Composition and biological activities of essential oils from four Heracleum species

The composition of essential oils from aerial parts of Heracleum persicum, a widely used medicinal plant, and three other Heracleum species growing wild in Iran were analysed by GC and GC–MS. Myristicin (53.6%), (E)-anethole (25.0%), hexyl butanoate (29.7%) and elemicin (41.1%) were the major compounds of Heracleum pastinacifolium, H. persicum, Heracleum rechingeri and Heracleum transcaucasicum, respectively. Cytotoxic activity assessed on three human cancer cell lines (HeLa, LS180 and Raji), showed that essential oils from H. transcaucasicum (IC₅₀ values; 0.362–0.594 mg/ml) followed by H. pastinacifolium (0.497–1.398 mg/ml) had moderate antitumoral activities. In the DPPH radical scavenging assay, H. pastinacifolium and H. persicum oils showed the highest activities with IC₅₀ values of 7.3 and 7.4 mg/ml, respectively. Antioxidant activity correlated well with the total phenolic content of the oils. None of the essential oils showed significant antimicrobial activities.     

Chemical and biological characteristics of Cuminum cyminum and Rosmarinus officinalis essential oils

Essential oils extracted by hydrodistillation from Cuminum cyminum and Rosmarinus officinalis were characterized by means of GC and GC–MS. C. cyminum and R. officinalis contained α-pinene (29.1%, 14.9%), 1,8-cineole (17.9%, 7.43%) and linalool (10.4%, 14.9%), respectively, as the major compounds. C. cyminum oil exhibited stronger antimicrobial activity than did R. officinalis oil against E. coli, S. aureus and L. monocytogenes. Complete death time on exposure to Cuminum cyminum L. and Rosmarinus officinalis L. oils were 20 and 25 min 180 and 240 min and 90 and 120 min for E. coli, S. aureus and L. monocytogenes, respectively. Radical-scavenging and antioxidant properties were tested by means of 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and the β-carotene bleaching test. These properties were compared to those of Thymus x-porlock essential oil, used as a reference ingredient. The radical scavenging performance of the rosemary oil was better than that of C. cyminum. Results from the antioxidant test were better than those provided by the radical-scavenging activity. C. cyminum and R. officinalis essential oils may be considered as potent agents in food preservation.     

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.     

Chemical composition and antimicrobial properties of essential oils of three Australian Eucalyptus species

The chemical composition and antimicrobial properties of the essential oils of three common Australian Eucalyptus species, namely E. olida, E. staigeriana and E. dives were determined by gas chromatography/mass spectrometry and the agar disc diffusion method, respectively. A total of 24 compounds were identified from the essential oil of E. dives, with the dominant compounds being piperitone (40.5%), α-phellandrene (17.4%), p-cymene (8.5%) and terpin-4-ol (4.7%). For E. staigeriana, 29 compounds were identified with 1,8-cineole (34.8%), neral (10.8%), geranial (10.8%), α-phellandrene (8.8%) and methyl geranate (5.2%) being the dominant ones. In contrast, a single compound, (E)-methyl cinnamate, accounted for 99.4% of the essential oils of E. oilda, although 20 compounds were identified. The essential oils displayed a variable degree of antimicrobial activity with E. staigeriana oil showing the highest activity. In general, Gram-positive bacteria were found to be more sensitive to the essential oils than Gram-negative bacteria. Staphylococcus aureus was the most sensitive strain while Pseudomonas aeruginosa was the most resistant.     

