Influence of drying and extraction methods on yield and chemical composition of the essential oil of Satureja hortensis

The aerial parts of Satureja hortensis, cultivated in Iran (Research Station of Alborz, Karaj), were collected at the full-flowering stage and dried by three different drying methods (sun-drying, shade-drying and oven-drying at 45 °C). The essential oils of every treatment were obtained by hydro-distillation of the aerial parts. In addition, the essential oil of shade-dried sample was obtained by two other distillation methods (water- and steam-distillation and direct steam-distillation). The oils were analyzed by capillary GC and GC–MS. Statistical analysis showed no significant difference between oil yield (w/w) of the oven-dried sample (1.06%) compared to shade-dried (0.94%) and sun-dried (0.87%). The oil content of the shade-dried sample, obtained by hydro-distillation, was higher (0.94%) than that of the steam-distilled (0.27%). Twenty-three components were identified in the oil of S. hortensis in the different drying methods, including carvacrol (46.0–48.1%) and γ-terpinene (37.7–39.4%) as main components. Seventeen compounds were characterized in the oils of different distillation methods, including carvacrol (12.3–46%) and γ-terpinene (37.7–70.4%). Although the drying methods had no significant effect on oil composition of S. hortensis, the distillation changed the percentage of main components sharply (significant at 1%). The steam-distillation method produced the lowest amount of carvacrol and highest amount of γ-terpinene. The results showed that extraction by hydro-distillation gave the best results for S. hortensis, based on oil yield and carvacrol percentage.     

Phytochemical composition and antimicrobial activities of the essential oils from Satureja subspicata Vis. growing in Croatia

The present study describes the phytochemical profile and antimicrobial activity of Satureja subspicata Vis. essential oils, collected in Dalmatia (Croatia). Three samples of essential oils were obtained from the aerial parts of the plant by hydrodistillation and analyzed by GC–MS. From the 24 compounds representing 97.47% of the oils, carvacrol (16.76%), α-pinene (13.58), p-cymene (10.76%), γ-terpinene (9.54%) and thymol methyl ether (8.83%) appear as the main components. The oils also contained smaller percentages of myrcene, linalool, β-caryophyllene, limonene, geranyl acetate, 1-Octen-3-ol, nerol, thymol and borneol. Furthermore, antimicrobial activity of the oil was evaluated using agar diffusion and broth microdilution methods. The antimicrobial test results showed that the oils had a great potential antimicrobial activity against all 13 bacteria and 9 fungal strains. Gram-positive bacteria are more sensitive to the investigated oil, with a range of 0.09 to 6.25 μl/ml than Gram-negative bacteria in the range which is significantly higher from 1.56 to 25.00 μl/ml. Results presented here may suggest that the essential oil of S. subspicata possesses antimicrobial properties, and is therefore a potential source of antimicrobial ingredients for the food and pharmaceutical industry.     

The in vitro antioxidative properties of the essential oils and methanol extracts of Satureja spicigera (K. Koch.) Boiss. and Satureja cuneifolia ten

This study was designed to examine the in vitro antioxidant activities of the essential oil and methanol extracts of Satureja spicigera and S. cuneifolia from Turkish flora. GC and GC/MS analysis of the essential oils resulted in the identification of 40 and 29 compounds, representing the 99.4% and 99.5% of the oils, respectively. Major constituents of the oils were carvacrol (42.5% and 67.1%), γ-terpinene (21.5% and 15.2%) and p-cymene (20.9% and 6.7%), respectively. Methanol extracts were also obtained from the aerial parts of the plants. The samples were subjected to a screening for their possible antioxidant activities by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene–linoleic acid assays. In general, samples obtained from S. cuneifolia exerted greater antioxidant activities than did those obtained from S. spicigera. In the DPPH test system, free radical-scavenging activity of S. spicigera oil was determined to be 127 ± 1.63 μg/ml, whereas IC₅₀ value of S. cuneifolia was 89.1 ± 2.29 μg/ml. In the β-carotene–linoleic acid test system, antioxidant activities of the oil were 81.7 ± 1.14% and 93.7 ± 1.83%, respectively. Antioxidant activities of the synthetic antioxidant, BHT, ascorbic acid, curcumin and α-tocopherol were also determined in parallel experiments.     

Essential oil composition,antimicrobial and antioxidant activities of Satureja cuneifolia Ten.

