Dill Ether Research Articles

Evaluation of a dill (Anethum graveolens L.) gene bank germplasm collection using multivariate analysis of morphological traits, molecular genotyping and chemical composition to identify novel genotypes for plant breeding.

Dill (Anethum graveolens L.) is an aromatic herb widely used in the food industry, with several commercial cultivars available with different qualitative characteristics. Commercial cultivars are usually preferred over landraces due to their higher yield and also the lack of improved landraces than can be commercialized. In Greece, however, traditional dill landraces are cultivated by local communities. Many are conserved in the Greek Gene Bank and the aim here was to investigate and compare the morphological, genetic, and chemical biodiversity of twenty-two Greek landraces and nine modern/commercial cultivars. Multivariate analysis of the morphological descriptors, molecular markers, and essential oil and polyphenol composition revealed that the Greek landraces were clearly distinguished compared with modern cultivars at the level of phenological, molecular and chemical traits. Landraces were typically taller, with larger umbels, denser foliage, and larger leaves. Plant height, density of foliage, density of feathering as well as aroma characteristics were desirable traits observed for some landraces, such as T538/06 and GRC-1348/04, which were similar or superior to those of some commercial cultivars. Polymorphic loci for inter-simple sequence repeat (ISSR) and start codon targeted (SCoT) molecular markers were 76.47% and 72.41% for landraces, and 68.24% and 43.10% for the modern cultivars, respectively. Genetic divergence was shown, but not complete isolation, indicating that some gene flow may have occurred between landraces and cultivars. The major constituent in all dill leaf essential oils was α-phellandrene (54.42-70.25%). Landraces had a higher α-phellandrene and dill ether content than cultivars. Two dill landraces were rich in chlorogenic acid, the main polyphenolic compound determined. The study highlighted for the first-time Greek landraces with desirable characteristics regarding quality, yield, and harvest time suitable for breeding programs to develop new dill cultivars with superior features.

Machine Learning Algorithms Applied to Semi-Quantitative Data of the Volatilome of Citrus and Other Nectar Honeys with the Use of HS-SPME/GC-MS Analysis, Lead to a New Index of Geographical Origin Authentication.

The scope of the current study was to monitor if semi-quantitative data of volatile compounds (volatilome) of citrus honey (ch) produced in different countries could potentially lead to a new index of citrus honey authentication using specific ratios of the identified volatile compounds in combination with machine learning algorithms. In this context, the semi-quantitative data of the volatilome of 38 citrus honey samples from Egypt, Morocco, Greece, and Spain (determined by headspace solid phase microextraction coupled to gas chromatography mass spectrometry (HS-SPME/GC-MS)) was subjected to supervised and unsupervised chemometrics. Results showed that honey samples could be classified according to the geographical origin based on specific volatile compounds. Data were further evaluated with additional nectar honey samples introduced in the multivariate statistical analysis model and the classification results were not affected. Specific volatile compounds contributed to the discrimination of citrus honey in different amounts according to geographical origin. These were lilac aldehyde D, dill ether, 2-methylbutanal, heptane, benzaldehyde, α,4-dimethyl-3-cyclohexene-1-acetaldehyde, and herboxide (isomer II). The numerical data of these volatile compounds was summed up and divided by the total semi-quantitative volatile content (Rch, Karabagias-Nayik index) of citrus honey, according to geographical origin. Egyptian citrus honey had a value of Rch = 0.35, Moroccan citrus honey had a value of Rch = 0.29, Greek citrus honey had a value of Rch = 0.04, and Spanish citrus honey had a value of Rch = 0.27, leading to a new hypothesis and a complementary index for the control of citrus honey authentication.

Application of growth promoting hormones alters the composition and antioxidant potential of dill essential oil under salt stress

