2/g EOs). In addition, the wastewater from the PCPHD (0.177 L/g EOs) was far less than that from the HD (0.26 L/g EOs). The PCPHD was an efficient green alternative and economical method to extract a high yield of the A. verticillata essential oil.

Conventional vs. Microwave-Assisted Hydrodistillation: Influence on the Chemistry of Sea Fennel Essential Oil and Its By-Products.

The main objectives of this study were to investigate the effects of the applied essential oil (EO) isolation method, conventional hydro-distillation (HD), and microwave-assisted hydro-distillation (MHD) on the chemical profile of sea fennel (Crithmum maritimum L.) essential oil and to investigate the main constituents present in the liquid by-products of EOs isolation (hydrolate and residual wastewater). Headspace-solid phase microextraction (HS-SPME) was used to isolate hydrolate components, while gas chromatography coupled with mass spectrometry (GC-MS) was used to detect and analyse the chemical constituents of the essential oils and hydrolates. The phenolic composition of the wastewater extracts was analysed by high performance liquid chromatography (HPLC). The EO obtained by MHD had a higher yield of limonene and sabinene. The chemical composition of the hydrolates differed from the EO compositions. The content of terpinen-4-ol in the MHD hydrolate was higher, while several compounds were detected in relatively high proportions only in the HD hydrolate. MHD also resulted in a higher phenolic content of the wastewater, where an increase in the concentration of chlorogenic acid was also observed. It can be concluded that the isolation method had a great influence on the profile of sea fennel EOs, especially on their corresponding hydrolates and residual wastewater extracts. Due to their valuable chemical composition, these by-products can be a cost-effective source of bioactive compounds that have great potential for use in various industries.

Cleaner production of essential oils from Indian basil, lemongrass and coriander leaves using ultrasonic and ohmic heating pre-treatment systems

Indian basil (Ocimum basillicum), lemongrass (Cymbopogon flexuosus) and coriander (Coriandrum sativum) leaves are a good source of aromatic oils; however, their extraction volume is low. Hence, two pre-treatment systems (ohmic-heating and ultrasonic) were devised for extraction of essential oils (EO) from the leaves of these three plant spp., which consequently enhanced the EO yield and saved the time and energy. First of all, an experimental set-up was developed for ohmic-heating pre-treatment which was subjected to the optimization of electric conductivity of lemongrass and coriander leaves at 26.25 V/cm and for Indian basil at 22.5 V/cm voltage gradient. An Experimental setup was also developed for ohmic heating-assisted hydro-distillation (OHD). Finally, conventional Clevenger hydro-distillation (CHD), OHD, ultrasonic-assisted conventional hydro-distillation (UACHD) and ultrasonic-assisted ohmic-heating hydro-distillation (UAOHD) methods were evaluated for their effectiveness in the extraction of the EOs. The OHD took 3.5 h time with 410 W power consumption compared to 5 h time and 500 W power consumption in CHD of sleeted leaves. Likewise, a saving of ~ 86% in time and 74% in energy consumption was observed for EO extraction through UAOHD over CHD. Quantity of EOs extracted from all three aromatic plant spp. leaves followed the trend of UAOHD > UACHD > OHD > CHD methods, respectively. Overall, ultrasonic pre-treatment coupled with ohmic-heating assisted hydro-distillation (UAOHD) proved as an innovative and effective clean EO extraction technology which took shorter extraction time and lesser energy consumption with better EO yield over the UACHD, OHD and CHD methods from the leaves of Indian basil, lemongrass and coriander.

Essential oils of Psidium cattleianum Sabine leaves and flowers: Anti-inflammatory and cytotoxic activities.

Introduction: Psidium cattleianum Sabine is a Brazilian native shrub cultivated for its edible fruit araçá (strawberry guava). P. cattleianum is recognized for health and food applications, although the essential oils (EOs) from the Egyptian inhabitant are not fully explored. The current study investigated the anti-inflammatory and cytotoxic activities of EOs from P. cattleianum leaves and flowers. Materials and methods: The EOs were obtained by three different methods viz; the conventional hydro-distillation, microwave assisted hydro-distillation, and supercritical fluid extraction, while their analysis was accomplished using GC/MS. The derived EOs were screened for their anti-inflammatory activity in the 5-lipoxygenase, COX-1, and COX-2 enzyme based assays, while the anticancer potential was deduced from MTT cytotoxic assay, cell cycle, and western blotting analysis. Results and discussion: Among other methods, supercritical fluid extraction offered the highest EO yield, 0.62% (leaves) and 1.4% (flowers). GC/MS identified β-caryophyllene and α-humulene in both organs with high but variable percentages. The leaves demonstrated strong activity in inhibiting the 5-lipoxygenase enzyme (IC50 2.38), while the flowers, in inhibiting COX-2 (IC50 2.575). Moreover, the leaves showed potent, selective cytotoxicity to MCF-7 cells (IC50 5.32) via apoptosis by modulating the p53/Bax/Bcl2 axis. The deduced activities are possible due to the synergism between the volatile components that endorses P. cattleianum leaves' EOs in the management of breast cancer and inflammatory disorders.

