Chemical composition,antimicrobial, and cytotoxicity studies on S. erianthum and S. macranthum essential oils

Context: Solanum erianthum D. Don and Solanum macranthum Dunal (Solanaceae) are widely used in traditional medicine. The leaves act as an abortifacient and in particular to treat leucorrhoea, sores, and skin irritations.

Objective: This study was undertaken to characterize the volatile constituents of the leaf and fruit essential oils of S. erianthum and S. macranthum; their antimicrobial and in vitro cytotoxic bioassay against human breast and prostate tumor cells.

Methods: The volatile oils were obtained by hydrodistillation and analyzed for their constituents by gas chromatography-mass spectrometry (GC-MS). Minimum Inhibitory Concentrations (MIC) were determined using the microbroth dilution technique while the cytotoxic potentials were evaluated using the Cell Titre 96^(R) AQ_ueous Non-Radioactive Cell Proliferation Assay method.

Results: Solanum erianthum essential oils were characterized by the abundance of α-terpinolene (17.8%), α-phellandrene (17.5%), p-cymene (15.7%) and β-pinene (11.7%) in the leaves; α-humulene (23.1%), humulene epoxide II (20.0%), caryophyllene oxide (16.5%), methyl salicylate (11.8%) and β-caryophyllene (10.9%) in the fruits. The leaf oil of S. macranthum consisted of (E)-phytol (29.0%), pentadecanal (28.1%) and pentadecane (7.7%) while the major fruit oil constituents were α-humulene (36.5%), β-caryophyllene (17.8%), ethyl palmitate (9.4%), and methyl salicylate (8.2%). Solanum erianthum leaf volatile oil demonstrated potent inhibitory activity against Hs 578T and PC-3 human breast and prostate tumor cells respectively. In addition, the Solanum essential oils exhibited significant antimicrobial activity (19.5–625 µg/mL) on pathogens employed in the assay.

Conclusion: The Solanum essential oils possess strong antimicrobial activity in addition to the potent cytotoxic potential of S. erianthum leaf oil against Hs 578T and PC-3 cells.     

Chemical Composition of Essential Oils from Leaves and Twigs of Pistacia lentiscus,Pistacia lentiscus var. chia,and Pistacia terebinthus from Turkey

The composition of the essential oils from the leaves and twigs of Pistacia lentiscus L., Pistacia lentiscus var. chia (L.), and Pistacia terebinthus L. of Turkish origin were analyzed by gas chromatography/mass spectrometry (GC/MS). Seventy-seven constituents were characterized from the essential oil of P. terebinthus leaves with α-cadinol (6.9%), phytol (5.4%), δ-cadinene (5.1%), α-terpineol (5.0%), and bornyl acetate (4.4%) as major constituents. Germacrene D (10%), β-pinene (7.5%), bornyl acetate (6.0%), α-cubebene (5.9%), and cubebol (5.4%) were found to be the main components among the 61 compounds characterized in the essential oil of P. terebinthus twigs. Forty-six compounds were characterized from the essential oil of P. lentiscus twigs with sabinene (23.2%), α-pinene (19.4%), germacrene D (14.1%), limonene (6.9%), β-phellandrene (6.5%), terpinene-4-ol (5.7%), and β-caryophyllene (5.7%) as the main constituents. Terpinene-4-ol (29.2%), β-caryophyllene (29.2%), and p-cymene (7.1%) were identified as the major components among the 64 compounds characterized in the essential oil of P. lentiscus leaves. Sixty-eight compounds were found on the essential oil of P. lentiscus var. chia leaves with germacrene D (20.1%), myrcene (13.9%), β-caryophyllene (10.8%), and α-terpinyl acetate (4.8%) as the major constituents. Myrcene (27.4%), germacrene D (21.7%), and β-caryophyllene (7.2%) were found to be the main components among 50 compounds characterized in the essential oil of P. lentiscus var. chia twigs.     