The performance of dill plant may be affected by adverse environments such as salinity. Thus, this research was designed to evaluate changes in chemical composition and antioxidant activity of seed essential oil of dill (Anethum graveolens L.) in response to salinity (0, 5, 10 and 15 dS/m) and 1 mM of each hormonal treatments (gibberellic acid, salicylic acid, and cytokinin). Salicylic acid (SA) reduced Na+ content of roots and leaves by 15.4%, 30.9% and 12.4%, 24.3%, but enhanced K+ content by 29.8%, 51.6% and 76.6%, 73.4% under moderate and severe salinities, respectively. Essential oil yield was enhanced with progressing seed filling, despite decreasing essential oil percentage. Percentage of essential oil was increased under low and moderate salinities. Hormonal treatments, particularly SA enhanced seed mass and essential oil percentage, leading to enhanced essential oil yield. The amounts of most constituents were enhanced under moderate salinity. Foliar spray of SA and CK (cytokinin) increased almost all essential oil components, except dill ether and dill apiole, while the GA3 (gibberellic acid) treatment reduced most of the constituents. The α-fenchol was only induced by salt stress. The β-pinene, 1-terpineol, cryptone, oxypeucedanin hydrate, α-thujene and P-α-dimethylstyrene were also specifically synthesized in SA treated plants under salinity. The highest TPC (total phenolic content) and antioxidant activity were recorded for essential oil of SA treated plants at mass maturity under moderate salinity. In general, the SA spray was the most effective treatment for improving essential oil quantity and quality of dill plants.

Chemical Composition and Biological Activities of Anethum graveolens L. Essential Oil from Algeria

Anethum graveolens commonly known as dill plant is a very important shrub which is widely acknowledged in traditional and modern medicine for its capacity to treat colic pain and flatulence. The purpose of this work is the study of the chemical composition and the evaluation of antibacterial, antifungal and antioxidant activities of A. graveolens essential oil. The samples were collected from the chellal region in Algeria and submitted to hydrodistillation. The essential oil extracted was analyzed by GC and GC/MS. The antibacterial and antifungal activities were tested by the disc diffusion method; seven bacteria and four phytopathogenic fungi were used. The evaluation of the antioxidant activity was carried out by the 2,2-diphenyl-1-picrylhydrazyl scavenging method. The results of the GC and GC/MS analysis allowed the identification of 22 components with carvone(34.33%), α-phellendrene (22.03%), dill ether (18.84%), limonene (6.93%) and dill apiol (5.01%) as major components. The results of the disc difusion method show that Anethum graveolens essential oil exhibits strong antibacterial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and moderate antifungal activity against Fusarium graminum and Alternaria alternata. The pure essential oil showed a moderate antioxidant activity with inhibition percentages of 49.93 ± 4.58%. This study highlights the importance of chemical constituents of A. graveolens essential oil which possesses important pharmacological effects on different pathogenic strains and could be used as substitute for synthetic antimicrobial drugs in pharmaceutical industries.

Formation of Diastereomeric Dihydromenthofurolactones by Cystostereum murrayi and Aroma Dilution Analysis Based on Dynamic Headspace Extraction.

Submerged cultures of the basidiomycota Cystostereum murrayi emit an intensive coconut-like, sweetish, and buttery smell. For identification of the key aroma compounds, an aroma dilution analysis using dynamic headspace was performed by adjusting the split ratio of the GC inlet system. Flavor dilution (FD) factors varied from 22 up to ≥218, whereby the largest class of compounds represented terpenoids, including two rare stereoisomers of 3,6-dimethyl-2,3,3a,4,5,7a-hexahydrobenzofuran (dill ether, ee ≥ 99.9). By means of nuclear magnetic resonance spectroscopy, the substances with the highest FD factors (29, 212, and 218) were identified as diastereomers of 3,6-dimethyl-3a,4,5,6,7,7a-hexayhydro-3H-1-benzofuran-2-one (dihydromenthofurolactone) and as its corresponding C3-unsaturated lactone. The latter two compounds have not been described for Cystostereum murrayi or for any other basidiomycota previously. Supplementation studies using 2-13C-d-glucose indicated that these lactones as well as the two stereoisomers of dill ether and other terpenoids were formed de novo by the fungus.

Chemical components of essential oils and biological activities of the aqueous extract of Anethum graveolens L. grown under inorganic and organic conditions

