What Socrates drank? Comparative chemical investigation of two Greek Conium taxa exhibiting diverse chemical profiles.

Conium divaricatum, even though exhibiting morphological differences in comparison to its congener of European origin Conium maculatum, is still considered a disputed taxon often referred to as a synonym of the latter. Herein, essential oils of various plant tissues from several populations of both taxa were comparatively investigated, showing distinct chemical profiles. In the case of C. divaricatum, the essential oils were dominated by hydrocarbon esters, among which the main constituents 4'-oxodecyl hexanoate, 4'-oxododecyl hexanoate and 4'-oxooctyl hexanoate were isolated and identified as undescribed natural products. In contrast, the essential oils of C. maculatum were dominated by hydrocarbon alkanes, alkenes and ketones, as well as the polyacetylene (Z)-falcarinol. Even though determination of the total alkaloids content and toxicity assessment against the crustacean Artemia salina did not reveal significant differences, the distinct chemical profiles and the morphological differences observed for both taxa, strongly support their distinction as separate species.

Chemical Composition of Juniperus phoenicea and J. drupacea Essential Oils and their Biological Effects in the Choriallantoic Membrane (CAM) Assay.

The aim of the present study was the chemical analysis of the essential oils from Juniperus phoenicea and J. drupacea female cones and evaluation of their biological effects. Fresh samples, collected in Greece, were subjected separately to hydrodistillation and the oils obtained analyzed by GC-FID and GC-MS. The oils Were assessed using the CAM (chorioallantoic membrane) assay to evaluate their anti-angiogenic potential and the lack of irritant effects in topical application. GC analysis showed that mainly quantitative differences among the samples were observed: limonene was the most abundant compound in J. drupacea (27.0%) compared with J. phoenicea oil (1.6%); the content of a-pinene was high in both essential oils (J. phoenicea 22.1%, J. drpacea 26.1%) followed by germacrene D (J. phoenicea 7.4%, J. drpacea 7.1%, respectively). Nevertheless, qualitative differences were also detected as the diterpene 4-epi-abietal was present in a considerable amount (13.2%) in J. phoenicea essential oil, but was not detected in J. drupacea oil. In the CAM assay, only J. phoenicea. essential oil evidenced a rather weak anti-angiogenic activity compared with the standard retinoic acid, but no irritant effect was observed for either essential oil suggesting their safety for topical application.

Chemical Composition and Larvicidal Activity of Greek Myrtle Essential Oils against Culex pipiens biotype molestus.

Fresh leaves of Myrtus communis collected from different localities in Greece, were subjected to hydrodistillation and the oils obtained were analyzed by GC-FID and GC-MS. The analyses showed mainly quantitative differences, with the monoterpenes myrtenyl acetate, α-pinene, 1,8-cineole, and linalool, along with limonene, dominating the majority of the analyzed Myrtle oils. The evaluation of the larvicidal activity of the samples against Culex pipiens biotype molestus mosquito showed that all tested samples exhibited moderate to weak toxicity, with cultivated M. communis subsp. communis oil being the most active.

Greek Pinus essential oils: larvicidal activity and repellency against Aedes albopictus (Diptera: Culicidae).

The needle volatiles metabolites of seven Pinus spp.: Pinus nigra (3 samples), Pinus stankewiczii, Pinus brutia, Pinus halepensis, Pinus canariensis, Pinus pinaster and Pinus strobus from Greece were determined by gas chromatography and gas chromatography-mass spectrometry. P. nigra and P. canariensis essential oils were dominated by α-pinene (24.9-28.9 % and 15 %, respectively) and germacrene D (20.3-31.9 % and 55.8 %, respectively), whereas P. brutia and P. strobus by α-pinene (20.6 % and 31.4 %, respectively) and ß-pinene (31.7 % and 33.6 %, respectively). P. halepensis and P. pinaster oils were characterized by ß-caryophyllene (28.5 % and 22.5 %, respectively). Finally, ß-pinene (31.4 %), germacrene D (23.3 %) and α-pinene (17.5 %) were the most abundant compounds in the needle oil of P. stankewiczii. Additionally the larvicidal and repellent properties of their essential oils were evaluated against Aedes albopictus, a mosquito of great ecological and medical importance. The results of bioassays revealed that repellent abilities of the tested essential oils were more potent than their larvicidal activities. The essential oils of P. brutia, P. halepensis and P. stankewiczii presented considerable larvicidal activity (LC50 values 67.04 mgL(-1) and 70.21 mgL(-1), respectively), while the others were weak to inactive against larvae. The essential oils of P. halepensis, P. brutia, and P. stankewiczii presented a high repellent activity, even at the dose of 0.2 µL cm(-2), while in the dose of 0.4 µL cm(-2), almost all the tested EOs displayed protection against the mosquito.