A study of the larvicidal activity of two Croton species from northeastern Brazil against Aedes aegypti

The essential oils of Croton heliotropiifolius Kunth (Euphorbiaceae) and Croton pulegiodorus Baill. were selected for larvicidal evaluation against Aedes aegypti L. (Diptera: Culicidae) and studied qualitatively and quantitatively by GC and GC-MS. Sixty-one compounds representing 92.03% (C. heliotropiifolius) and 85.68% (C. pulegiodorus) of the essential oils, respectively, have been identified. The major components of C. heliotropiifolius essential oil were identified as β-caryophyllene (35.82%), bicyclogermacrene (19.98%), and germacrene-D (11.85%). The major components in C. pulegiodorus essential oil were identified as β-caryophyllene (20.96%), bicyclogermacrene (16.89%), germacrene-D (10.55%), τ-cadinol (4.56%), and β-copaen-4-α-ol (4.35%). The essential oil of C. pulegiodorus (LC₅₀ 159 ppm) was more effective against Ae. aegypti than that of C. heliotropiifolius (LC₅₀ 544 ppm). In order to verify whether the major compound of both essential oils is the active principle responsible for the larvicidal activity, β-caryophyllene was purchased and its larvicidal potential was further evaluated. However, β-caryophyllene (LC₅₀ 1038 ppm) showed weak larvicidal potency. Results of larvicidal evaluation suggest the existence of a synergistic effect of minor components in the essential oils.     

Chemical composition and bioactivity of essential oils of Hypericum helianthemoides. Hypericum perforatum and Hypericum scabrum

Context: A number Hypericum species are well known for their therapeutic efficacy and use in traditional medicine. The various species of Hypericum have been traditionally used for the treatment of wounds, eczema, burns, trauma, rheumatism, neuralgia, gastroenteritis, ulcers, hysteria, bedwetting and depression.

Objective: This study evaluated the in vitro antioxidant, antibacterial and phytochemical properties of essential oils of Hypericum helianthemoides (Spach) Boiss., Hypericum perforatum L. and Hypericum scabrum L. (Hypericaceae) collected from alpine region of Southwest Iran.

Materials and methods: The essential oils obtained from dried flowering aerial parts of three Hypericum species were analyzed by gas chromatography and gas chromatography/mass spectrometry to determine chemical compositions. The antibacterial activity of essential oils within concentration ranges from 16 to 500?µg/mL was individually evaluated against Bacillus cereus, Listeria monocytogenes. Proteus vulgaris and Salmonella typhimurium. The 1,1-diphenyl-2-picrilhydrazyl (DPPH) radical scavenging activity of essential oils was determined using DPPH assay.

Results: Essential oil yield of H. helianthemoides. H. scabrum and H. perforatum were 0.12, 0.20 and 0.21?mL/100?g dried material, respectively. The major constituents of the essential oils were α-pinene (12.52–49.96%), β-pinene (6.34–9.70%), (E)-β-ocimene (4.44–12.54%), β-caryophyllene (1.19–5.67%), and germacrene-D (2.34–6.92%). The essential oils of three Hypericum species indicated moderate-to-good inhibitory activities against four bacteria, especially against L. monocytogenes.

Discussion and conclusion: The essential oils of the three studied Hypericum species sourced in alpine region of West Iran were rich in monoterpene and sesquiterpenes hydrocarbons. Among the three tested species, the essential oil of H. scabrum showed the highest antibacterial and antioxidant activities.     

Anti-inflammatory activity of essential oil from leaves of Myrciaria tenella and Calycorectes sellowianus

The GC-MS analysis revealed that the leaf essential oils of Myrciaria tenella (DC.) Berg and Calycorectes sellowianus O. Berg (Myrtaceae) were composed of 34 and 37 compounds, respectively. The main constituents of M. tenella oil were β-caryophyllene (25.1%), and spathulenol (9.7%), while for C. sellowianus were guaiol (13.1%) and β-caryophyllene (8.6%). The anti-inflammatory effect of both essential oils was investigated in vitro and in vivo. Both oils reduced significantly (p < 0.005) the treated neutrophils chemotaxis with 93% and 91% inhibition for M. tenella and C. sellowianus, respectively. However, in the systemic treatment with the essential oils (50?mg/kg p.o.) only the M. tenella oil was able to significantly reduce the carrageenan-induced paw edema with a similar effect to that observed for indomethacin (10?mg/kg), the positive control.     

