Essential Oil Yield Research Articles

Chemometrics of the Seasonal Influence on Chemical Composition, Yield, Antioxidant Capacity, and Anti-Candida Activity of Alpinia nutans Essential Oil Growing in the Brazilian Amazon Region.

Alpinia nutans (L.) Roscoe (Zingiberaceae) is used in folk medicine as an antiviral, anti-inflammatory, and antioxidant. This study aimed to evaluate the seasonality effects on the yield, chemical composition, antioxidant capacity, and anti-Candida activity of the A. nutans essential oil (EO). The specimen was collected monthly for 1 year in Belém, Pará, Brazil. The leaf EOs were obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC/MS), and the antioxidant capacity was evaluated by DPPH and β-carotene/linoleic acid. The EO yield showed no significant difference between dry (1.80%±0.29) and rainy (1.75%±0.11) seasons. The main chemical constituents identified in the EOs were terpinen-4-ol (13.93%-23.14%), 1,8-cineole (15.83%-18.43%), and p-cymene (14.41%-20.16%). Hierarchical cluster analysis (HCA) and principal component analysis (PCA) showed three groups with major constituents in different proportions. None of the samples showed significant inhibition in the DPPH and β-carotene/linoleic acid antioxidant method. Analyzing the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC), the samples from dry and rainy seasons showed high activity against strains of Candida albicans (MIC 5mg/mL; MFC 10mg/mL), Candida parapsilosis (MIC 2.5mg/mL; MFC 10mg/mL), and Candida tropicalis (MIC 10mg/mL; MFC 10mg/mL). There were only quantitative variations in the chemical composition of A. nutans EO. The anti-Candida potential of the EO was also not influenced by seasonality. The A. nutans EO may be promising to produce anti-Candida phytopharmaceuticals. However, the chemical variability of this species throughout the year should be considered for this purpose.

Yield and quality features of some rosemary (Rosmarinus officinalis L.) genotypes

Rosemary has broad distribution in the world, especially in the Mediterranean region and naturally grows on the west and south coasts of Turkey. In this study, a total of 70 genotypes, with 58 local samples collected from different locations in Turkey and 12 foreign samples obtained from different countries located around the Mediterranean belt, were placed under morphological observation in 2021-2022 by creating an observation garden in the trial fields of Yalova Atatürk Horticultural Central Research Institute. As a result of the research, according to general averages for 2021 and 2022, among morphological and agronomic features, the plant height was 41.1 - 82.3 cm, green herb yield 268.2 - 1137.7 kg/ha, dry herb yield 66.2-110.6 kg/ha, dry leaf yield 51.9 - 71.5 kg/ha, and essential oil yield 0.2 - 2.9 ml/ha. Among quality features, the essential oil proportion was 0.4 - 4.8%, and phenolic compounds included rosmarinic acid (RA) 2.1 - 12.3 mg/g, carnosic acid (CA) 9.3 - 60.7 mg/g and carnosol (CAR) 1.3 - 4.9 mg/g. In conclusion, 9 rosemary genotypes identified with high green herb yield, dry leaf yield, phenolic compounds, essential oil proportion and essential oil quality are B2, B3, B5, B6, B8, B52, B62, B69 and B70, and recommended to include these genotypes in repeated yield trials.

Hydrodistillation Optimization for Borago officinalis L. Essential Oil and Its Chemical Composition Analysis.

The essential oil extracted from Borago officinalis L. aerial parts using hydrodistillation contains several compounds, although it yields low amounts. For the first time, this study investigated the effects of hydrodistillation parameters and optimized conditions to maximize the yield of B. officinalis essential oil while characterizing its chemical composition using gas chromatography-mass spectrometry. A single-factor evaluation of three extraction parameters-extraction time, liquid-to-solid ratio, and soaking time-revealed optimal conditions of 4h, 10:1mL/g, and 2h, respectively. Subsequently, the Box-Behnken response surface method produced a significant polynomial model, determining optimal conditions of an extraction time of 5h, a liquid-to-solid ratio of 11.06:1mL/g, and a soaking time of 2h, 17min, and 34s, resulting in an essential oil yield of 0.42%. A total of 21 compounds were identified in B. officinalis essential oil, predominantly nonacosane (29.15%) and phytol (27.92%).

