Supercritical carbon dioxide extraction and fractionation of fennel oil

Ground fennel seeds were extracted with supercritical carbon dioxide. Small-scale subsequent extractions of the same sample showed that the composition of volatile compounds was changed with the extension of extraction time and only principal volatile components (limonene, fenchone, methylchavicol, and anethole) were present in the last-extracted sample. Fennel oil was successfully fractionated into the essential oil rich and fatty oil rich products in pilot-scale apparatus using two separators in series. Designed experiments were carried out to map the effects of pressure and temperature in the first separator on the yields and compositions of the products. The minimum level of the total undesired components in both essential oil rich and fatty oil rich products appeared at a pressure of 80-84 bar and a temperature of 31-35 degrees C in the first separator. Supercritical CO(2) extraction of fennel seeds resulted in higher yield (10.0%) than steam distillation (3.0%), almost the same yield as hexane extraction (10.6%), and lower yield than alcohol extraction (15.4%). Analysis of the volatile compounds revealed the significant difference of the composition in distilled oil and oleoresins prepared by CO(2) and solvent extractions. Sensory evaluation showed that the CO(2) extraction product and distilled oil were more intense in odor and taste than alcohol and hexane extracts.     

Supercritical carbon dioxide extraction and characterization of Laurus nobilis essential oil

Supercritical carbon dioxide extraction allowed essential oil of Laurus nobilis to be obtained. Extraction conditions were as follows: pressure, 90 bar; temperature, 50 degrees C; and carbon dioxide flow, Phi = 1.0 kg/h. Waxes were entrapped in the first separator set at 90 bar and -10 degrees C. The oil was recovered in the second separator working at 15 bar and 10 degrees C. The main components were 1,8-cineole (22.8%), linalool (12.5%), alpha-terpinyl acetate (11.4%), and methyleugenol (8.1%). Comparison with the hydrodistilled oil did not reveal any significant difference. Collection of samples at different extraction times during supercritical extraction allowed the change of the oil composition to be monitored. Lighter compounds such as hydrocarbon and oxygenated monoterpenes were extracted in shorter times than the heavier hydrocarbon and oxygenated sesquiterpenes.     

Comparison of eucalyptus camaldulensis Dehn. oils from Mozambique as obtained by hydrodistillation and supercritical carbon dioxide extraction

Leaf oils of E. camaldulensis Dehn. from Mozambique obtained by hydrodistillation and by supercritical carbon dioxide extraction under different conditions were compared with regard to their major components. The oil obtained by hydrodistillation showed high concentrations of 1,8-cineole (43%), alpha-pinene (5.5%), beta-pinene (3.4%), p-cymene (5.2%), terpinen-4-ol (3.1%), and globulol (4.1%). The extracts obtained by supercritical carbon dioxide extraction have lower amounts of 1,8-cineole, alpha-pinene, beta-pinene, and terpinen-4-ol, but have higher amounts of allo-aromadendrene and globulol. At the same time, distilled oil of E. radiata was extracted from an inert matrix (Celite) and the extract showed a higher content of 1,8-cineole at 80 bar and 60 degrees C than the feed, suggesting that a multiple-stage supercritical carbon dioxide extraction of the E. camaldulensis studied can produce an oil close to the market requirements set by the European pharmacopoeias.     

Supercritical carbon dioxide extraction of essential oils from Perovskia atriplicifolia Benth

The supercritical fluid extraction (SFE) of the aerial parts of Perovskia atriplicifolia Benth. was studied. The effect of different parameters such as pressure, temperature, modifier identity, and modifier volume on the SFE of the plant was investigated. The extracts were analyzed by GC and GC-MS and compared with the essential oil obtained from P. atriplicifolia Benth by steam distillation. The supercritical extracts and the steam-distilled products had very different compositions. The main constituents of the oil obtained by steam distillation were 1,8-cineole, limonene, camphor, beta-caryophyllene, alpha-pinene, camphene, and alpha-humulene. On the other hand, the major components of SFE extracts were 1,8-cineole, limonene, camphor, beta-caryophyllene, gamma-cadinene, alpha-pinene, and alpha-terpinyl acetate. The results showed that increasing the temperature from 35 to 65 degrees C (at a constant pressure of 100 atm) drastically reduced the number of extracted components. Also, the number of extracted constituents and the percent of main analytes increased when lower pressures were used. Using different modifiers (e.g., methanol, ethanol, dichloromethane, and hexane) for the extraction of the plant at low pressure (100 atm) and temperature (35 degrees C) showed that hexane was more selective than the other modifiers.     