Secondary metabolites from Asperula lutea subsp. rigidula.

From the aerial parts of Asperula lutea subsp. rigidula (Halacsy) Ehrend., an endemic plant of south-eastern Greece, nine known compounds, beta-sitosterol, geniposidic acid, deacetyl-asperuloside, scandoside, chlorogenic acid, quercetin, hyperin, isoquercitrin and rutin, were isolated. From the analysis of a non polar fraction of the methanolic extract by means of GC and GC-MS, eighteen compounds were identified, mainly esters of fatty acids. The major components were the ethyl esters ofpalmitic acid (32.7%), linolenic acid (20.1%) and linoleic acid (10.5%).

Chemical composition and antimicrobial activity of Anthriscus nemorosa root essential oil.

The essential oil obtained by hydrodistillation from the roots of Anthriscus nemorosa (Bieb.) Sprengel (Umbelliferae) was analyzed by GC and GC-MS. Among sixty-two compounds identified (representing 89.0% of the total oil), the main components were: n-nonane (12.1%), n-hexadecanol (6.9%), delta-cadinene (6.4%), beta-pinene (6.0%) and germacrene D (5.4%). Furthermore, the antimicrobial activity of the oil was evaluated against the Gram-positive bacteria Staphylococcus epidermidis (ATCC 12228) and Bacillus subtilis (ATCC 6633), the Gram-negative bacterium Escherichia coli (ATCC 25922), and a yeast Candida albicans (ATCC 10259 and ATCC 24433) using the broth microdilution method.

Antimicrobial activity of the essential oil of Greek endemic Stachys spruneri and its main component, isoabienol.

The essential oils of Stachys spruneri Boiss. (sample A and sample B) were analyzed by GC and GC-MS. (+)-Isoabienol was the dominant component (49.5 and 48.2%, respectively of the total oils) among seventy-two identified constituents. Isoabienol was separated, purified by preparative thin-layer chromatography, and further identified by means ofphysicochemical and spectrometric analysis. The microbial growth inhibitory properties of the essential oil and its main metabolite, the labdane diterpene isoabienol, were determined using the broth microdilution method against eight laboratory strains of bacteria (Gram-positive: Staphylococcus aureus, S. epidermidis, Micrococcus luteus, Enterococcus faecalis, Bacillus subtilis, and Gram- negative: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and two strains of the yeast Candida albicans. Both essential oil and isoabienol showed considerable activity against all the microorganisms tested, with the isolated compound being most active.

Chemical composition and biological activities of Calamintha officinalis Moench essential oil.

Calamintha officinalis Moench essential oil is used in cooking as an aromatic herb and also to improve the flavor and fragrance of several pharmaceutical products. The essential oil, obtained by hydrodistillation (5 mL/kg), was analyzed by gas chromatography-mass spectrometry and gas chromatography-flame ionization detection. Sixty-four components were identified, constituting 99.7% of the total oil. The major component was found to be carvone (38.7%), followed by neo-dihydrocarveol (9.9%), dihydrocarveol acetate (7.6%), dihydrocarveol (6.9%), 1,8 cineole (6.4%), cis-carvyl acetate (6.1%), and pulegone (4.1%). The essential oil showed antifungal and antimicrobial activity against Gram-positive bacteria. In addition, it presented a very low toxicity both in vivo (50% lethal dose >100 mg/kg) and in vitro in the Artemia salina test (50% lethal concentration >500 µL/mL). C. officinalis essential oil, in rodents, produces the typical effects in behavior of a nonselective central nervous system-depressant drug; it potentiates the hypnotic effects of sodium pentobarbital, decreasing the induction time and enhancing the sleeping time. Moreover, it produces a decrease in body temperature and a protection against pentylenetetrazole-induced convulsions.