BackgroundIn sustainable agriculture, the use of farmyard manure (FYM) is of great interest to environmental security and is effective as a good nitrogen source for sustainable crop production. Therefore, determining the effective doses of FYM that will be an alternative to chemical fertilizers, is also important to improve soil fertility and produce healthy products. This study aimed to determine the effects of FYM and ammonium nitrate (AN) fertilizers on the biological value and essential oil content of dill (Anethum graveolens L.).MethodsDifferent doses FYM (7.5, 10, 12.5 and 15 t ha−1) and AN (30, 60, 90 and 120 kg ha−1) were applied by sowing and compared to a control group (no manure). We evaluated the chemical constituents as well as the biological activities of dill herbs and seeds growing at various doses of FYM and AN fertilizers.ResultsThe most abundant components of essential oils were found to be dill apiole (11.96 ± 0.83 and 18.65 ± 1.89%) and carvotanacetone (15.90 ± 2.34 and 21.76 ± 1.62%) in the leaves and seeds, respectively. Limonene (9.01 ± 1.11%), 4-isopropyltoluen (8.24 ± 0.89%), dill ether (9.13 ± 1.12%) and mycrene (7.44 ± 0.68%) were major essential oils components in herbs. The highest concentration of the essential oil components was determined as 12.5–15 t ha−1 in FYM and 90 AN applications. From the effective concentration (EC50) of the samples, it was seen that 60 kg ha−1 AN infusion, 120 kg ha−1 AN decoction as well as 7.5 t ha−1 FYM and 10 t ha−1 FYM essential oils had the highest DPPH, ABTS+ and superoxide anion radical scavenging activity as shown by the lowest value of EC50 compared to the control. Although the antioxidant activities of the samples were significantly lower than those of the reference antioxidant gallic acid, it was evident that they did show the antioxidative potential for hydrogen and a single electron donor activities, thus could serve as free radical scavengers, and act as reductant. In particular, the highest total phenolic content (18.36 ± 0.35 mg g−1) was found in the infusion extract after applying the 60 kg ha−1 AN fertilizer. Essential oils extracted from the seeds also exhibited strong antibacterial activity against Staphylococcus epidermidis, Enterococcus faecalis, and Pseudomonas aeruginosa. The highest antibacterial activity against all tested microbial species was observed with the 10 t ha−1 FYM application.ConclusionThe findings of the study suggest that the application of FYM has promising effects on dill leaf, seed, and herb and can be considered as a suitable substitute for chemical fertilizers when growing dill, a plant with increasing importance and demand.

The Application of Essential Oil Vapors at the End of Vacuum Cooling of Fresh Culinary Herbs Promotes Aromatic Recovery.

Aroma is an important quality parameter of fresh culinary herbs that may be highly affected after postharvest treatments. The innovative technology of vapor essential oil (EO) application under vacuum conditions may recover aroma lost during the postharvest processing of plant products like aromatic herbs. Hence, this study assessed the aroma recovery effect of vapor EOs applied during vacuum cooling on curly parsley and dill. The volatile organic compounds (VOCs) profiles of these aromatic herbs were studied by static headspace solid-phase microextraction (SPME), and the VOCs sorption kinetics onto the SPME stir-bar coating were modeled by the Baranyi model. At the pilot plant scale, the total VOCs contents of parsley and dill (whose extractability was increased by 10–20% after a single vacuum process) were enhanced by 4.5- and 2-fold, respectively, when vapor EOs were applied. In particular, 1,3,8-p-menthatriene and carvone (parsley) increased by 18.7- and 7.3-fold, respectively, while dill ether (the characteristic VOC of dill) augmented by 2.4-fold after vapor EOs were applied under vacuum conditions. The aroma recovery of culinary herbs was successfully validated at an industrial level in an installation developed by our group to apply vapor EOs within a vacuum cooling system, reaching total VOC recoveries of 4.9- and 2.3-fold in parsley and dill, respectively.

Comparative Chemical Composition of Essential Oils in Dill (Anethum graveolens L.) Ecotypes: Focus on Univariate and Factor Analysis

Anethum graveolens L. is a vegetable-aromatic medicinal herb of Apiaceae family and cultivated in different parts of the world including Iran. The aim of this study was to study the chemical composition of essential oils in four Iranian dill ecotypes. The extracted essential oils compositions were different in the ecotypes so that 38, 27, 25, and 24 volatile constituents were identified in Ardabil, Isfahan, Mashhad, and Kerman ecotypes, respectively. Eighteen compounds such as Toluene, α-thujene, camphene, sabinene, β-pinene, β-myrcene, α-phellandrene, α-terpinene, β-phellandrene, undecane, sabinol, dill ether, carvacrol, germacrene D, dill apiole, neophytadiene, hexahydrofarnesyl acetone, and phytol were recognized in all ecotypes but in different amounts. Analysis of variance showed the significancy of α-thujene, β-pinene, β-myrcene, α-phellandrene, β-phellandrene, undecane, dill ether, sabinol, germacrene D, dill apiole, neophytadiene, and hexahydrofarnesyl acetone at 0.001 probability levels. Means comparison of significant compounds showed highest mean values for β-pinene, undecane, germacrene D, neophytadiene, hexahydrofarnesyl acetone, and phytol in Ardabil ecotype; α-thujene, β-myrcene, β-phellandrene, and dill ether in Mashhad ecotype; and α-phellandrene, sabinol, and dill apiole in Kerman ecotype. Factor analysis indicated that three main and independent factors accounted for 100% of the total variance. The first, second, and third factors with 47.5, 31.9, and 20.63 % of variance included 9, 6, and 4 compounds, respectively. The knowledge of essential oil compositions of the studied ecotypes could be useful to choose the appropriate for breeding purposes based on phytochemical diversity or for use in pharmaceutical and food industries for extraction of special compounds.