Chemical composition of the essential oil and supercritical CO2 extract of Commiphora myrrha (Nees) Engl. and of Acorus calamus L

Volatile concentrates from the oleo-gum resin of Commiphora myrrha (Nees) Engl. and from the rhizomes of Acorus calamus were isolated by supercritical extraction with carbon dioxide. The volatile oil of myrrh was obtained at 9.0 MPa and 50 degrees C and at a CO2 flow of 1.5 kg/h. Acorus calamus was extracted at 9.0 MPa and 45 degrees C and at a CO2 flow of 1.6 kg/h. In both cases, an oil devoid of cuticular waxes was obtained with a single depressurization stage. The SFE myrrh oil had a yield, Y, of 3.2%. Its main components, identified and quantified by GC/MS, were furanoeudesma-1,3-diene, 34.9%; lindestrene, 12.9%; curzerene, 8.5%; and germacrone, 5.8%. The essential oils from the same starting material by hydrodistillation, HD, (Y = 2.8%) and by steam distillation, SD, (Y = 0.4%) were quite similar to the SFE extract. The main components of the SFE oil of A. calamus (Y = 3.5%) were acorenone, 13.4%; iso-acorone, 11.6%; (Z)-sesquilavandulol, 11.0%; dehydroxy isocalamendiol, 7.7%; and beta-asarone, 5.5%. The comparison with hydrodistilled (Y = 1.8%) and steam distilled (Y = 1.0%) oils revealed large differences in the content of iso-acorone and crypto-acorone.     

Essential oils from Mediterranean lamiaceae as weed germination inhibitors

The essential oils obtained from rosemary (Rosmarinus officinalis L.), thyme (Thymus vulgaris L.), and savory (Satureja montana L.) and the four monoterpenes that are their major constituents have been analyzed by GC and GC-MS and tested for their allelopathic properties on the seeds of three different annual weeds (Chenopodium album, Portulaca oleracea, and Echinochloa crus-galli) and three crops (Raphanus sativus, Capsicum annuum, and Lactuca sativa), with the aim to evaluate in vitro their potential as germination inhibitors. The essential oil composition varied with the species, thymol being the main constituent (44%) of thyme and carvacrol (57%) that of savory oil. Differences in essential oil composition were observed within two different rosemary ecotypes, type A, with alpha-pinene (37%) and 1,8-cineole (23%), and type B, characterized by a 2-fold content of 1,8-cineole (47%). This latest essential oil inhibited completely the germination of weeds while concurrently displaying little effect on pepper. The other two oils showed less selective action. S. montana essential oil, with 57% carvacrol, is the most active compound, completely inhibiting germination both of crops and weeds. Borneol, one of the main constituents of the oil of rosemary type B, showed an activity comparable to that of the whole oil. Crop and weed seeds treated with 1,8-cineole showed germination values that were not significantly different from controls, even if a slowing of the germination process expressed in terms of a significant increase in mean germination time was observed. Monoterpene compounds also present in the essential oils mainly represented the volatile fraction released from the crops and their residues into the soil.     