Antioxidant activity of Nepeta nuda L. ssp. nuda essential oil rich in nepetalactones from Greece.

Essential oils from air-dried leaves and verticillasters of Nepeta nuda ssp. nuda from Greece were analyzed by means of gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. The dominant constituent in the verticillaster oils was 4aα,7α,7aß-nepetalactone (75.7%). The main metabolites of the leaf oil were 1,8-cineole (16.7%), 4aα,7α,7aß-nepetalactone (24.7%), and caryophyllene oxide (16.3%). The oils were examined for their antioxidant activity. Neutralization of stable 2,2-diphenyl-1-picrylhydrazyl radical ranged from 10.83% (2.50 µg/mL) to 58.64% (50.00 µg/mL) for verticillaster oil and from 6.25% (2.50 µg/mL) to 57.79% (50.00 µg/mL) for leaf oil. The essential oil from verticillasters had significant effects on lipid peroxidation (in the range of 41.18-59.23%), compared to tert-butylated hydroxytoluene (37.04%). In contrast, the essential oil from leaves exhibited pro-oxidant activity at the highest concentration applied.

Comparative analysis of essential oils of six Anthemis taxa from Serbia and Montenegro.

The essential-oil composition of six Anthemis taxa from several populations in Serbia and Montenegro, Anthemis triumfetti (L.) DC., A. tinctoria L., A. austriaca Jacq., A. ruthenica Bieb., A. cotula L., and A. cretica ssp. carpatica (Willd.) Grierson were analyzed by GC and GC/MS. The main constituents have been identified as follows: camphor (13.8-15.4%), alpha-pinene (5.2-9.3%), beta-pinene (4.9-7.8%), and (E)-caryophyllene (7.3-9.8%) in three populations, and cis-chrysanthenol (27.0%) and 1,8-cineole (8.4%) in one population of A. triumfetti; 1,8-cineole (9.0-25.8%) in the oils of five populations, and borneol (16.0%) and spatulenol (16.0%) in the oil of one population of A. tinctoria; cis-chrysanthenyl acetate (17.5-22.0%), beta-pinene (8.6-13.2%), and 1,8-cineole (7.2-10.4%) in the oils of A. austriaca; germacrene D (8.3-11.3%) and terpinen-4-ol (6.3-7.3%) in A. ruthenica oils; beta-cedrene (10.3-19.0%), (E)-beta-farnesene (7.8-13.5%), and germacrene D (5.2-9.1%) in the oils of A. cotula; cis-thujone (39.0%), trans-thujone (13.5%), and yomogi alcohol (7.1%) in the oil of A. cretica ssp. carpatica. The essential oil of A. austriaca was studied for the first time. A cluster analysis based on the relative percentages of all components of the essential oils was used to determine the distances between taxa and populations.

Essential oil from the underground parts of Laserpitium zernyi: potential source of alpha-bisabolol and its antimicrobial activity.

The composition and antimicrobial activity of the essential oil from the underground parts (roots and rhizomes) of Laserpitium zernyi Hayek (Apiaceae) were investigated. The pale blue essential oil, obtained by hydrodistillation, was analyzed by GC and GC-MS. Forty-three compounds were identified (94.3% of total oil). The main constituent, beside alpha-pinene (31.6%) was alpha-bisabolol (30.9%), so this oil may be a novel potential natural source of this sesquiterpene alcohol. The antimicrobial activity was tested using the microdilution method against Gram (+) bacteria (Staphylococcus aureus, S. epidermidis, Micrococcus luteus, Enterococcus faecalis), Gram (-) bacteria (Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli), and two strains of yeast (Candida albicans). L. zernyi oil showed significant antibacterial activity against S. epidermidis, S. aureus and M. luteus, but lower activities against the other tested strains.

Volatile constituents of different parts of Smyrnium olusatrum from Greece.

The essential oils from stems, leaves, inflorescences, and both unripe and ripe infructescences of Smyrnium olusatrum L. (Umbelliferae) collected in Greece were obtained by hydrodistillation and analyzed by GC-FID and GC-MS. Fifty-eight components were identified. Among the samples analyzed, the differences observed were mainly quantitative. All oils were characterized by the abundance of sesquiterpenes. The major components of the stem and leaf oils were furanoeremophil-1-one (54.3% and 28.7%, respectively) and curzerene (18.8%, 29.0%). The main constituents of the inflorescence oil were curzerene (38.1%), germacrone (20.2%) and furanoeremophil-1-one (20.0%), while those of the unripe and ripe infructescence oils were 1beta-acetoxy-furanoeudesm-4(15)-ene (22.1%, 30.8%) and curzerene (29.7%, 17.4%).