Assessment of AMMI model for delineating the stability indices of high yielding variety of Java Citronella (Jor Lab C-5) evaluated in different location of NE India

An industrially important plant, Cymbopogon winterianus Jowitt ex Bor commonly known as Java Citronella belonging to Poaceae family gains its significance due to the presence of aromatic constituents and its capacity to yield a high quantity of essential oil. However, due to varied agronomic and climatic conditions, fluctuations in the chemical constituents and essential oil yield can be noticed. However, till now studies on stability analysis of Citronella are very scarce. Focusing the crop’s exceptional oil-yielding capacity and its high importance in industrial purposes extensive commercial cultivation of superior variety of Citronella is need of the hour. Hence, a study was conducted to establish a stable genotype of Java citronella where Jor Lab C-5 was taken to test the stability along with two check genotypes (Jor lab C-2 and Assam local). For two years (2021-2022 and 2022-2023) six agronomical traits were constantly studied with two sets of environmental factors for the eight different locations in a randomized block design. The Analysis of variance (ANOVA) by regression method revealed herbage recovery rate and essential oil yield as extensively high for Jor Lab C-5 as compared to the other two genotypes. Further, AMMI (Additive Main-effects and Multiplicative Interactions) ANOVA was used for the confirmation of uniform performance of various characters where Jor Lab C-5 was found to be stable in case of plant height, herbage yield, essential oil yield, citronellal content, and total essential oil yield. The GC-MS analysis of essential oil revealed 19 compounds with area percent 94.28% of which citronellal (42.52%) outcomes as major constituent. Additionally, environment such as Runne, Khehoyi, Yaongyimsen, and Jorhat were considered as the best suited locations for Jor Lab C-5, thus highlighting its multi-location stability and its potential industrial significance in the long run.

Seasonal metabolic variation in the essential oil composition of various Tabebuia species and evaluation of their anti-inflammatory activity in vitro and in silico.

The seasonal variation in essential oil from four Tabebuia species, T. impetiginosa, T. rosea, T. argentea, and T. guayacan, was explored using gas chromatography-mass spectrometry analysis. A total of 90 components were tentatively identified. Among the four Tabebuia species, the most predominant components in spring were phytol (67.5%), limonene (50.1%), (Z,Z,Z)-7,10,13-hexadecatrienal (67.5%), and 1-octen-3-ol (80.4%), respectively. Chemometric discrimination of the four Tabebuia species was performed employing principal component analysis, which classified the samples into three main clusters while the rest of the samples were scattered in the whole plot. The season of collection impact on essential oils composition and yield was illustrated. 5-Lipooxygenase inhibitory effect of spring season essential oils was assessed, showing that all essential oils exhibited certain inhibition, where T. rosea showed the most potent effect, exhibiting an IC50 value of 1.8 μg/mL, compared to the standard zileuton (0.68 μg/mL). Moreover, an in silico molecular docking study was performed for the predominant metabolites against the 5-LOX active pocket. Among all the docked compounds, eicosane showed the best fitting score, then norphytane, with ∆G of -38.39 and -29.77 kcal/mol, respectively. Thus, Tabebuia species could offer a natural and relatively safe anti-inflammatory candidate that requires further clinical trials to be supported.

The property differences of essential oils extracted by two methods from Dolichos lablab flowers: chemical composition, anti-microorganism and cholinesterase inhibition activities