Evolution and occurrence of 1,8-cineole (eucalyptol) in Australian wine

A new method has been developed for the quantitation of 1,8-cineole in red and white wines using headspace solid-phase microextraction (SPME) combined with stable isotope dilution analysis (SIDA) and gas chromatography-mass spectrometry (GC-MS). An extensive survey of Australian wines (44 white and 146 red) highlighted that only red wines contained significant amounts of 1,8-cineole (up to 20 μg/L). Hydrolytic studies with limonene and α-terpineol, putative precursors to 1,8-cineole, showed a very low conversion into 1,8-cineole (< 0.6%) over a 2 year period, which does not account for the difference between white and red wines. 1,8-Cineole was chemically stable in model wine solution over 2 years, and absorption from a Shiraz wine by bottle closures was most evident for a synthetic closure only (14% absorption after 1 year). Two commercial ferments at two different locations were monitored daily to investigate the evolution of 1,8-cineole throughout fermentation. Both ferments showed daily increases in 1,8-cineole concentration while in contact with grape solids, but this accumulation ceased immediately after pressing. This observation is consistent with the extraction of 1,8-cineole into the ferment from the solid portions of the grape berries.     

Acaricidal activity of pine essential oils and their main components against Tyrophagus putrescentiae,a stored food mite

Some essential oils obtained from the branches of four Pinus species (P. pinea L., P. halepensis Mill., P. pinaster Soil in Ait., and P. nigra Arnold) have been evaluated for their acaricidal activity by aerial diffusion against the stored food mite Tyrophagus putrescentiae (L.). All the essential oils showed a good efficacy, but P. pinea oil and its two constituents 1,8-cineole and limonene were the most effective compounds, showing 100% acaricidal activity at 8 microL; 1,8-cineole showed the same activity at 6 microL.     

Chemical composition of volatiles in Sardinian myrtle (Myrtus communis L.) alcoholic extracts and essential oils

The chemical composition of the volatile fraction of myrtle (Myrtus communis L.) alcoholic extracts and essential oils from leaves and berries collected in different places in Sardinia (Italy) was studied. A simple and rapid liquid-liquid extraction method was used to isolate volatile compounds from myrtle alcoholic extracts followed by GC and GC-MS analysis allowing the detection of 24 compounds. The volatile fraction was characterized by the terpenes fraction corresponding to that of the essential oils and by a fatty acid ethyl esters fraction. The variation during extraction of the volatile fraction in alcoholic extracts of berries and leaves was evaluated. Essential oils were obtained by hydrodistillation, and the yields were on average 0.52 +/- 0.03% (v/w dried weight) and 0.02 +/- 0.00% for leaves and berries, respectively. The essential oils were analyzed by GC and GC-MS, and a total of 27 components were detected, accounting for 90.6-98.7% of the total essential oil composition. Strong chemical variability depending on the origin of the samples was observed. The major compounds in the essential oils were alpha-pinene (30.0 and 28.5%), 1,8-cineole (28.8 and 15.3%), and limonene (17.5 and 24.1%) in leaves and berries, respectively, and were characterized by the lack of myrtenyl acetate.     

Influence of drying on the flavor quality of spearmint (Mentha spicata L.)

Spearmint (Mentha spicata L.) was dried using three different drying methods: oven-drying at 45 degrees C, air-drying at ambient temperature, and freeze-drying. The effect of the drying method on the volatile compounds and on the structural integrity and sensory characteristics of the spice was evaluated. The volatile components from fresh and dried spearmint samples were isolated by simultaneous distillation-extraction (SDE) and analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 28 compounds were identified, carvone, limonene, and 1,8-cineole, in that order, being the main components in all of the samples. Oven-drying at 45 degrees C and air-drying at ambient temperature were the methods that produced the best results. An increase in monoterpenes was observed in all of the dried samples, except in the freeze-dried samples that underwent freezing at -198 degrees C. Freeze-drying resulted in substantial losses in oxygenated terpenes and sesquiterpenes. The effect of each drying method on leaf structure was observed by scanning electron microscopy. From a sensory standpoint, drying the spearmint brought about a decrease in herbaceous and floral notes together with an increase in minty odor.     