Satureja cuneifolia Ten. is a well-known aromatic plant which is frequently used as a spice and herbal tea in Anatolia. S. cuneifolia oil was analyzed by gas chromatography/mass spectrometry (GC/MS). The major components of S. cuneifolia oil were carvacrol (44.99%) and p-cymene (21.61%). The essential oil of S. cuneifolia exhibited antimicrobial activity against all of the tested foodborne and spoilage bacteria. The minimum inhibitory concentration (MIC) values for test bacteria which were sensitive to the essential oil of S. cuneifolia were in the range of 600–1400 μg/ml. Antioxidant activities of the essential oil and the methanolic extract from S. cuneifolia were evaluated by using DPPH radical scavenging, β-carotene–linoleic acid bleaching and metal chelating activity assays. In addition, the amounts of total phenol components in the plant methanolic extract (222.5 ± 0.5 μg/mg) and the oil (185.5 ± 0.5 μg/mg) were determined.     

Satureja horvatii essential oil: In vitro antimicrobial and antiradical properties and in situ control of Listeria monocytogenes in pork meat

The dominant compounds in Satureja horvatii oil were p-cymene (33.14%), thymol (26.11%) and thymol methyl ether (15.08%). The minimum inhibitory concentration (MIC) varied from 0.03 to 0.57 mg/mL for bacteria, and from 0.56 to 2.23 mg/mL for yeast strains, while minimum bactericidal/yeast-cidal concentration (MBC/MYC) varied from 0.07 to 1.15 mg/mL and 1.11 to 5.57 mg/mL for bacteria and yeasts, respectively. The antiradical potential of the essential oil was evaluated using hydroxyl radical (•OH) generated in Fenton reaction. The meat preserving potential of essential oil from Satureja horvatii was investigated against L. monocytogenes. Essential oil successfully inhibited development of L. monocytogenes in pork meat. Sensorial evaluation on flavor and color of meat was performed. The color and flavor of meat treated with essential oil improved after 4 days of storage. S. horvatii essential oil can act as a potent inhibitor of food spoiling microorganisms, in meat products and also can be a useful source of natural antioxidants.     

Effects of drying methods on the quality and quantity of the essential oil of Mentha longifolia L. subsp. Capensis

The effects of various methods of drying on the content and chemical quality of the essential oil of Mentha longifolia was studied. The most prominent component in both the air-dried and sun-dried leaf oils was menthone (47.9% and 38.3%, respectively), while oven-dried leaf oil had limonene as the major compound (40.8%), whereas pulegone was the major compound from the original fresh leaf oil. Menthone and pulegone were not detected in the oven-dried leaf oil. The essential oil underwent significant chemical transformation in its monoterpenoids when the leaves were dried by the three different methods. Due to the significant reduction of the potentially harmful pulegone and menthone by oven-drying, it is suggested that this herb should be oven-dried or cooked before consumption in order to reduce toxicity.     

GC/MS analysis and in vitro antioxidant activity of essential oil and methanol extracts of Thymus caramanicus Jalas and its main constituent carvacrol

Chemical composition of the essential oil, antioxidant activity (DPPH and β-carotene/linoleic acid assays), and total phenolic content (Folin–Ciocalteu assay) of aerial parts of Thymus caramanicus were determined. The highest radical-scavenging activity (DPPH test) was shown by the polar subfraction of the methanol extract (IC₅₀ = 43.0 μg/ml) which was also higher than that of butylated hydroxytoluene (BHT, IC₅₀ = 19.7 μg/ml). However, it was the nonpolar subfraction of the methanol extract that showed the highest inhibition (84.4%), as assessed by the β-carotene/linoleic acid assay, which was only slightly lower than that shown by BHT (93.3%). The antioxidant activities of the essential oil main component (carvacrol) were also evaluated for comparison. Total phenolic content of the polar subfraction, as gallic acid equivalents, was 124.3 μg/mg. Essential oil extracted from the aerial parts by hydrodistillation was analysed by GC and GC/MS. Fifteen constituents, representing 99.3% of the oil, were identified, of which the major ones, carvacrol (85.9%), thymol (3.3%), p-cymene (3.2%), γ-terpinene (1.8%) and borneol (1.3%), accounted for 95.6% of the oil.     

Chemical composition,cytotoxic and antioxidant activity of the leaf essential oil of Photinia serrulata

The leaf essential oil of Photinia serrulata was obtained by hydrodistillation and analyzed by GC and GC-MS. Seventy-one components were identified in the essential oil and the main components of the oil were 10-epi-γ-eudesmol (12.72%), pinene (6.85%), sabinene (5.93%), α-humulene (5.87%) and α-thujene (5.47%). The in vitro cytotoxicity of the oil on human cancer cell lines Hela, A-549 and Bel-7402 was examined. The oil was found to be very active against all the three human tumor cell lines tested with low IC₅₀ of 0.0427 μl/ml (Hela), 0.0219 μl/ml (A-549) and 0.0301 μl/ml (Bel-7402). The oil was also found to possess antioxidant activity as demonstrated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method.     