In this study, the essential oils of Dolichos lablab (syn. Lablab purpureus) flowers (EOFs) were extracted by enzymatic pretreatment plus microwave extraction (EP-ME) method, and the key factors affecting yield of essential oils were investigated. The kinetic curves of essential oils extracted by EP-ME method were fitted, and the results showed that the first-order kinetic model was more appropriate for essential oils extracted by EP-ME method. Under the optimal extraction conditions, EP-ME method not only had high extraction yield, but also had low consumption time. The yield of essential oil extracted by EP-ME method (0.41 ± 0.021% g/g) was 51.9% higher than that by traditional hydro-distillation (HD) method (0.27 ± 0.013% g/g), and the time and energy consumption were 53.33% and 18.62% of the HD method, respectively. The results of GC-MS showed that the contents of main substances in the essential oils by EP-ME method were remarkably increased, including hexadecanoic acid methyl ester (+11.05%), 9Z,12Z,15Z-octadecatrienoic acid methyl ester (+5.26%), (Z)-9-octadecenoic acid methyl ester (+3.85%), methyl hexadic-9-enoate (+3.11%), methyl linoleate (+2.68%), linalool (+1.83%), and methyl stearate (+1.18%). In vitro activity results revealed that EOFs extracted using EP-ME method not only had certain anti-microorganism activity, but also possessed good cholinesterase inhibition activity, and its semi-inhibition concentrations (IC50) against acetyl-cholinesterase and butyrylcholinesterase were 2.48 and 2.31 mg/mL, respectively. Therefore, the EP-ME method was a kind of green and effective method for extracting high-quality essential oils from Dolichos lablab flowers.

A novel strategy for obtaining essential oil and flavonoids from Thymus vulgaris L. using polyethylene glycol-ultrasonic pretreatment followed by microwave hydrodistillation and extraction

As a medicinal plant with high economic value, the green and efficient separation of the main components (essential oil (EO) and flavonoids) from Thymus vulgaris L. can enhance its application prospects. The present study developed a polyethylene glycol-ultrasonic pretreatment followed by microwave hydrodistillation and extraction (PEG-U-MHDE) technique to distill EO and extract flavonoids simultaneously. The parameters involved in the PEG-ultrasonic pretreatment and microwave irradiation processes were investigated using single factor and BBD experiments, from which 25 % PEG200/400/600 (1:1:1, v/v/v) was found to have the highest extraction ability. Under the optimal conditions, the yield of EO, apigenin, and baicalein was 3.72 ± 0.15 μL/g, 0.76 ± 0.03 mg/g, and 0.96 ± 0.03 mg/g, respectively. The PEG-U-MHDE showed good stability, recovery, and repeatability for apigenin and baicalein. In addition, the separation efficiency of EO, apigenin, and baicalein obtained by PEG-U-MHDE was 0.19 μL/g/min, 37.85 μg/g/min, and 48.03 μg/g/min, respectively, and the EO contained 81.77 % oxygenated compounds, which were higher than other reference methods. The inhibition rate of EO (concentration of 0.5 μL/mL) against the agricultural pathogenic fungus (Fusarium graminearum) was 36.65 ± 1.28 %, which was speculated to be closely related to its main oxygenated compounds (thymol and carvacrol). In general, PEG-U-MHDE has the advantages of short time and high efficiency, and can realize the simultaneous separation of volatile EO and non-volatile components, which provides a theoretical basis for the comprehensive utilization of natural medicinal plants and crops.

Melatonin Dose-Mediated Increment in Growth, Floral Production, Essential Oils Yield and Composition in Marigold

Melatonin Dose-Mediated Increment in Growth, Floral Production, Essential Oils Yield and Composition in Marigold

Comparative Studies of Chemical Composition and Biological Activity of Juniperus Communis L. Essential Oil From Different Localities in the Republic of Serbia

Abstract This work aims to determine the chemical composition of Juniperus communis (J. communis) essential oil from different localities in the Republic of Serbia and examine its antimicrobial and antioxidative effects together with chemometric analysis and principal component analysis. Essential oils were extracted via hydro distillation from the fruits of J. communis gathered from four different habitats in Serbia. Extraction yields ranged from 1.56 % in the sample from Bavanište to 1.98% in the sample from Mačkat. A total of 23 compounds in the four essential oil samples were identified by Gas Chromatography-Mass Spectrometer (GC-MS). The dominant compounds were α-pinene (32.68–51.10 %), β-phellandrene (6.43–24.77 %), and β-pinene (9.84–14.09 %). Compared with the other ecological factors, precipitation showed a strongly positive correlation (0.871) with essential oil yields. The four samples could be classified into two clusters based on the variance in their components. All the essential oils samples showed bioactivities. Among them, the essential oil from the Mačkat sample showed the best ABTS radical scavenging activity (IC50=237.74 μg/ml), DPPH radical scavenging activity (IC50=308.83 μg/ml) and antimicrobial activities. Consequently, the essential oil extracted from Mačkat has the potential for commercial viability in the food, cosmetic, or medical fields.