Quality Comparison of Rice Bran Oil Extracted with d‐Limonene and Hexane

d‐Limonene, a safe agricultural by‐product, was used to extract rice bran oil and compared against hexane, a petroleum product widely used as a solvent for extracting edible oil. The yield of crude rice bran oils extracted with both solvents in percentage by weight was obtained. The quality of crude rice bran oil was analyzed. The yield and quality of crude rice bran oil from the limonene‐based solvent extraction were almost equivalent to those from the hexane‐based operation. The optimum solvent‐to‐rice bran ratio and extraction time required for d‐limonene extraction of oil, based primarily on crude rice bran oil yield, have been determined to be 5:1 and 0.5 hr, respectively. Despite the absence of antioxidants during the limonene recovery step with vacuum evaporation, the quantity of the oxidation products in the recovered limonene was <1% (wt) of the original limonene solvent. The application of d‐limonene solvent as an alternative to hexane in edible oil extraction could potentially eliminate the safety, environmental, and health issues associated with the use of hexane.     

Main agronomic-productive characteristics of two ecotypes of Rosmarinus officinalis L. and chemical composition of their essential oils

The productive potential of two different ecotypes of Rosmarinus officinalis (Cevoli and Lunigiana) cultivated in the littoral area near Pisa (northern Tuscany, Italy) and the differences in the yield and composition of the essential oils of leaves, flowers, and stems obtained from different positions of the plants were used to characterize the two ecotypes. The Cevoli ecotype plant produced the highest yield of dry matter (221 g plant-1) in comparison to the Lunigiana ecotype (72 g plant-1). There were significant differences in dry matter production of different organs of both ecotypes. The essential oil contents of Cevoli and Lunigiana ecotypes were similar. In contrast, the oil contents of the different plant parts showed marked differences. The apical part of the plant and the leaves gave the highest essential oil yields. The major difference between the oils of the two ecotypes consisted in the 1,8-cineole contents (6.6 and 37.9% in Cevoli and Lunigiana, respectively). The Cevoli ecotype was determined to be the most suitable for essential oil extraction because it was characterized by a preponderance of flowers and leaves in the apical portion. The Cevoli ecotype could be classifited as an alpha-pinene chemotype, whereas Lunigiana is a 1,8-cineole chemotype.     

Inhibitory effect of monogalactosyldiacylglycerol, extracted from spinach using supercritical CO2, on mammalian DNA polymerase activity

We investigated the effective extraction of monogalactosyldiacylglycerol (MGDG) from dried spinach (Spinacia oleracea) using supercritical fluid carbon dioxide (SC-CO(2)) with a modifier/entrainer. The yield of MGDG in the SC-CO(2) extract was not influenced by increasing temperature at a constant pressure, although the total extract yield was decreased. The total extract yield and MGDG yield in the extract from commercially purchased spinach (unknown subspecies), were greatly influenced by lower pressure. In a modifier (i.e., ethanol) concentration range of 2.5-20%, both the extract and MGDG yield increased as the ethanol concentration rose. The highest total extract yield (69.5 mg/g of spinach) and a good MGDG yield (16.3 mg/g of spinach) were obtained at 80 degrees C, 25 MPa, and 20% ethanol. The highest MGDG concentration (76.0% in the extract) was obtained at 80 degrees C, 25 MPa, and 2.5% ethanol, although the total extract yield under these conditions was low (5.2 mg/g of spinach). The optimal conditions for the extraction of MGDG were 80 degrees C, 20 MPa, and 10% ethanol. Of the 11 subspecies of spinach tested under these conditions, "Ujyou" had the highest concentration of MGDG. The total extract yield and MGDG concentration of Ujyou were 20.4 mg of the extract/g of spinach and 70.5%, respectively. The concentration of MGDG was higher in the SC-CO(2) extract than in the extract obtained using solvents such as methanol and n-hexane. The extract of Ujyou, which was the optimal subspecies for the extraction of MGDG, inhibited the activity of calf DNA polymerase alpha with IC(50) values of 145 microg/mL but was not effective against DNA polymerase beta.     