Chemical and antimicrobial analyses of essential oil of Lippia origanoides H.B.K

Lippia origanoides H.B.K. (Verbenaceae) is a plant known in Oriximiná (Brazil) as “Salva-de-Marajó”. Its leaves are widely used as of a spice in cooking and in traditional medicine. The chemical composition of the essential oil obtained from its leaves, analyzed by GC and GC/MS, showed a high content of oxygenated monoterpenes (66.0%), carvacrol (38.6%) and thymol (18.5%) being the major constituents. Considering that previous studies on the same plant species showed carvacrol as a trace or absent compound, we propose the existence of a new chemotype for this species. A high carvacrol content in the essential oil determines the plant’s suitability for the preparation of oregano condiment. The antimicrobial activity of this essential oil was determined by the drop diffusion method, showing highly significant inhibition zones for all microorganisms tested.     

Study on chemical composition and biological activities of essential oil and extract from Salvia pisidica

In this study, total contents of phenolic, flavanol and flavonol, antioxidant activities and antimicrobial activities of the Turkish endemic Salvia pisidica Boiss. & Heldr. ex Bentham (Lamiaceae) extract and essential oil were assessed in vitro. Total phenolic, flavanol and flavonol contents in the extract were 54.57 mg gallic acid equivalents (GAE)/g, 16.70 mg catechine equivalents (CE)/g and 18.19 mg rutin equivalents (RE)/g, respectively. Antioxidant activities (IC₅₀ value) of the extract and essential oil were determined as 4.88 and 6.41 mg/mL by DPPH assay, respectively. 31 compounds were determined in the essential oil using GC-MS and the major compounds (%) were camphor (23.76), sabinol (19.2), α-thujone (14.2) and eucalyptol (1.8-cineole) (5.8).The antimicrobial activity of the methanolic extract and the essential oil against 13 bacterial and two yeast strains was determined. The extract (concentration 5 g/100 ml or 10 g/100 ml) was effective against most of the strains tested, yet not against Bacillus cereus, Staphylococcus aureus, Aeromonas hydrophila and the two yeast strains tested. The essential oil (2 g/100 ml) showed an antimicrobial effect against all the gram (+) bacteria tested, against Saccharomyces cerevisiae, but was not effective against all gram (−) bacteria and Candida albicans. These results show that S.piscidica essential oil and extract could be considered as a natural alternative to traditional food preservatives and be used to enhance food safety and shelf life.     

The essential oil of Glossogyne tenuifolia

Glossogyne tenuifolia (Labill) Cass. (Compositae) is a traditional anti-pyretic and hepatoprotective herb in The Pescadores Islands. The essential oil of the dried herb, from four seasons, was isolated using a simultaneous steam-distillation and solvent-extraction (SDE) apparatus. The essential oil contents were in the range of 0.48–0.77 mg g⁻¹, with an average of 0.66 mg g⁻¹, and declined with the seasons. Generally, the essential oils from four seasons exhibited similar volatile profiles. A total of 62 different compounds were isolated by the SDE method and, among them, 30 compounds were identified, including 13 terpenes, 16 oxygen-containing compounds (eight alcohols, five aldehydes, one ester and two ketones) and one other compound. Terpenes were predominantly present in the essential oil and accounted for 61.3–76.0% of the essential oil with an average of 69.1%. The second most abundant class was alcohols, accounting for 12.4–15.9% of the essential oil, with an average of 14.1%. Consistently for four seasons, the most abundant eight compounds were in the descending order: p-cymene > β-pinene > β-phellandrene > limonene > cryptone > α-pinene > 4-terpineol + γ-muurolene. However, these eight compounds accounted for 71.5% of the average of the essential oil and, in combination, might give rise to the overall citrus-like aroma of the G. tenuifolia.     

Fractionation of citronella (Cymbopogon winterianus) essential oil and concentrated orange oil phase by batch vacuum distillation

The aim of this work was to assess the performance of a vacuum fractionating column for the fractionation of citronella essential oil and concentrated orange oil phase during batch mode operation at different pressures, from 20 to 1 mbar and reflux ratios from 1:1 to 10:1. Fractions from column top and bottom were analyzed by gas chromatography (GC/FID) using authentic standards of major constituents of the oils. Good fractionation results for citronella essential oil were achieved, affording complete removal of limonene, with a rich citronellal fraction and an output stream constituted mainly by citronellol and geraniol. Likewise, the use of the vacuum fractionation column allowed almost complete removal of limonene (∼0.7 wt% at column bottom) from the orange oil phase at the lowest operating pressure, 1 mbar, while the higher valencene content (20.5 wt%) was obtained at 10 mbar and reflux ratio of 1:1.     