The effects of spraying with onion and garlic extracts on the growth of the plant Anethum graveolens L. and its antioxidant effectiveness

This experiment was conducted during the 2022–2023 agricultural season in a mixed clay soil at one of the fields of the Faculty of Agriculture, Basra University. The aim of the experiment was to investigate the effect of spraying dill plants (Anethum graveolens L) with aqueous extracts of onion and garlic on their growth. The plants were sprayed with garlic aqueous extract at three concentrations (0, 20, 30 g L-1) and onion aqueous extract at three concentrations (0, 15, 25 g L-1), with three applications at a 15-day interval between each spray. The experiment was designed using a Randomized Complete Block Design (RCBD). The obtained results showed that the plants sprayed with garlic aqueous extract exhibited significant improvements in most characteristics, except for the fruit content of total dissolved carbohydrates and the yield of fruits from volatile oil. Specifically, the plants sprayed with a concentration of 30 g L-1 outperformed the other two concentrations in terms of plant height (cm), number of branches per plant, and 1000-seed weight for each experimental unit. On the other hand, the plants sprayed with a concentration of 20 g L-1 significantly outperformed in terms of floral inflorescence number per plant and seed yield. Additionally, the plants sprayed with a concentration of 30 g L-1 had the highest chlorophyll content and antioxidant effectiveness of dill leaves (%). However, spraying with garlic extract did not have a significant effect on the fruit content of total dissolved carbohydrates and the yield of fruits from volatile oil. Regarding the plants sprayed with onion extract, they showed overall superiority in most traits, except for the chlorophyll content of the leaves. Specifically, the plants sprayed with a concentration of 15 g L-1 significantly excelled in plant height, while the plants sprayed with a concentration of 25 g L-1 outperformed in terms of floral inflorescence number per plant and seed yield. The plants sprayed with a concentration of 25 g L-1 also had the highest content of total dissolved carbohydrates in fruits and the highest antioxidant effectiveness of dill leaves and seeds (%). However, the plants sprayed with a concentration of 15 g L-1 had the highest yield of volatile oil. The interaction between the two factors (garlic and onion extracts) had a significant effect on all studied traits, except for the chlorophyll content of the leaves.

Chemical Profiling of Essential Oils from Main Culinary Plants—Bay (Laurus nobilis L.) and Rosemary (Rosmarinus officinalis L.) from Montenegro

The aim of the research was to determine the yield, chemical composition and free radical-scavenging activity of the essential oils (EOs) in the leaves and fruit of wild-grown bay (Laurus nobilis L.) and rosemary(Rosmarinus officinalis L.)from the Montenegro coast. The bay essential oil (BEO) yield was 0.88% in fruit and 2.65% in the leaves. The rosemary essential oil (REO) yield was 1.30%. BEOs obtained from the leaves and fruit display different compositions. Fifty components were identified in leaf BEO, with 1,8-cineole (39.4%), linalool (13.9%), α-terpinyl acetate (11.2%), sabinene (6.7%) and methyl eugenol (5.7%) being the most abundant ones. Fifty-five components were isolated from fruit BEO, with 1,8-cineole (34.2%), α-pinene (6.6%), sabinene (6.1%) and β-bisabolene (5.8%) being the main components. Twenty-seven components were identified in leaf REO, with the main components being camphor (31.9%), borneol (12.2%), 1,8-cineole (11.3%) and myrcene (10.7%). The BEOs isolated from leaves (EC50 value of 1.43 mg/mL) and fruit (EC50 value of 3.74 mg/mL) showed stronger antioxidant activity than REO (EC50 value of 5.00 mg/mL) during an incubation time of 20 min. The results obtained for the bay and rosemary EOs from Montenegro highlight their potential not only for culinary purposes but also as a source of antioxidants and for use in the food and pharmaceutical industries.