Integration of non-target metabolomics and sensory analysis unravels vegetable plant metabolite signatures associated with sensory quality: A case study using dill (Anethum graveolens)

Using dill (Anethum graveolens L.) as a model herb, we reveal novel associations between metabolite profile and sensory quality, by integrating non-target metabolomics with sensory data. Low night temperatures and exposure to UV-enriched light was used to modulate plant metabolism, thereby improving sensory quality. Plant age is a crucial factor associated with accumulation of dill ether and α-phellandrene, volatile compounds associated with dill flavour. However, sensory analysis showed that neither of these compounds has any strong association with dill taste. Rather, amino acids alanine, phenylalanine, glutamic acid, valine, and leucine increased in samples exposed to eustress and were positively associated with dill and sour taste. Increases in amino acids and organic acids changed the taste from lemon/grass to a more bitter/pungent dill-related taste. Our procedure reveals a novel approach to establish links between effects of eustressors on sensory quality and may be applicable to a broad range of crops.

A decisive strategy for monofloral honey authentication using analysis of volatile compounds and pattern recognition techniques

In an effort to determine some undisputed markers of botanical origin, the volatile profile of Hellenic monofloral honeys was investigated using gas chromatography coupled to mass spectrometry (GC–MS) in combination with headspace solid phase microextraction (HS-SPME). Different varieties of honey (citrus, fir, pine, and thyme) were analyzed and semi-quantitative data of volatile compounds originating from 82 samples were subjected to multivariate analysis of variance (MANOVA).Results showed that by using only 9 volatiles [dill ether (0.012 mg kg−1), alpha-4-dimethyl-3-cyclohexene-1-acetaldehyde (0.030 mg kg−1), acetic acid ethyl ester (0.030–0.173 mg kg−1), octanoic acid ethyl ester (0.004–0.547 mg kg−1), methylanthranilate (0.030 mg kg−1), 2,2,4,6,6-pentamethyl-heptane (0.005–0.057 mg kg−1), phenylacetaldehyde (0.014–1.248 mg kg−1), cis-linalool oxide (0.007–0.010 mg kg−1), lilac aldehyde (isomer III) (0.032–0.437 mg kg−1)] honeys could be classified correctly according to botanical origin. The correct prediction rates were 93.9%, 96.8%, and 89.5%, based on the cross-validation method and using stepwise linear discriminant analysis, training and holdout partitions (k-nearest neighbors analysis), respectively. The efficiency of the discrimination model was confirmed further by application to mixed floral honeys and the use of the aforementioned consecutive pattern recognition techniques. The use of specific volatile compounds in combination with statistical tools may constitute a fast, decisive and accurate strategy for monofloral honey authentication.

Biosynthesis of Stereoisomers of Dill Ether and Wine Lactone by Pleurotus sapidus.

The white-rot fungus Pleurotus sapidus (PSA) biosynthesizes the bicyclic monoterpenoids 3,6-dimethyl-2,3,3a,4,5,7a-hexahydrobenzofuran (dill ether) (1) and 3,6-dimethyl-3a,4,5,7a-tetrahydro-1-benzofuran-2(3H)-one (wine lactone) (2). Submerged cultures grown in different media were analyzed by gas chromatography-mass spectrometry. The stereochemistry of the formed isomers was elucidated by comparing their retention indices to those of reference compounds by enantioselective multidimensional gas chromatography. The basidiomycete produced the rare (3R,3aR,7aS) and (3S,3aR,7aS) stereoisomers of dill ether and wine lactone. Kinetic analyses of the volatilome and bioprocess parameters revealed that the biosynthesis of the bicyclic monoterpenoids correlated with the availability of the primary carbon source glucose. Spiking the media with 13C-labeled glucose demonstrated that the compounds were produced de novo. Supplementation studies i.a. with isotopically labeled substrates further identified limonene and p-menth-1-en-9-ol as intermediate compounds in the fungal pathways. PSA was able to biotransform all enantiomeric forms of the latter compounds to the respective isomers of dill ether and wine lactone.