Essential oil composition and enantiomeric distribution of fenchone and camphor of Lavandula cariensis and L. stoechas subsp. stoechas grown in Greece.

The essential oils from leaves and inflorescences of L. cariensis Boiss. and L. stoechas L. subsp. stoechas collected in Greece were analyzed by GC and GC/MS. In the inflorescences and leaves essential oils of L. cariensis the most abundant metabolite was camphor (51.8, 48.8% respectively), whereas in the essential oils of L. stoechas subsp. stoechas, the main constituents were fenchone (39.9, 21.0% respectively) and camphor (24.2, 26.3% respectively). Both enantiomers of camphor were present, whereas only (+) fenchone was detected.

Chemical composition of the essential oil of Achillea umbellata growing in Greece.

The essential oil of the aerial parts of the endemic Achillea umbellata (Compositae) was obtained by hydrodistillation and analysed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). Sixty-six constituents were identified. The major constituents of the oil were beta-thujone (62.8%) and camphor (8.7%).

Parnapimarol and nepetaparnone from Nepeta parnassica.

Parnapimarol (1), a new pimarane diterpene, along with nepetaparnone (2) and nepetanudone (3), one new and one previously reported nepetalactone dimer, respectively, were isolated from the dichloromethane extract of the aerial parts of Nepeta parnassica, collected on Mt. Parnassos, Greece. The structures and relative configurations of 1-3 were determined on the basis of their spectroscopic characteristics (1D and 2D NMR, IR, MS). The structure of 2 was confirmed by single-crystal X-ray diffraction analysis. The insecticidal activity of 1-3 against ants and mosquito larvae was also evaluated.

Chemical composition and biological activity of Nepeta parnassica oils and isolated nepetalactones.

Essential oils of Nepeta parnassica, collected at different developmental stages, were analyzed by means of GC/MS. From the fifty-five identified constituents in samples A and B, representing 94.8% and 98.7% of the oils respectively, 4a(alpha),7alpha,7alpha(beta)-nepetalactone (22.0%), 1,8-cineole (21.1%), alpha-pinene (9.5%) and 4a(alpha),7,beta,7alpha(beta)-nepetalactone (7.9%) were the major components of sample A (vegetative stage), whereas in sample B (flowering stage) the main contributors were 1,8-cineole (34.6%), 4a(alpha),7alpha,7a(alpha)-nepetalactone (17.3%), alpha-pinene (11.4%) and 4a(alpha),7alpha,7alpha(beta)-nepetalactone (8.9%). The oils were tested on human health important insects such as the Pogonomyrmex sp. ants and the Culex pipiens molestus mosquitoes with promising results on insect repellency/toxicity.

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.

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.

Screening of some Greek aromatic plants for antioxidant activity.

The role of antioxidants in preventing oxygen radical and hydrogen peroxide induced cytotoxicity and tissue damage in various human diseases is increasingly recognized. In this study the in vitro antioxidant activity of the ethanol extracts obtained from 21 aromatic plants belonging to the Lamiaceae family was investigated. Of the extracts tested, those of Salvia ringens, Salvia pomifera, Stachys spruneri, Origanum dictamnus, Phlomis lanata, Ballota pseudodictamnus, Ballota acetabulosa, Teucrium polium, Calamintha glandulosa and Micromeria graeca exhibited the same activity as alpha-tocopherol.

Composition and antifungal activity on soil-borne pathogens of the essential oil of Salvia sclarea from Greece.

The hydrodistilled essential oils of the aerial parts of wild-growing Salvia sclarea originated from two localities in Greece were analyzed by GC-MS. Sixty-six compounds, representing 93.26-98.19% of the oils, were identified. Linalyl acetate (19.75-31.05%), linalool (18.46-30.43%), geranyl acetate (4.45-12.1%), and alpha-terpineol (5.08-7.56%) were the main components. The antifungal activity of the oil of one locality and of the main components, linalyl acetate and linalool, was evaluated in vitro against three soil-borne pathogens.