Effect of kaolin on productivity, anatomical and biochemical responses to water deficit in Pelargonium graveolens grown in sandy soil

The objective of this study was to examine the response of geranium plants to different irrigation levels (100%, 80%, and 60% based on ETo) and Kaolin application rates (0, 100, 200 and 300 ppm) during 2022 and 2023 seasons, at Aly Mobarak Experimental Farm, Horticulture Research Station, located at El-Bustan site, El-Behiera Governorate, Egypt, by using a two-way factorial analysis experimental design. The results revealed that water deficit significantly reduced most studied traits. Irrigation level at 60% based on ETo exhibited poorest performance on growth parameters and decreased fresh yield and essential oil yield by 27.77% 10.73%, respectively as compared with full irrigated plants. However, foliar application of kaolin at 200 and 300 ppm led to increasing biomass accumulation by 28.51, 26.16%, and essential oil yield by 79.51, 89.95%, respectively, as compared with untreated plants grown under the same level of water deficit (60% based on ETo). GC–MS analysis of essential oil showed that water deficit and kaolin application increased geraniol/citronellol ratio and consequently improved oil quality. Results highlight the positive influence of water deficit and kaolin rates on the development and performance of anatomical parameters. Enzymes assay in leaves revealed in an increase superoxide dismutase (SOD) and peroxidase (POD) activities, and decreased in catalase (CAT) activity under water deficit. As for WUE at 60%, followed by 80% based on ETo recorded excellent response for geranium plants which led to more water saving. So, it could be concluded that foliar application of kaolin at 200 and 300 ppm obtained the optimal characteristics of geranium plants under experimental conditions. In particular, essential oil yield and productivity.

Irrigation Effects on Volatile Profile and Essential Oil Yield of Guayule During Flowering

Irrigation Effects on Volatile Profile and Essential Oil Yield of Guayule During Flowering

The influence of soil properties on essential oil components of Hypericum perforatum L. growing in Turkey

Hypericum perforatum L. is a medicinally and commercially important plant with a long history of traditional use. It is used for conditions such as depression, wound healing, ulcers, and the common cold. The medicinal properties of H. perforatum are primarily attributed to its essential oil (EO). Various soil conditions, such as pH, soil texture (sand, silt, and clay content), nutrient content (potassium, magnesium, calcium, sodium, iron, copper, zinc, and manganese), and organic matter, can influence the composition and concentration of EO in plants. In this study, these conditions were investigated aiming to understand the influence of soil’s physical and chemical properties on the EOs extracted from H. perforatum collected from various localities. Dried aerial parts of H. perforatum from 20 different locations in Eskişehir, Turkey, were hydrodistilled using a Clevenger-type apparatus. The EO components were analyzed using GC-FID and GC-MS systems. Soil samples were collected from the same 20 local habitats and subjected to physical and chemical analyses. The results were then correlated with the main EO components. GC-MS results identified 119 compounds, representing 71-96.6% of the volatiles in all samples. The findings revealed that specific soil parameters, including Mg, Ca, dust, lime, clay, and pH, had a significant impact on the yield and chemical composition of H. perforatum EO, particularly affecting the levels of α-pinene, caryophyllene oxide, 1-dodecanol, and 1-tetradecanol. Further research is needed to fine-tune these soil parameters in conjunction with other ecological factors to maximize the qualitative and quantitative yield of EO from H. perforatum.

Effect of Harvesting Stages on Herbage and Essential Oil Yield of Rosemary (Rosmarinus Officinalis L.) under Northern Dry Zone of Karnataka, India

Aim: To study the effect of different phenological stages of harvesting on the yield and quality of rosemary. Study Design: Fisher’s method of ANOVA. Place and Duration of Study: Department of Plantation, Spices, Medicinal and Aromatic Crops, College of Horticulture, Bagalkot, Karnataka during rabi 2023-24. Methodology: The experiment was laid out in Randomized Complete Block Design with five replications, comprising five different stages of harvesting namely vegetative stage, flower initiation stage, fifty per cent flowering stage, full bloom stage and seed setting stage. Results: The maximum mean fresh herbage yield (589.79 g plant-1, 14.74 kg plot-1 and 13.54 t ha-1) and dry herbage yield (308.40 g plant-1, 7.71 kg plot-1 and 7.08 t ha-1) were noticed at the seed setting stage. Whereas the superior essential oil content (1.51 %) was viewed at the vegetative stage. The greater essential oil yield (129.34 kg ha-1) was observed at the full bloom stage, which was on par with the seed setting stage (127.20 kg ha-1) and fifty per cent flowering stage (118.11 kg ha-1). Conclusion: Fifty per cent flowering stage can be considered as suitable harvesting stage of rosemary under northern dry zone of Karnataka.