Phytochemical composition and in vitro antimicrobial and antioxidant activities of essential oils of three endemic Soqotraen Boswellia species

The chemical composition of three essential oils obtained from the barks of three endemic Boswellia species namely, Boswellia dioscorides, Boswellia elongata and Boswellia socotrana which were collected from the Soqotra Island (Yemen), was investigated. In parallel to that evaluation of their antimicrobial and antioxidant activities was also carried out. The investigation led to the identification of 72, 70 and 67 constituents for B.dioscorides, B. elongata, and B. socotrana, respectively. The B. dioscorides oil was found to have a high content of monoterpene hydrocarbons (32.8%) with α-thujene (9.3%) and α-pinene (8.3%) as main components. Whereas, the essential oil of B. elongata was characterised by high diterpene content (31.7%), in which incensol (14.8%) was found to be the major constituent. On the other hand, the oil obtained from the B. socotrana was found to be predominated of monoterpene hydrocarbons (26.4%) and oxygenated monoterpenes (30.7%) with p-cymene (13.0%), 2-hydroxy-5-methoxy-acetophenone (16.3%) and camphor (11.6%). All essential oils possessed antimicrobial activity especially against Gram-positive bacteria with MIC-values between 1.8 and 17.2 mg/ml. Furthermore, the DPPH-radical scavenging assay exhibited only weak antioxidant activities (28%) at 1.0 mg/ml.     

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.     

Essential oils of Lavandula bipinnata and their antimicrobial activities

The essential oils from dried leaves of Lavandula bipinnata (Roth) Kuntze (Lamiaceae), obtained by soxhlet extraction was analysed by gas chromatography–mass spectrometry (GC–MS) and was evaluated for in vitro antimicrobial activity. The most common components usually found in lavender essential oils were present in the oil samples analysed, out of 43 peaks, 29 components, which constitute 72.38%, were identified in the essential oil. The major constituents were transcarveol (18.93%), pulegone (8.45%), camphor (7.09%) and menthol (5.89%). Other constituents present in fairly good amounts are pipertone (4.65%), caryophyllene oxide (3.68%), linalyl acetate (3.37%) and bicyclogermacrene (3.09%). The essential oil was screened for antimicrobial activity by disc diffusion assay and minimum inhibitory concentration (MIC) against bacteria and fungus. Results reveal that L. bipinnata essential oils are inhibitory against the tested bacteria and fungal strains.     

Chemical composition,antimicrobial, cytotoxic and antioxidant activities of the essential oil of Artemisia indica Willd

Essential oil from the aerial parts of Artemisia indica was analysed by GC-FID and GC–MS. A total of 43 compounds representing 96.8% of the oil were identified and the major components were found to be artemisia ketone (42.1%), germacrene B (8.6%), borneol (6.1%) and cis-chrysanthenyl acetate (4.8%). Antimicrobial activity of the oil was evaluated against seven clinically significant bacterial and two fungal strains. The essential oil and its major constituents exhibited moderate to potent, broad-spectrum antibacterial and antifungal activities targeting both Gram-positive and Gram-negative bacteria. In vitro cytotoxicity evaluation against four human cancer cell lines THP-1 (leukemia), A-549 (lung), HEP-2 (liver) and Caco-2 (colon) showed that the essential oil exhibited concentration dependant growth inhibition in the 10–100 μg/ml dilution range, with IC₅₀ values of 10 μg/ml (THP-1), 25 μg/ml (A-549), 15.5 μg/ml (HEP-2) and 19.5 μg/ml (Caco-2). It was interesting to note that the essential oil also exhibited potent antioxidant activity.     

Chemical composition and some biological activities of the volatile oils of a chemotype of Lippia chevalieri Moldenke

The volatile oils of a chemotype Lippia chevalieri collected in Burkina-Faso were obtained by hydrodistillation and analysed by GC and GC/MS. Most of the constituents identified in leaves and flowers oils were sesquiterpenoids. The dominant components in the oil from leaves were β-caryophyllene (27%), elemol (22%) and caryophyllene oxide (9%) whereas those found in the oil from flowers were β-caryophyllene (30%), germacrene d (15%) and elemol (12%). The latter compound and 1,8-cineole may be considered as metabolic markers of flowers differentiation taking into account the local environmental changes. The antibacterial and antifungal activities of both oils were tested against six microorganisms. While a strong inhibitory effect was shown regarding the growth of Staphylococcus aureus and Enterococcus hirae, a moderated effect was observed for Candida albicans and Saccharomyces cerevisiae. Elemol, 1,8-cineole, camphor and para-cymene can be considered as the principal antimicrobial components of these oils. No antioxidant capacity comparable to that of α-tocopherol was demonstrated from either oil.     