Chemical composition and antioxidant activity of the essential oil of Clinopodium vulgare L.

This study was designed to examine the chemical composition and in vitro antioxidant activity of the essential oil of Clinopodium vulgare. GC–MS analysis of the oil resulted in the identification of 40 compounds, representing 99.4% of the oil; thymol (38.9%), γ-terpinene (29.6%) and p-cymene (9.1%) were the main components. The samples were subjected to a screening for their possible antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene-linoleic acid assays. In the first case, IC₅₀ value of the C. vulgare essential oil was determined as 63.0 ± 2.71 μg/ml. IC₅₀ value of thymol and γ-terpinene, the major compounds of the oil, was determined as 161 ± 1.3 μg/ml and 122 ± 2.5 μg/ml, respectively, whereas p-cymene did not show antioxidant activity. In β-carotene-linoleic acid system, C. vulgare essential oil exhibited 52.3 ± 1.19% inhibition against linoleic acid oxidation. In both systems, antioxidant capacities of BHT, curcumine and ascorbic acid were also determined in parallel experiments.     

Interference of Origanum vulgare L. essential oil on the growth and some physiological characteristics of Staphylococcus aureus strains isolated from foods

The aim of this study was to investigate the chemical composition of Origanum vulgare L. essential oil, the inhibitory effect of the oil on the cell viability of Staphylococcus aureus strains isolated from foods, and the influence of sub-inhibitory concentrations of the oil on some physiological attributes of these strains. GC-MS analysis showed that carvacrol (57.71%) was the most prevalent compound in the oil, followed by p-cymene (10.91%), γ-terpinene (7.18%), terpinen-4-ol (6.68%) and thymol (3.83%). The results showed that O. vulgare essential oil at 0.03, 0.6 and 0.12 μL mL⁻¹ inhibited the cell viability of Staph. aureus. At 0.12 μL mL⁻¹ the oil caused cidal effect with decrease ≥3 log cycles of the initial inoculum after 15 min of exposure. Sub-inhibitory concentrations (0.03 and 0.015 μL mL⁻¹) of the oil suppressed some physiological attributes of the Staph. aureus strains such as coagulase, lipase and salt tolerance. The oil interfered on the microbial metabolic activity in a dose-dependent manner. O. vulgare essential oil could be a novel antimicrobial with capability to suppress some physiological characteristics, in addition to inhibit the growth and survival of pathogen bacteria in foods, particularly Staph. aureus.     

Composition of oregano essential oil (Origanum vulgare) as affected by drying method

The influence of the drying method on volatile compounds of Origanum vulgare was evaluated. The drying methods tested were convective (CD) at 60 °C and vacuum-microwave (VMD), as well as a combination of convective pre-drying and VM finish-drying (CPD–VMFD). The volatile compounds of fresh and dried oregano were extracted by steam-hydrodistillation and analyzed by GC–MS. Oregano drying kinetics was described by a simple exponential model for CD and CPD–VMFD, while VMD kinetics consisted of two periods: linear until a critical point and exponential beyond that point. Thirty-four compounds were tentatively identified, with carvacrol, thymol, and γ-terpinene, being the major components. The total volatiles concentration of fresh oregano (33.0 g kg⁻¹) decreased significantly during drying, independently of the method used (CD: 10.2 g kg⁻¹, CPD–VMFD: 13.1 g kg⁻¹, and VMD: 27.9 g kg⁻¹). The final conclusion was that VM dehydrated Polish oregano was of better aromatic quality than that dried using hot air.     

Chemical composition and antioxidant and antimicrobial activity of two Satureja essential oils

Hydro-distilled volatile oils from the aerial parts of Satureja montana L., and Satureja subspicata Bartl. ex Vis., growing wild in Bosnia and Herzegovina, were analyzed by GC/MS. More than one hundred compounds were identified in both plant oils, representing 92.4–98.1% of the total oil. The major constituents of essential oils obtained from the plant material of S. montana, collected from two different localities, were thymol (31.7%), and geraniol (22.3%), respectively. The most abundant compounds in essential oils of S. subspicata, collected at two different stages of development, were thymol (28.6%), and spathulenol (37.6%), respectively. The screening of antimicrobial activity of essential oil samples was individually evaluated against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis using a paper disc diffusion method. All tested microorganisms were inhibited by essential oil samples. Antioxidant activity was tested using the DPPH radical-scavenging method. All samples showed activity comparable to thymol, which was used as a positive probe.     