Phytochemical variability in essential oils of Juniperus communis var. saxatilis populations grow wild in western Himalaya, India

Needle and berry samples of Juniperus communis L. var. saxatilis Pall. were sampled separately during post rainy season to comparatively investigate the essential oil (EO) yield and phytochemical variability in eight populations grow wild in western Himalaya, India. The EOs obtained from air-dried needle and berry samples separately by hydrodistillation method using Clevenger type apparatus varied in yield with geographic origin of populations, ranged between 2.5-3.4% and 1.8-2.8% (v/w, dried weight basis), respectively. GC-MS analysis of EO profiles resulted in identification of a total ninety-four phytochemicals, representing over 95% of total oil content. Both, needle as well as berry EO samples were dominated by monoterpene hydrocarbons α-pinene (18.52-30.65% and 14.31-27.37%), D-limonene (17.01-28.96% and 15.80-29.70%), β-myrcene (3.74-5.59% and 4.12-14.23%), followed by sesquiterpene hydrocarbons β-elemene (0.86-4.13% and 0.77-3.65%) and germacrene D (0.27-2.57% and 0.20-6.15%), respectively. The oxygenated sesquiterpenes α-cadinol (0.34-5.90% and to 5.63%) and α-bisabolol (to 3.39 and 0.95-6.71%) constituted the third most abundant group of terpenes while oxidized monoterpenes with α-terpineol (0.73-2.17% and 0.10-3.51%) and α-terpinyl acetate (2.10-4.76% and 0.05-3.54%) were the least dominant group. The principal component and hierarchical cluster analysis indicated that selective local environmental forces driving the microhabitat conditions appeared to be linked to high variability in essential oil composition of different common Juniper populations instead of their geographical proximity. The present study revealed that common Juniper essential oils from western Himalaya, India fulfil minimum requirements of European Pharmacopoeia and warrants its further exploitation as a natural resource of commercial significance for dietary and therapeutic applications.

Effect of Magnesium Sulfate and Rhizosphere Microorganisms on the Growth and Biosynthesis of Cymbopogon nardus L. Essential Oil

Background: Citronella oil from Cymbopogon nardus L. is used in various fields, including health, industry and pharmaceuticals. Efforts to increase the content and quality of essential oils in this research were made with the application of magnesium sulfate. Rhizosphere microorganisms, which act as biological fertilizers, are applied to assist in the absorption of nutrients. This research aims to determine the interaction between the type of rhizosphere microorganisms and the dose of MgSO4 on growth, essential oil yield and essential oil content in C. nardus. Methods: The research was carried out from February to August 2023. The research used a randomized block design arranged factorially with three replications. The first factor is the type of rhizosphere microorganisms (without RM, PGPR and AMF) and the second factor is the MgSO4 fertilizer dose (0, 190, 285 and 280 kg ha-1). Result: Providing MgSO4 fertilizer can increase the growth and yield of essential oils of C. nardus. The application of PGPR and AMF can increase efficiency of MgSO4 fertilization. Treatment without administering rhizosphere microorganisms required a higher dose of MgSO4 compared to PGPR and AMF treatments. To increase growth variables and essential oil quality, treatment without rhizosphere microorganisms requires MgSO4 of 380 kg ha-1, while PGPR and AMF only require MgSO4 at a dose of 190-285 kg ha-1.

Analysis of the Effects of Organic and Synthetic Mulching Films on the Weed, Root Yield, Essential Oil Yield, and Chemical Composition of Angelica archangelica L.