Volatile metabolites from Salvia fruticosa as antifungal agents in soilborne pathogens

The volatile metabolites of Salvia fruticosa plants, growing wild in 15 localities scattered across Greece, were analyzed by means of GC and GC-MS. The essential oil content ranged from 0.69 to 4.68%, and the results of the analyses showed a noticeable variation in the amounts of the five main components [1,8-cineole, alpha-thujone, beta-thujone, camphor, and (E)-caryophyllene]. The antifungal activities of the essential oils from two localities, belonging in two different groups of cluster and principal component analysis, and their main components (1,8-cineole and camphor) were evaluated in vitro against five phytopathogenic fungi. Both oils were slightly effective against Fusarium oxysporum f. sp. dianthi and Fusarium proliferatum, whereas against Rhizoctonia solani, Sclerotinia sclerotiorum, and Fusarium solani f. sp. cucurbitae the oils exhibited high antifungal activities.     

Antioxidant activity of extracts of black sesame seed (Sesamum indicum L.) by supercritical carbon dioxide extraction

Antioxidant activities of extracts derived from sesame seed by supercritical carbon dioxide (SC-CO(2)) extraction and by n-hexane were determined using alpha,alpha-diphenyl-beta-picylhydrazyl (DPPH) radical scavenging and linoleic acid system methods. The highest extracted yield was given at 35 degrees C, 40 MPa, and a CO(2) flow rate of 2.5 mL min(-1) by an orthogonal experiment. The yields of extracts increased with increasing pressure, and yields at 40 and 30 MPa were higher than that by solvent extraction at 46.50%. Results from the linoleic acid system showed that the antioxidant activity follows the order: extract at 35 degrees C, 20 MPa > BHT > extract at 55 degrees C, 40 MPa > extract at 55 degrees C, 30 MPa > Trolox > solvent extraction > alpha-tocopherol. The SC-CO(2) extracts exhibited significantly higher antioxidant activities comparable to that by n-hexane extraction. The extracts at 30 MPa presented the highest antioxidant activities assessed in the DPPH method. At 20 MPa, the EC(50) increased with temperature, which indicated that the antioxidant activity was decreased in a temperature-dependent manner. The significant differences of antioxidant activities were found between the extracts by SC-CO(2) extraction and n-hexane. However, no significant differences were exhibited among the extracts by SC-CO(2) extraction. The vitamin E concentrations were also significantly higher in SC-CO(2) extracts than in n-hexane extracts, and its concentrations in extracts corresponded with the antioxidant activity of extracts.     

Near infrared spectroscopy for cost effective screening of foliar oil characteristics in a Melaleuca cajuputi breeding population

The identification of Melaleuca cajuputi leaf samples (trees) that demonstrate enhanced oil characteristics using near infrared (NIR) spectroscopy is described. Leaf samples from an unthinned M. cajuputi seedling seed orchard in Indonesia were collected and air-dried, and their 1,8-cineole content and oil concentrations were determined. NIR spectra of the leaves were obtained, and calibrations for 1,8-cineole content and oil concentration were developed using spectra that had been selected using spectral features; that is, no knowledge of 1,8-cineole content or oil concentration was used to select the calibration samples. The calibrations were used to predict the 1,8-cineole content and oil concentration of the remaining samples. It was demonstrated that NIR spectroscopy could be used to identify leaf samples that had high 1,8-cineole contents and oil concentrations. The technique has the potential to greatly reduce the time involved in ranking large numbers of samples for these attributes, as is a requirement in tree breeding programs to enhance oil production.     