Nanoemulsion of Dill essential oil as a green and potent larvicide against Anopheles stephensi.

Indiscriminate use of industrial larvicides causes environment pollution and resistance against the larvicides in mosquitoes. Essential oils (EOs) have many biological activities such as larvicidal effects which have been proposed as new alternatives for industrial ones. Many components of EOs are volatile, thus, should be formulated to retain their activity. Components of Dill EO were identified by GC-MS analysis. Larvicidal activity (LA) of bulk Dill EO (non-formulated) was evaluated against Anopheles stephensi in line with WHO guideline for lab tests. For the first time, nanoemulsions of Dill EO were prepared. Various nanoemulsions having fixed amounts of Dill EO 1.2%, comparable with lethal concentration (LC) at 90% of bulk Dill EO, were prepared having tween 20 (5-30%) with/out ethanol (5-30%). LA of two selected nanoemulsions were then evaluated and compared with that of bulk Dill EO. Five ingredients of oil, with high amounts, were identified as p-Cymenealpha (20.81%), alpha-Phellandrene (20.75%), Carvone (10.97%), Dill ether (9.88%), and cis-Sabinol (3.61%). LC of Dill EO at 50 and 90% were found as 38.8 and 65ppm, respectively, against 3rd and 4th instar larvae of An. stephensi (Beech-Lab strain). Particle size (PS) ranges of nanoemulsions were 10.7-1880.0nm. LA of optimum nanoemulsion (PS: 10.7nm) was significantly better than that of bulk Dill EO. The preparation showed stability against 200 times dilution during larvicidal tests and performed significantly better than the nanoemulsion which was not stable after dilution. To obtain improved efficiency against larvae using nanoemulsions of EOs, the nanoemulsion should be resistant against dilution. Such a stable and green nanoemulsion may be used as alternative to industrial larvicides.

Synthesis and olfactory evaluation of (8S)‐(−)‐p‐Mentha‐1,3‐dien‐9‐ol and some of its esters

Abstract(8S)‐(−)‐p‐Mentha‐1,3‐dien‐9‐ol (3) has been synthesized and fully characterized, using dill ether as the starting material. Dill ether is a common constituent of the essential oil of dill weed, Anethum graveolens L. In the first step, (8S)‐(−)‐p‐mentha‐1,3‐dien‐9‐yl acetate was prepared by treating dill ether with anhydrous magnesium bromide, followed by the addition of acetic anhydride. Hydrolysis of this mixture with potassium hydroxide led to the formation of alcohol 3, with p‐cymen‐9‐ol as the main by‐product. The chemical identity of compound 3 has been confirmed by GC/MS, IR, one‐ and two‐dimensional NMR. Chiral analysis has shown that it consists of enantiomerically pure (8S)‐(−)‐p‐mentha‐1,3‐dien‐9‐ol. This has been corroborated by selective oxidation of p‐mentha‐1,3,8‐triene found in the essential oil of curly leaf parsley, Petroselinum crispum (Mill.) Fuss., to give a racemic mixture of p‐mentha‐1,3‐dien‐9‐ol. Other esters (propionate, butyrate and valerate) of alcohol 3 have been prepared in a similar way by treating dill ether with the corresponding acid anhydride. Olfactory evaluation of alcohol 3 revealed a floral character while its esters gave a range of fruity and herbaceous notes.

Investigating Chemical Composition and Indications of Hydrosol Soft Drinks (Aromatic Waters) Used in Persian Folk Medicine for Women's Hormonal and Reproductive Health Conditions.

Hydrosol soft drinks in Persian nutrition culture are produced as side products of the essential oil industry to be used as safe remedies for treatment of some ailments. This study investigated hydrosols for women’s hormonal health conditions. Detailed information was gathered by questionnaires. Chemical constituents of these mono- or poly-herbal hydrosols were identified after liquid/liquid extraction and gas chromatography–mass spectrometry. Hierarchical cluster and K-means analysis (SPSS software) were used to find their relevance. A literature survey was also performed. In most cases, thymol, carvacrol, and carvone were the major constituents except for dill, white horehound, willow, Moderr, and yarrow hydrosols, whose their major components were dill ether, menthol, phenethyl alcohol, linalool, or camphor. Based on clustering methods, some similarities could be found in their constituents with some exceptions. None of them have been studied scientifically before. These investigations may lead to the development of some functional drinks or even new lead components.