Chemical composition and antibacterial activity of essential oils of <Emphasis Type="Italic">Eugenia</Emphasis> species

The essential oils of the leaves of Eugenia brasiliensis, Eugenia beaurepaireana, and Eugenia umbelliflora were analyzed by GC–MS. The major compounds found in the oil of E. brasiliensis were spathulenol (12.6%) and τ-cadinol (8.7%), of E. beaurepaireana were β-caryophyllene (8.0%) and bicyclogermacrene (7.2%), and of E. umbelliflora were viridiflorol (17.7%) and β-pinene (13.2%). These oils were assayed to determine their antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. All of the oils analyzed showed antibacterial activity, ranging from moderate to strong, which was most accentuated for the E. umbelliflora and E. brasiliensis oils, which strongly inhibited the growth of S. aureus giving values of MIC = 119.2 and 156.2 μg/mL, respectively.     

Composition and antibacterial activity of the essential oil of Satureja parnassica subsp parnassica

The essential oils of Satureja parnassica subsp. parnassica (samples A and B), were analyzed by means of GC/MS. From the fifty-seven identified constituents representing 98.5 % and 99.35 % of the oils respectively, ( E)-caryophyllene, carvacrol and caryophyllene oxide were the major components of sample A (flowering stage), whereas in sample B (vegetative stage) major components were spathulenol, p-cymene and linalool. The oils were tested against Helicobacter pylori (HP), as well as against six aerobically growing bacteria. Both samples showed a moderate activity against Gram-positive bacteria; sample A oil showed greater anti-HP activity than sample B.     

Chemical composition, antimicrobial and antioxidant activities of essential oil from Gnaphlium affine

The chemical composition of the essential oil from Gnaphlium affine was determined, and its antimicrobial and antioxidant activities were evaluated. Twenty-four compounds, representing 94.95% of the amount of total oil, were identified by gas chromatography-mass spectrometry (GC-MS) analysis. Main constituents of the essential oil were found to be eugenol (18.24%), linalool (10.62%), trans-caryophyllene (8.86%), α-terpineol (5.97%), p-cymene (5.75%), hexadecanoic acid (5.63%), γ-cadinene (4.98%), δ-cadinene (4.22%), α-humulene (3.22%), and (−)-β-elemene (3.15%). The essential oil revealed a remarkable antimicrobial effect against the tested food-borne microorganisms with the MIC and MBC values in the ranges of 0.2-1.56 μg/ml and 0.39-3.13 μg/ml, respectively. The essential oil showed a potent antioxidant activity in ABTS radical scavenging, lipid peroxidation and reducing power assay. It was suggested that the essential oil from G. affine may be a new potential source as natural antimicrobial and antioxidant agents applied in food systems.     

Chemical Composition and Antibacterial Activity of the Essential Oil of Centella asiatica. Growing in South Africa

ABSTRACT

In South Africa, Centella asiatica. (L.) Urb is used traditionally for the treatment of various diseases. Analyses of the essential oil of this medicinal plant revealed 11 monoterpenoid hydrocarbons (20.20%), nine oxygenated monoterpenoids (5.46%), 14 sesquiterpenoid hydrocarbons (68.80%), five oxygenated sesquiterpenoids (3.90%), and one sulfide sesquiterpenoid (0.76%). α.-Humulene (21.06%), β.-caryophyllene (19.08%), bicyclogermacrene (11.22%), germacrene B (6.29%), and myrcene (6.55%) were the predominant constitutes. The essential oil extract exhibited a broad spectrum of antibacterial activities against Gram-positive (Bacillus subtilis, Staphylococcus aureus.) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Shigella sonnei.) organisms.     

Chemical composition,antioxidant and antibacterial activities of essential oils from Ferulago angulata

Context: Ferulago angulata Boiss. (Apiaceae), a perennial aromatic herb, grows wild in Iran. The aerial parts of F. angulata are used as a flavouring in foods, especially dairy foods by indigenous people in western and southwestern Iran.

Objective: This study investigates variation in chemical compositions, antioxidant and antibacterial activities of the essential oils from F. angulata collected from natural habitats in the alpine regions of southwestern Iran.

Materials and Methods: The antimicrobial activity, minimum inhibitory concentration (MIC) and minimum bactericidal (MBC) of the essential oils were evaluated against four bacteria (Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus and Salmonella typhimurium). Antioxidant activity of the oils was determined by DPPH assay.

Results: The essential oils were analyzed by GC-FID and GC/MS, which 49 volatile components were identified. There were significant differences between the various populations for oil yield and some main compounds. The major constituents of the essential oils from F. angulata were α-pinene, and cis-β-ocimene. The MICs of the essential oils were within concentration ranges from 62 to 250?μg/mL and the respective MBCs were 125 to?>?500?μg/mL. Generally, the oils from F. angulata indicated weak to moderate inhibitory activities against bacteria, especially against Listeria monocytogenes. The highest antioxidant activity was obtained from the oil of the Kallar population (IC₅₀ value_?=_?488?μg/mL) and BHT as positive control (IC_50? value =_?321?μg/mL).