Angelica archangelica L. (Garden angelica) is a medicinal and aromatic plant from the Apiaceae family, originating from North Europe (Iceland, Greenland, and Scandinavian countries). A. archangelica is commonly used in traditional medicine to treat anxiety, insomnia, stomach and intestinal disorders, skin conditions, respiratory problems, and arthritis. This plant is generally cultivated for its root and seed where the essential oil (EO) is concentrated the most. Angelica archangelica cultivation has a lot of challenges but the main one is weed control; so, the aim of this study was to investigate the influence of four different mulch types as non-chemical weed control measures on weediness, fresh root yield, and EO chemical composition and yield from A. archangelica roots. A field trial was conducted with the following six treatments: two organic mulches, two synthetic mulches, and two controls (regular hand-weeded and weeded). The results show that the most present weeds were Ambrosia artemisiifolia, Chenopodium album, Polygonum aviculare, and Polygonum lapathyfolium, but synthetic mulch foils achieved the best weed suppression (100%). These fields also achieved the highest fresh root yield in both of the experimental seasons. The highest EO yield was detected with agrotextile mulch foil at season I (0.41%, v/w) and with the weeded control (0.51%, v/w) at season II, but dominant components at both seasons were α-pinene and β-phellandrene. The results suggest that the agrotextile black and silver–brown mulch foils achieved complete weed suppression, but the agrotextile black mulch foil had a better effect on fresh root yield, EO yield, and its chemical composition.

Comparative Study of Essential Oils Extracted From Foeniculum vulgare Miller Seeds Using Hydrodistillation, Steam Distillation, and Superheated Steam Distillation

ABSTRACTFoeniculum vulgare Miller is a highly valued aromatic and nutritious plant. The unique compositions of its essential oil make it more valuable in the flavor, fragrance, and medicinal industries. However, the potential of superheated steam distillation for obtaining essential oils from its seeds has not been explored in detail. This study assessed the composition, yield, antimicrobial, and antioxidant activities of essential oils distilled from F. vulgare seeds using traditional hydrodistillation, steam distillation, and superheated steam distillation. Superheated steam distillation resulted in the maximum quantity of essential oil (5.24%) compared to steam (3.47%) and hydrodistillation (2.47%). Trans‐anethole, fenchone, estragole, and limonene were the main identified by GC–MS analysis in the essential oils, and these compounds were abundant in the essential oil produced by superheated steam distillation. Essential oil distilled by superheated steam distillation presented the highest antibacterial activity against Staphylococcus aureus, Pastrulla multocida, Bacillus subtilis, and Escherichia coli. The highest antifungal activity against Aspergillus niger, Fusarium solani, Aspergillus flavus, and Alternaria alternate was also demonstrated by the same essential oil. These findings demonstrated the potential of superheated steam distillation as a highly effective and efficient technique for distilling high‐quality essential oils from Foeniculum vulgare Miller seeds. It is suitable for various applications in the food, cosmetic, and pharmaceutical industries.

Quality Characteristics and Essential Oil Properties of Thymus capitatus, Mentha piperita, and Sideritis cypria Dried under Different Conditions.

The drying of medicinal and aromatic plants (MAPs) is one of the main preservation methods for these products that can prolong their shelf life, if performed properly. The current study aimed to examine the effects of different drying conditions (sun, shade, and oven drying at 42 °C) on the quality characteristics of Thymus capitatus, Mentha piperita, and Sideritis cypria; their essential oil (EO) yield; and their biological properties (antioxidant and antibacterial activities). According to the results of the current study, oven drying resulted in faster moisture loss for all investigated species and slightly darker products. For T. capitatus, sun drying resulted in higher EO carvacrol content, whereas EOs obtained from shade and oven drying (at 42 °C) presented high total phenolic content and great antimicrobial activity. For M. piperita, shade drying resulted in a higher EO yield and higher iso-menthone content, whilst the EO obtained from oven-dried mint plants presented great antibacterial activity against the investigated foodborne pathogens. S. cypria plants dried in an air-ventilated oven produced an EO rich in β-caryophyllene and α-pinene, which also presented great antioxidant and antibacterial activity. The findings of the current study indicate that traditional drying methods, such as sun and shade, can result in good-quality dried MAPs that can yield EOs with significant biological activities, along with minimum energy consumption and lower carbon dioxide production (lower environmental carbon footprint), as opposed to oven drying. However, the drying-process duration could be a limitation at the industrial scale.