Aroma constituents of shade-dried aerial parts of Iranian dill (Anethum graveolens L.) and savory (Satureja sahendica Bornm.) by solvent-assisted flavor evaporation technique

The aroma profile of shade-dried aerial part from Iranian dill (Anethum graveolens L.) and Savory (Satureja sahendica Bornm.) plants was analyzed by the gas chromatography–mass spectrometry (GC–MS) and gas chromatography–flame ionization detector (GC–FID). For the first time in these aromatic plants, the solvent-assisted flavour evaporation (SAFE) extraction method with dichloromethane was used prior to GC–MS. A total of 40 and 26 aroma compounds was identified in dill and savory. Dill contained 271.52 µg/g total amount of aroma compounds, which included terpenes (28), aldehydes (3), alcohol (1), acids (3), volatile phenols (3), ketone (1) and norisoprenoid (1). Savory possessed 10,547.16 µg/g total amount of aroma compounds, including terpenes (20), alcohol (1) and volatile phenols (5). Of all aroma compounds detected in both plants, terpenes were quantitatively the most dominant aroma volatiles. In the overall aroma volatiles, α-phellandrene (160.0 µg/g) together with sabinene (26.5 µg/g), d-carvone (16.2 µg/g), dl-limonene (12.3 µg/g) and dill ether (7.8 µg/g) in dill and γ-terpinene (6236.83 µg/g) along with carvacrol (3239.19 µg/g), α-pinene (267.08 µg/g), α-thujene (219.36 µg/g) and β-bisabolene (130.8 µg/g) in savory were the major compounds.

The effect of water deficiency and salinity on the growth and quality of fresh dill (Anethum graveolens L.) during autumn and spring cultivation

The aim of this experiment was to determine the response of dill (Anethum graveolens L.) towater deficiency and salinity. In spring, dill biomass decreased with increasing water deficiencydue to a reduction in the number and mean weight of leaves per plant. The concentrations ofchlorophyll, carotenoids, vitamin C and total phenolics within the leaves were unaffected bywater stress, but the Cl, Na and K content decreased. Salinity had no effect on plant growth inthe spring, except at the highest level (8 dS/m-1), where a decrease in biomass occurred. Thechlorophyll and total phenolics content of leaves rose in the autumn with increasing salinity,whereas vitamin C and carotenoids were unaffected. In spring, increasing salinity causedfluctuations in the chlorophyll and vitamin C content of the leaves and a decrease in totalphenolics. The concentrations of chlorophyll and antioxidants were higher in spring than inautumn at all levels of salinity. The essential oil content was also higher in the spring than in theautumn, irrespective of salinity. A relative decrease in dill ether within the herb oil underincreasing salinity was compensated for by an increase in α-phellandrene. In the flower oil,increasing salinity caused a decrease in the relative concentrations of both α-phellandrene anddill ether, which was compensated for by an increase in carvone. Overall, dill appears moreresistant to salinity than to water stress, but the season of cultivation has the most importanteffect on both yield and quality.

Irrigation dose and plant density affect the volatile composition and sensory quality of dill (Anethum graveolens L.).

Two independent field experiments were carried out to investigate the influence of (i) three irrigation treatments (ID0 = 1585 m3 ha-1 , considered as a control; ID1 = 1015 m3 ha-1 ; and ID2 = 2180 m3 ha-1 ) and (ii) three plant density treatments (PD0 = 5.56 plants m-2 , considered as a control; PD1 = 4.44 plants m-2 ; and PD2 = 7.41 plants m-2 ) on the production, volatile composition of essential oil, and sensory quality of dill. The highest plant yield was obtained with intermediate conditions of both irrigation dose (ID0) and plant density (PD0). The main compounds of the essential oil were α-phellandrene, dill ether and β-phellandrene. The highest irrigation dose (ID2) produced the highest concentrations of most of the main compounds: α-phellandrene (49.5 mg per 100 g), β-phellandrene (6.89 mg per 100 g) and limonene (2.49 mg per 100 g). A similar pattern was found for the highest plant density (PD2): α-phellandrene (71.0 mg per 100 g), dill ether (16.7 mg per 100 g) and β-phellandrene (9.70 mg per 100 g). The use of descriptive sensory analysis helped in reaching a final decision, and the dill plants with the highest sensory quality were those of the ID2 and PD0 treatments. The final recommendation is to use the irrigation dose ID2 and the plant density PD2 if the objective is to produce dill samples with the highest aromatic and sensory quality; however, if the only objective is to produce high amounts of dill, the best options are ID0 and PD0. © 2016 Society of Chemical Industry.