Discussion and conclusion: The essential oil of F. angulata could be serving as a potential source of α-pinene and cis-β-ocimene for use in the food, cosmetic and pharmaceutical industries.     

Chemical composition and cytotoxic activity of the leaf essential oil of <Emphasis Type="Italic">Eugenia zuchowskiae</Emphasis> from Monteverde,Costa Rica

The leaf essential oil of Eugenia zuchowskiae from Monteverde, Costa Rica, has been obtained by hydrodistillation and analyzed by GC–MS. The principal constituents of E. zuchowskiae leaf oil were α-pinene (28.3%), β-caryophyllene (13.2%), α-humulene (13.1%), and α-copaene (8.1%). The leaf essential oil of E. zuchowskiae showed pronounced in-vitro cytotoxic activity against MCF-7, MDA-MB-468, and UACC-257 human tumor cell lines. The major components showed cytotoxic activities comparable to doxorubicin (LC₅₀ 14–70 μg/ml).     

Essential Oil Composition and Antibacterial Studies of Vitex negundo Linn. Extracts

Essential oils from fresh leaves, flowers and dried fruits of Vitex negundo were obtained by hydrodistillation. Using Soxhlet extractor five successive extracts from dried and powdered leaves were also taken. The chemical constituents of essential oil of leaves, flowers and dried fruits were analyzed by GC-FID and GC/MS techniques. Main constituents identified in leaves oil were δ-guaiene, carryophyllene epoxide and ethyl-hexadecenoate; in flowers oil - α-selinene, germacren-4-ol, carryophyllene epoxide and (E)-nerolidol while fruit oil showed β-selinene, α-cedrene, germacrene D and hexadecanoic acid as the main constituents. β-Caryophyllene was only the constituent identified as common to all three oils. α-Guaiene and guaia-3,7-diene were identified as common constituents in leaf and dried fruit oil while leaf and flower oils showed p -cymene, valencene, caryophyllene epoxide and (E)-nerolidol as common constituent. All the essential oils and successive extracts were evaluated for antibacterial potential against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa bacterial strains. Each of the essential oils and extracts were found to give promising results against B. subtilis and E. coli. Ethyl acetate and ethanol extracts showed prominent antibacterial activity against all the tested strains. Fruits and leaves oil were found to be most active against E. coli and S. aureus, respectively. Only flowers oil was found to be active against P. aeruginosa.     

Identification of the main volatile compounds in the leaf and flower of <Emphasis Type="Italic">Tithonia diversifolia</Emphasis> (Hemsl) Gray

The composition of the essential oils of the leaves and flowers of Tithonia diversifolia (Hemsl) A. Gray, Mexican sunflower, are reported. The oils were obtained by hydrodistillation in an all-glass Clevenger-type apparatus and analyzed by GC–MS. The leaf oil was comprised of an abundance of α-pinene (32.9%), β-caryophyllene (20.8%), germacrene D (12.6%), β-pinene (10.9%) and 1, 8-cineole (9.1%). Germacrene D (20.3%), β-caryophyllene (20.1%) and bicyclogermacrene (8.0%) characterized the oil of the flower. A number of aliphatic fatty acids and a diterpenoid compound, sandaracopimaradiene, that were present in the flower, could not be detected in the leaf oil.     

Antimicrobial activity and chemical composition of the essential oil of Hofmeisteria schaffneri