Essential oils of Alpinia conchigera Griff. and their antimicrobial activities

The essential oils from the dried leaves, pseudostems and rhizomes of Alpinia conchigera Griff. (KL 5049), collected from Jeli province of Kelantan, east coast of Peninsular Malaysia, were isolated by hydrodistillation. The collected oils were analyzed by capillary GC and GC–MS. Forty one compounds were identified, among which 13 have not been detected previously. The leaf, pseudostem and rhizome oils afforded 40, 33 and 39 constituents, respectively. The most abundant components in the leaf oil included β-bisabolene (15.3%), β-pinene (8.2%), β-sesquiphellandrene (7.6%), chavicol (7.5%) and β-elemene (6.0%), while β-bisabolene (19.9%), β-sesquiphellandrene (11.3%), β-caryophyllene (8.8%) and β-elemene (4.7%) were the main components in the pseudostem. In the rhizome, 1,8-cineole (17.9%), β-bisabolene (13.9%), β-sesquiphellandrene (6.8%) and β-elemene (4.0%) were the major components. The essential oils were also subjected to antifungal and antibacterial tests, using the minimum inhibitory concentration (MIC) method. Results revealed weak inhibitions against the microorganisms tested.     

Phytochemical composition,anti-inflammatory and antitumour activities of four Teucrium essential oils from Greece

The essential oils of four Teucrium species were studied and 150 components, in all, were identified. All oils were rich in sesquiterpenes (50.1–55.8%). Spathulenol and δ-cadinene were the main compounds of Teucrium brevifolium oil; caryophyllene and 4-vinyl guaiacol predominated in Teucrium flavum. Carvacrol and caryophyllene oxide predominated in Teucrium montbretii ssp. heliotropiifolium, while carvacrol and caryophyllene were the most abundant components in Teucrium polium ssp. capitatum. The oil which most effectively inhibited LPS-induced NO production in macrophage cell line RAW 264.7 was that from T. brevifolium (IC₅₀ = 7.1 μg/ml), followed by T. montbretii ssp. heliotropiifolium and T. polium ssp. capitatum (IC₅₀ = 16.5 and 29.4 μg/ml, respectively). The in vitro cytotoxic assay on three human cancer cell lines showed that the most antiproliferative oils were those from T. polium ssp. capitatum and T. montbretii ssp. heliotropiifolium on CACO-2 cell lines (IC₅₀ = 52.7 and 92.2 μg/ml, respectively). The T. brevifolium oil showed a selective cytotoxicity on COR-L23 while significant activity was exerted by T. polium oil on C32.     

Screening of the antioxidative and antimicrobial properties of the essential oils of Pimpinella anisetum and Pimpinella flabellifolia from Turkey

The aerial parts of two endemic Pimpinella [Pimpinella anisetum Boiss. & Ball. and Pimpinella flabellifolia (Boiss.) Benth. ex Drude] were hydro-distilled to produce oils in the yields of 2.07% (v/w) and 2.61% (v/w), respectively. The oils were analysed by GC and GC/MS. Twenty-one and nineteen components were identified, representing 99.5% and 99.7% of the oils, respectively. The main compounds of P. anisetum were (E)-anethole (82.8%) and methyl chavicol (14.5%), whereas limonene (47.0%), (E)-anethole (37.9%) and α-pinene (6.0%) were the major constituents of P. flabellifolia. The oils were screened for their possible antioxidant activities by two complementary test systems, namely DPPH free radical-scavenging and β-carotene/linoleic acid systems. In the first case, P. anisetum oil exerted greater antioxidant activity than that of P. flabellifolia oil with an IC₅₀ value of 5.62 ± 1.34 μg/ml. In the β-carotene/linoleic acid test system, the oil of P. anisetum was superior to P. flabellifolia with 70.5% ± 2.86 inhibition rate. Essential oils of the plants studied here were also screened for their antimicrobial activities against six bacteria and two fungi. The oils showed moderate antimicrobial activity against all microorganisms tested.     