Optimization of a supercritical fluid extraction/reaction methodology for the analysis of castor oil using experimental design

The aim of this work was to optimize a supercritical fluid extraction (SFE)/enzymatic reaction process for the determination of the fatty acid composition of castor seeds. A lipase from Candida antarctica (Novozyme 435) was used to catalyze the methanolysis reaction in supercritical carbon dioxide (SC-CO(2)). A Box-Behnken statistical design was used to evaluate effects of various values of pressure (200-400 bar), temperature (40-80 degrees C), methanol concentration (1-5 vol %), and water concentration (0.02-0.18 vol %) on the yield of methylated castor oil. Response surfaces were plotted, and these together with results from some additional experiments produced optimal extraction/reaction conditions for SC-CO(2) at 300 bar and 80 degrees C, with 7 vol % methanol and 0.02 vol % water. These conditions were used for the determination of the castor oil content expressed as fatty acid methyl esters (FAMEs) in castor seeds. The results obtained were similar to those obtained using conventional methodology based on solvent extraction followed by chemical transmethylation. It was concluded that the methodology developed could be used for the determination of castor oil content as well as composition of individual FAMEs in castor seeds.     

Composition and Antimicrobial Activity of Anemopsis californica leaf oil

Isolation and characterization of leaf volatiles in Anemopsis californica (Nutt.) Hook. and Arn. (A. californica) was performed using steam distillation, solid-phase microextraction, and supercritical fluid extraction. Thirty-eight compounds were detected and identified by gas chromatography; elemicin was the major component of the leaf volatiles. While the composition of the leaf volatiles varied with method of extraction, alpha-pinene, sabinene, beta-phellandrene, 1,8-cineole, piperitone, methyl eugenol, (E)-caryophyllene, and elemicin were usually present in readily detectable amounts. Greenhouse-reared clones of a wild population of A. californica had an identical leaf volatile composition with the parent plants. Steam-distilled oil had antimicrobial properties against 3 (Staphylococcus aureus, Streptococcus pneumoniae, and Geotrichim candidum) of 11 microbial species tested. Some of this bioactivity could be accounted for by the alpha-pinene in the oil.     

Insecticidal effect and chemical composition of the volatile oil from Bergenia ligulata

The chemical composition of the volatile oil from roots of Bergenia ligulalta was analyzed by GC-MS. A total of 97 compounds were identified. (+)-(6S)-Parasorbic acid (1) (47.45%), isovaleric acid (6.25%), 1,8-cineole (4.24%), (Z)-asarone (3.50%), and terpinen-4-ol (2.96%) were the most prominent constituents. (+)-(6S)-Parasorbic acid (1) was isolated and characterized by spectroscopic data. This is the first report of the existence of (+)-(6S)-parasorbic acid in the saxifrage family. The volatile oil and the isolated compound were tested against Drosophila melanogaster . The results obtained showed that the volatile oil from roots could be considered as natural insecticidal effect agents.     

Volatile chemicals identified in extracts from leaves of Japanese mugwort (Artemisia princeps pamp.)

Extracts from leaves of Japanese mugwort (Artemisia princeps Pamp.) were obtained using two methods: steam distillation under reduced pressure followed by dichloromethane extraction (DRP) and simultaneous purging and extraction (SPSE). A total of 192 volatile chemicals were identified in the extracts obtained by both methods using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). They included 47 monoterpenoids (oxygenated monoterpenes), 26 aromatic compounds, 19 aliphatic esters, 18 aliphatic alcohols, 17 monoterpenes (hydrocarbon monoterpenes), 17 sesquiterpenes (hydrocarbon sesquiterpenes), 13 sesquiterpenoids (oxygenated sesquiterpenes), 12 aliphatic aldehydes, 8 aliphatic hydrocarbons, 7 aliphatic ketones, and 9 miscellaneous compounds. The major volatile constituents of the extract by DRP were borneol (10.27 ppm), alpha-thujone (3.49 ppm), artemisia alcohol (2.17 ppm), verbenone (1.85 ppm), yomogi alcohol (1.50 ppm), and germacren-4-ol (1.43 ppm). The major volatile constituents of the extract by SPSE were 1,8-cineole (8.12 ppm), artemisia acetate (4.22 ppm), alpha-thujone (3.20 ppm), beta-caryophyllene (2.39 ppm), bornyl acetate (2.05 ppm), borneol (1.80 ppm), and trans-beta-farnesene (1. 78 ppm).