Objectives The aims of this study were to establish the antimicrobial potential of Hofmeisteria schaffneri essential oil and its chemical composition. Methods The essential oils of Hofmeisteria schaffneri harvested at flowering (batches I and IV) and non‐flowering (batches II and III) seasons were prepared by hydrodistillation and analysed by GC and GC‐MS. The aqueous and organic (CH₂Cl₂‐MeOH 1 : 1) extracts were prepared by using infusion and maceration techniques, respectively. The in‐vitro antimicrobial activity of the preparations and compounds against Candida albicans and some bacteria (Gram‐negative and Gram‐positive) was assessed using the broth dilution method in 96‐microplate wells. Key findings Forty‐four compounds, representing ～90% of the total constituents, were identified in the essential oil of Hofmeisteria schaffneri collected in flowering (batches I and IV) and non‐flowering (batches II and III) seasons. In all cases, several thymol analogues were the major components of the oils (～65%); some small differences in the relative proportions of these constituents were observed. The infusion exhibited an antibacterial activity against Staphylococcus aureus and Bacillus subtilis, with a MIC value of 64 µg/ml in each case. The essential oil batches were active against Staphylococcus aureus, with MIC ranging from 48 to 192 µg/ml. They were, however, inactive against Gram‐negative bacteria, including Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi (MIC > 1024 µg/ml). On the other hand, the infusion of the plant as well as the oil from batch I displayed anti‐Candida albicans activity, with MIC of 128 and 192 µg/ml, respectively. Finally, the organic extract did not displayed significant activity against the tested microorganisms (MIC ≥ 1024 µg/ml). Some of the compounds isolated from the plant were also tested. Compounds 8 and 38, which were present in the essential oils, displayed the best antibacterial effect against Gram‐positive bacteria (MIC ranging between 32 and 64 µg/ml). Compounds 6 (present in the infusion) and 10 (present in all preparations) showed higher activity against the yeast (MIC = 128 µg/ml) than the remaining compounds, with MIC values ranging from 256 to 512 µg/ml. Conclusions The composition and antimicrobial activity of the oils changed slightly from flowering to non‐flowering seasons. The results of the present investigation provide in‐vitro scientific support for the use of the plant against skin infections in Mexican folk medicine.     

蜡梅不同部位精油化学成分分析及其体外抑菌活性研究

目的 研究蜡梅Chimonanthus praecox（Linn.）Link根、叶、果皮中精油的化学组成及其抑菌活性。方法 采用气相色谱-质谱联用（GC-MS）技术对水蒸气蒸馏法提取的蜡梅根、叶、果皮精油进行成分分析,并分别采用肉汤二倍稀释法和菌丝生长法测试蜡梅不同部位精油对细菌和病原真菌的抑制活性。结果 鉴定了蜡梅根精油中的37种成分、蜡梅叶精油中的48种成分、蜡梅果皮精油中的38种成分,蜡酶不同部位精油中具有相同的化合物15种,分别占各部位精油总量的84.05%,36.83%,64.46%。抑菌实验结果表明蜡梅不同部位精油对受试菌均有不同强度的抑制作用。结论 蜡梅根精油对革兰氏阳性菌和病原真菌具有较强的抑菌活性,抑菌谱较广,且该精油含有多种生物活性成分,具有较高的药用价值及开发前景。     

Chemical composition,antibacterial activity and cytotoxicity of essential oils of Tanacetum parthenium in different developmental stages

Context: Tanacetum parthenium Schultz Bip. (Asteraceae) is an aromatic perennial plant, widely distributed in the northern hemisphere. This species traditionally has been used in insecticides, cosmetics, balsams, dyes, medicines and preservatives.

Material and methods: The essential oil of T. parthenium was obtained by hydrodistillation in three developmental stages and analyzed by gas chromatography-mass spectrometry. The antibacterial activity of the oils was investigated against four Gram-positive and four Gram-negative bacteria. The oil was tested for cytotoxicity against THP-1 cells using the Trypan blue assay.

Results: Twenty-nine components were identified in the essential oil; the highest amount was extracted at the flowering stage. The main component, in the flowering stage, was camphor (18.94%) and other major components were bornyl acetate (18.35%), camphene (13.74%), bornyl isovalerate (3.15%), borneol (10.93%), juniper camphor (6.23%) and β-eudesmol (2.65%). Minimum inhibitory concentration of essential oil was evaluated from 4 µL mL^?1 against Staphylococcus subtilis to 38 µL mL^?1 against Entrobacter aerogenes. Toxicity assay showed that the oil has no significant toxicity at 5–15% v/v concentrations on THP-1 cells.

Discussion and conclusion: This study demonstrates the occurrence of camphor/bornyl acetate chemotype of T. parthenium in western regions of Iran. The finding showed also the studied oils have relatively good antibacterial activity without significant toxicity, thus have great potentiality to be used as natural health product.     