Comparative chemical composition,antioxidant and hypoglycaemic activities of Juniperus oxycedrus ssp. oxycedrus L. berry and wood oils from Lebanon

Juniper (Juniperus oxycedrus) is used in European cuisine for its distinguishing flavour. J. oxycedrus ssp. oxycedrus berry and wood essential oils were tentatively identified by GC and GC/MS. Fifty compounds were identified in the berry oil and 23 compounds were identified in the wood oil. The J. oxycedrus ssp. oxycedrus berry oil was characterised by high contents of α-pinene (27.4%) and β-myrcene (18.9%). Other important compounds were α-phellandrene (7.1%), limonene (6.7%), epi-bicyclosesquiphellandrene (2.3%) and δ-cadinene (2.2%) while, in the wood oil, δ-cadinene (14.5%) is a major main component, together with cis-thujopsene (9.2%) and α-muurolene (4.9%). In vitro evaluation of antioxidant activity by the DPPH method showed a significant activity for both oils with IC₅₀ values of 1.45 μl/ml for wood and 7.42 μl/ml for berries. Hypoglycaemic activity was investigated through the inhibition of α-amylase. The results revealed that oil obtained by hydrodistillation from J. oxycedrus ssp. oxycedrus wood exhibits an interesting activity with IC₅₀ of 3.49 μl/ml.     

Chemical composition and antifungal activity of essential oils from three Himalayan Erigeron species

Three Himalayan Erigeron (Asteraceae) species viz Erigeron mucronatus, Erigeron annuus and Erigeron karwinskianus growing in sub-alpine region revealed occurrence of isomeric polyacetylenic constituents viz., matricaria and lachnophyllum esters which accounted for 83.3%, 69.3% and 30.1% of the essential oils from these species, respectively, in addition to mono- and sesquiterpenoids as minor constituents. The antifungal activity tested by poisoned food (PF) techniques against Fusarium oxysporum, Helminthosporium maydis, Rhizoctonia solani, Alternaria solani and Sclerotinia sclerotiorum demonstrated significant inhibition of the mycelial growth of all strains (p < 0.05). The oils (500 μg/mL) showed significant antifungal effect against tested fungi in the growth inhibition range of 37.6–85.5% with respective IC₅₀ values ranging from 88.8 to 660.0 μg/mL as compared to standard fungicides (100% inhibition) with IC₅₀ value in the range of 32.2–129.4 μg/mL. Significant inhibition of spore germination was noticed for F. oxysporum, Curvularia lunata and Albugo candida which were highly susceptible to E. annuus oil with their IC₅₀ values 120.7, 253.5 and 300.4 μg/mL, respectively. Thus, the results obtained in this study demonstrate the potential of essential oils from Himalayan Erigeron species as non-toxic, eco-friendly and biodegradable natural fungicides.     

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.     

Antimicrobial activities of methanol extracts and essential oils of Rosmarinus officinalis, depending on location and seasonal variations

Rosmarinus officinalis is widely found in the lands of Aegean and Mediterranean regions of Turkey. The goal of this work was to test the antimicrobial activity of the essential oils and methanolic extracts of R. officinalis collected from three different regions at four different time intervals of the year against Staphylococcus aureus, Proteus vulgaris, Pseudomonas aeruginosa, Klebsiella pneumonia, Enterococcus feacalis, Escherichia coli, Staphylococcus epidermidis, Bacillus subtilis and Candida albicans. Essential oils were obtained from the aerial parts of the plant by using a Clevenger apparatus, for 4 h. After distillation, the distillates were filtered, air-dried and then extracted by using a Soxhlet apparatus for 9 h to obtain the methanolic extracts. The antimicrobial activities of the methanolic extracts were tested by the disc diffusion technique. The antimicrobial activities of the essential oils obtained from R. officinalis were determined by minimum inhibitory concentration (MIC).The results indicated that the tested bacteria were sensitive to the essential oils and partially to the methanolic extracts. The antimicrobial activities of the essential oils against the tested bacteria differed, depending on location and seasonal variations.     

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 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.     

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.