Chemical composition and antimicrobial activity of the essential oil of Coriandrum sativum

The essential oil from leaves of Coriandrum sativum L. (Apiaceae), obtained by hydro-distillation was analysed by gas chromatography–mass spectrometry (GC–MS) and also evaluated for in vitro antimicrobial activity. Out of 27 peaks, 24 components, which constitute 92.7%, were identified in the oil. The oil was dominated by aldehydes and alcohols which accounted for 56.1% and 46.3% of the oil, respectively. The major constituents were 2E-decenal (15.9%), decanal (14.3%), 2E-decen-1-ol (14.2%) and n-decanol (13.6%). Other constituents present in fairly good amounts are 2E-tridecen-1-al (6.75%), 2E-dodecenal (6.23%), dodecanal (4.36%), undecanol (3.37%), and undecanal (3.23%). The oil was screened for antimicrobial activity against both Gram positive (Staphylococcus aureus, Bacillus spp.) and Gram negative (Escherichia coli, Salmonella typhi, Klebsiella pneumonia, Proteus mirabilis, Pseudomonas aeruginosae) bacteria and a pathogenic fungus, Candida albicans. The oil showed pronounced antibacterial and antifungal activity against all of the microbes tested, except for P. aeruginosae, which showed resistance.     

Variations in essential oil and fatty acid composition during Myrtus communis var. italica fruit maturation

The essential oil and fatty acid composition of Myrtus communis var. italica fruit during its ripening was determined. The effect of the harvesting time on some physical properties of Myrtus fruits, fruit weight and moisture content, were significant. The increase of fruit weight (from 2.54 to 8.79 g% fruits) during ripeness was correlated positively with that of moisture content (from 28% to 72%). Fruit essential oil yields varied from 0.003% to 0.01% and showed a remarkable increase at 60 days after flowering to reach a maximum of 0.11%. Forty-seven volatile compounds were identified in fruit essential oils; 1,8-cineole (7.31–40.99%), geranyl acetate (1.83–20.54%), linalool (0.74–18.92%) and α-pinene (1.24–12.64%) were the main monoterpene compounds. Total fatty acid contents varied from 0.81% to 3.10% during fruit maturation and the predominant fatty acids were linoleic (12.21–71.34%), palmitic (13.58–37.07%) and oleic (6.49–21.89%) acids. The linoleic acid proportions correlated inversely with palmitic and oleic acids during all the stages of ripening.     

Extraction of Cuminum cyminum essential oil by combination technology of organic solvent with low boiling point and steam distillation

Extraction of essential oil from Cuminum cyminum seeds using a combination of organic solvent with low boiling point and steam distillation was explored. The effect of different parameters, such as particle size (40, 60, 80 mesh), temperature (°C) 10, 15, 20 and extraction time (3, 5, 8 h), on the extraction yield was investigated using three-level orthogonal array design. The experimental results showed that the temperature had the largest effect on the yield of the extract (oleoresin), followed by extraction time and particle size. The optimum parameters, such as temperature, particle size, and extraction time were in turn 20 °C, 80 mesh, and 8 h. Essential oil of C. cyminum seeds obtained by supercritical fluid extraction (SFE), hydrodistillation (HD), combination technology of organic solvent with low boiling point and steam distillation (OS-SD) were further analysed by gas chromatographic/mass spectrometric detection to compare the extraction methods. Forty-five compounds in the C. cyminum essential oil were identified, showing that the composition of the extraction by different methods was mostly similar, whereas relative concentration of the identified compounds was apparently different. General characteristics of the C. cyminum essential oil obtained by different methods were further compared, and OS-SD was considered as the optimum process among the three processes to obtain C. cyminum essential oil for high quality, simple technology and low cost.     

Composition,cytotoxicity and antimicrobial activity of essential oil from Dictamnus dasycarpus

The composition of the essential oil from Dictamnus dasycarpus was analysed by GC–MS; 47 constituents (88.9% of the total oil) were identified. The main compounds were syn-7-hydroxy-7-anisylnorbornene (29.4%), pregeijerene (15.5%) and geijerene (11.4%). The antimicrobial activity of the essential oil was evaluated against nine microorganisms using disc diffusion and broth microdilution methods. The oil showed the strongest bactericidal activity against Staphylococcus aureus ATCC 25923 and methicillin-resistant S. aureus. The in vitro cytotoxicity of the oil on six human cancer cell lines was also examined. The cytotoxicity of the oil on three human breast cancer cell lines was significantly stronger than on other cell lines.