Analysis of the essential oil from the aerial parts of Psoralea pubescence (Miq.) Standl and its antibacterial activity

The essential oil from aerial parts of Psoralea pubescence (Miq.) Standl (Leguminoseae) was analyzed by gas chromatography (GC) and GC/mass spectroscopy systems. The major components identified were psoralen (24.8%), bakuchiol (21.3%), β-caryophyllene (8.5%), germacrene D (6.8%), and α-humulene (4.6%). The major volatiles released by β-glucosidase treatment of the aqueous plant residue were δ-pinene (28.3%), germacrene D (13.6%), and tricyclene (10.2%). The oil showed significant antibacterial activity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, and Pseudomonas aeruginosa, while the β-glucosidase-liberated fraction was inactive.     

Antibacterial properties of essential oils and methanol extracts of sweet basil Ocimum basilicum occurring in Bangladesh

The antibacterial potential of essential oils and methanol extracts of sweet basil Ocimum basilicum L. (Lamiaceae) was evaluated for controlling the growth range of food-borne pathogenic bacteria. Essential oils extracted by hydrodistillation from the leaves and stems were analyzed by GC-MS. Fifty-seven compounds representing 94.9 and 96.1% of the total leaf and stem oils, respectively, were identified, of which methyl chavicol (36.7 and 29.9%), gitoxigenin (9.3 and 10.2%), trimethoquinol (10.3 and 8.4%), β-guaiene (3.7 and 4.1%), aciphyllene (3.4 and 3.0%), alizarin (3.2 and 4.4%), naphthaline (2.2 and 3.8%), (–)-caryophyllene (2.0 and 1.9%), and mequinol (1.6 and 1.8%) were the major compounds. The essential oils (10?μL/disc of 1:5, v/v dilution with methanol) and methanol extracts (300?μg/disc) of O. basilicum displayed a great potential of antibacterial activity against Bacillius cereus, B. subtilis, B. megaterium, Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Shigella boydii, S. dysenteriae, Vibrio parahaemolyticus, V. mimicus, and Salmonella typhi with their respective zones of inhibition of 11.2–21.1?mm and MIC values of 62.5–500?μg/mL. The results of this study suggest that the natural products derived from O. basilicum may have potential use in the food and/or pharmaceutical industries as antimicrobial agents.     

Chemical composition and antibacterial activity of essential oils of Tripleurospermum disciforme in three developmental stages

Context: Tripleurospermum disciforme (C.A. Mey) Schultz Bip. (Asteraceae) is a widespread biennial species which also has traditional medicinal uses. According to the few recent studies, essential oils of this species exhibit anti-inflammatory, antispasmodic, antiseptic, antifungal, antiulcer, and antioxidant activity.

Objective: The chemical compositions of the hydrodistilled oils of T. disciforme of Iranian origin are studied in the stages of prior to flowering, flowering, and post flowering, for the first time. Also, we investigated the antibacterial activities of the oils.

Materials and methods: The essential oils of air-dried T. disciforme were obtained by hydrodistillation in three different developmental stages and analyzed by gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity of the isolated essential oil, in the three stages, was also investigated against four Gram-positive and four Gram-negative bacteria.

Results: Twenty-one components were identified in the essential oils of T. disciforme, and the highest amount of oil was extracted at the flowering stage. The main component of the species in the flowering stage was β-farnesene (22.46%) and the other major components were β-sesquiphellandrene (17.85%), p-methoxy-β-cyclopropylstyrene (16.64%), heptadecane (10.6%), p-methoxy-humulene oxide (6.88%) and benzene acetaldehyde (9.3%). The MIC of essential oil was evaluated from 4 µL ml^?1 against Staphylococcus subtilis and Bacillus cereus to 22 µL ml^?1 against Citrobacter amalonaticus.

Discussion and conclusion: This study demonstrates the occurrence of β-farnesene/β-sesquiphellandrene chemotype of T. disciforme in western regions of Iran that are different from previous reports. The findings also showed that the essential oils T. disciforme have excellent antibacterial activities and thus have great potentiality to be used as a resource for natural health products.     

Composition and antibacterial activity of the essential oils of Stachys candida and S. chrysantha from southern Greece

The chemical composition of the essential oils obtained from the aerial parts of Stachys candida and S. chrysantha were analysed with GC and GC/MS. Forty-two constituents were identified from the two oils and alpha-cadinol, manoyl oxide, caryophyllene oxide, epi-alpha-muurolol and (E)-caryophyllene were found to be the major components. Furthermore, the oils were tested against six Gram (+/-) bacteria and it was found that one of them exhibited significant antibacterial activity.