Volatile Composition of Essential Oils from Different Aromatic Herbs Grown in Mediterranean Regions of Spain.

Volatile composition of essential oils from dill, parsley, coriander, and mint were investigated at different harvest dates to determine the most suitable harvest time for each these herbs. Hydrodistillation (HD), using a Deryng system, was used for isolating the essential oils. Isolation and identification of the volatile compounds were performed using gas chromatography-mass spectrometry (GC-MS) instrument. The results of gas chromatography-flame ionization detector (GC-FID) analysis (quantification) showed that the main components in the essential oil of dill shoots were α-phellandrene, dill ether, and β-phellandrene, and the optimal harvest date was D2 (second harvest, fourth week of February 2015). For parsley shoots, the main compounds were 1,3,8-p-menthatriene, β-phellandrene, and P1 (first harvest, third week of November 2014) was the sample with the highest essential oil. For coriander, the main compounds were E-2-dodecenal, dodecanal, and octane and the highest contents were found at C2 (second harvest, 5 February 2015); while, the main two components of mint essential oil were carvone and limonene, and the highest contents were found at M1 (first harvest, second week of December 2014). The present study was the first one reporting data on descriptive sensory analysis of aromatic herbs at this optimal harvest date according to the content of volatile compounds of their essential oils.

Coal-Bed Methane Water Effects on Dill and Its Essential Oils.

Pumping water from coal seams decreases the pressure in the seam and in turn releases trapped methane; this is the most common and economic method of methane extraction. The water that is pumped out is known as "coal-bed methane water" (CBMW), which is high in sodium and other salts. In the past 25 yr, the United States has seen a 16-fold increase in the production of coal bed methane gas, and trillions of cubic meters are yet to be extracted. There is no sustainable disposal method for CBMW, and there are very few studies investigating the effects of this water on plants and their secondary metabolites and on soil properties. This study was conducted to determine the effects of CBMW on soil chemical properties and on the biomass and essential oil yield and composition of dill ( L.). This crop was grown in a greenhouse and was subjected to different levels of CBMW treatment: tap water only; 25% CBMW, 75% tap water; 50% CBMW, 50% tap water; 75% CBMW, 25% tap water; and 100% CBMW. The major dill oil constituents, limonene and α-phellandrene, were not affected by the treatments; however, the concentration of dill ether increased with increasing CBMW levels, whereas the concentration of carvone decreased. In soil, sodium level significantly increased with increasing level of treatment, but pH and cation exchange capacity were not much affected. Coal bed methane water could be used for irrigation of dill for one growing season, but longer-term studies may be needed to clarify the long-term effects on soil and plant.

Changes in Essential Oil Composition of Dill (Anethum graveolens L.) Grains in Response to Water Limitation and Nitrogen Fertilizer

In order to investigate the effects of irrigation and nitrogen fertilizer on essential oil composition of dill, this research was performed in 2010 at the Agricultural Research Farm of the University of Tabriz, Iran. The experiment was carried out as split plot on the basis of randomized complete block design with three replications. Irrigation treatments (irrigation after 70, 100 and 130 mm evaporation from class A pan) and nitrogen levels (0, 40, 80, 120 kgN/ha) were allocated to main and sub-plots, respectively. The essential oil from grains of dill was isolated by hydro distillation and analyzed by gas-chromatography (GC-MS). The main components of dill essential oil were found to be carvone (4.9 - 60.1 %), l-limonene (6.4 - 21.8 %), dillapiole (1.0-11.9 %), dihydrocarvone, apiole, l-phellandrene, hexacosane, octacosane, eicosane and anethole. The amount of cis-dihydrocarvone, trans- limonene oxide, limonene and dill ether were increased by water limitation. Nitrogen application increased carvone and dihydrocarvone in dill grains.