Comparison of Conventional Extraction Techniques with Superheated Steam Distillation on Chemical Characterization and Biological Activities of Syzygium aromaticum L. Essential Oil

Syzygium aromaticum L. is an aromatic plant with a significant amount of essential oil (EO), which is used in food, medicine, for flavoring, and in the fragrance industry. The purpose of this study was to comparatively evaluate the chemical composition, yield, and antioxidant and antifungal activities of Syzygium aromaticum essential oils extracted by the conventional hydro-distillation, steam distillation, and the emerging superheated steam distillation methods. It was noticed that the extraction methods significantly influenced the yield, chemical composition, and antioxidant and antimicrobial activities of essential oils. The maximum yield was obtained using superheated steam distillation, followed by hydro-distillation and steam distillation. The antioxidant potential of EO extracts was evaluated following the scavenging of 2,2-dipenyl-1-picrylhydrazyl radicals, hydrogen peroxide scavenging activity and ferric reducing power assays. Results revealed that EO extracted superheated steam distillation exhibited the highest antioxidant activity. GC-MS analysis depicted eugenol (47.94–26.50%) and caryophyllene (20.24–9.25%) as the major compounds of Syzygium aromaticum EOs. The antimicrobial activity of EO extracts was evaluated, via the resazurin microtiter plate assay, microdilution broth assay, and disc diffusion methods, against normal and food pathogenic bacterial and fungal strains. After comparative evaluation, it was observed that superheated steam extracted EO exhibited the highest antimicrobial potential. Overall, methodical evaluation disclosed that superheated steam distillation is an effective method to extract EOs from plant sources, with greater yield and promising biological activities.

Enhancing Yields and Antioxidant Activities of Caraway Seeds Essential Oil by Ultrasonic Treatment Combined with Hydro-distillation, and Microwave-assisted Hydro-distillation

This study examined the effects of ultrasonic treatment on the amount and quality of essential oils extracted from caraway seeds using ultrasonic treatment followed by hydro-distillation and ultrasonic treatment followed by microwave-assisted hydro-distillation. Afterward, the obtained results were compared with those of untreated extracts issued from conventional hydro-distillation and microwave-assisted hydro-distillation. The essential oil yields ranged from 1.18 ± 0.09 to 1.36 ± 0.09% w/w, depending on the extraction technique. Analysis by gas chromatography coupled with mass spectrometry showed the presence of 21 compounds in all the extracts. Produced essential oils consisted of 9.65 ± 1.742 % to 18.59 ± 1.377 % monoterpenes hydrocarbons and 77.20 ± 2.847 to 84.60 ± 1.909 % oxygenated monoterpenes. The main components were limonene and carvone, but the amounts of each component depend on the methods. Additionally, the antioxidant activity of caraway seeds essential oils was determined using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. The antioxidant ability of the examined oils was moderate, and the USMAHD oil median inhibitory concentration (IC50) value was the lowest. Moreover, a statistical investigation paved the way for a possible correlation between the carvone/limonene ratio and IC50. Consequently, this aspect, which is the potential for improving the extract’s quality by modifying the ratio of the target components known for their high antioxidant effects, made this study novel.

Influence of enzymatic pretreatment on yield and chemical composition of Rosmarinus officinalis essential oil

Abstract Effect of enzymatic pretreatment before hydrodistillation process on yield and composition of Rosmarinus officinalis essential oil was studied. Results obtained by using two selected commercial enzymes applied in food and beverage industry were compared. Control process with non-enzymatic pretreatment in analogous conditions was also performed for proper interpretation of results. Application of gas chromatography with mass selective detector (GC-MS) enabled analysis and comparison of essential oils composition. Moreover, total phenolic content (TPC) was determined spectrophotometrically in post-processing hydrolates, which are also valuable products e.g. for cosmetic applications. Modifications of isolation process by pretreatment with selected enzymes resulted in significant increase in essential oil yields in comparison to conventional hydrodistillation and control process with non-enzymatic pretreatment in analogous conditions. No substantial changes in the composition of obtained essential oils were observed. In post-processing hydrolates higher values of total phenolic content (TPC) were found both after enzymatic and non-enzymatic pretreatment.