Chemical Composition of the Essential Oils of the Iberian Peninsula Endemic Species Eryngium dilatatum Lam.

Eryngium dilatatum Lam. is a thorny Iberian Peninsula endemic species belonging to the Apiaceae family that has not been previously analysed from a chemical point of view. Following our studies on this genus, we characterized the chemical composition of the essential oils from the different parts (inflorescences, stems + leaves, and roots) of this species; these parts were gathered in Cádiz (Spain). The specimens were collected in July during the flowering period and air-dried before the oil extraction by hydro-distillation. The essential oils were analysed by gas chromatography and gas chromatography coupled with mass spectrometry. The different parts of the plant yielded low amounts of pale yellow oil, with the roots being the fraction that provided the lowest amount of oil. The chemical characterization of the essential oils showed qualitative and quantitative differences between the fractions examined, but all of them showed the same principal compound, germacrene D (9.1-46.5%). Similarly, all the fractions shared most of their representative constituents, with their percentage compositions being different from one sample to the other: α-cadinol (3.8%), bicyclogermacrene (3.5%), octanal (3.1%), and spathulenol (2.5%) were found in the inflorescences; octanal (8.1%), α-cadinol (3.7%), δ-cadinene (3.6%), (E)-caryophyllene (2.6%), bicyclogermacrene (2.5%), and spathulenol (2.4%) were found in the stems and leaves; and spathulenol (4.6%), α-cadinol (4.4%), khusinol (3.2%), α-muurolol (3.1%), and δ-cadinene (2.6%) were found in the roots. As far as we know, this is the first report about the chemical composition of this endemic species of the Iberian Peninsula. It contributes to the knowledge of this species and to the genus to which it belongs. This species could be considered as a natural source of germacrene D, which is a sesquiterpene hydrocarbon with active properties.

Optimization of a Green Microwave-Assisted Extraction Method to Obtain Multifunctional Extracts of Mentha sp.

A microwave-assisted extraction (MAE) procedure has been optimized to simultaneously provide multifunctional extracts of Mentha sp. leaves with improved antioxidant properties and, for the first time, with optimal antimicrobial activity. Among the solvents evaluated, water was selected as the extractant in order to develop a green procedure and also for its improved bioactive properties (higher TPC and Staphylococcus aureus inhibition halo). MAE operating conditions were optimized by means of a 3-level factorial experimental design (100 °C, 14.7 min, 1 g of dry leaves/12 mL of water and 1 extraction cycle), and further applied to the extraction of bioactives from 6 different Mentha species. A comparative LC-Q MS and LC-QToF MS analysis of these MAE extracts was carried out for the first time in a single study, allowing the characterization of up to 40 phenolics and the quantitation of the most abundant. Antioxidant, antimicrobial (Staphylococcus aureus, Escherichia coli and Salmonella typhimurium) and antifungal (Candida albicans) activities of MAE extracts depended on the Mentha species considered. In conclusion, the new MAE method developed here is shown as a green and efficient approach to provide multifunctional Mentha sp. extracts with an added value as natural food preservatives.

The Essential Oil Composition of Trachymene incisa Rudge subsp. incisa Rudge from Australia.

Trachymene incisa subsp. incisa is an Australian endemic taxon that varies greatly in the abundance and length of the leaf trichomes. The essential oil composition of five populations of this subspecies, three corresponding to the typical glabrous form and two of the particularly hairy variant, has been analyzed in an attempt to determinate if that variability is also reflected in their composition. The oils have been extracted by hydrodistillation and analyzed by Gas Chromatography (GC) and Gas Chromatography coupled to Mass Spectrometry (GC-MS). The essential oils of T. incisa subsp. incisa were characterized by the high amount of sesquiterpenes that were the major fraction. The sesquiterepene hydrocarbons were significantly higher in the hairy variant in comparison to the glabrous one. According to the main compound, three different chemotypes were found: I.-ß-selinene + bicyclogermacrene and II.-γ-bisabolene + α-pinene for the typical glabrous variant and III.-bicyclogermacrene + ß-caryophyllene for the hairy variant.

Comprehensive phenological description of essential-oil chemotypes of Salvia lavandulifolia Vahl grown under the same environmental conditions.

A comprehensive description of diverse essential-oil chemical profiles was conducted with twelve individual plants of Salvia lavandulifolia Vahl (Spanish sage) gathered from wild populations and grown under identical culture conditions. Whereas the chemical polymorphism within species of aromatic plants is well known, both the statistical significance of the differences in the chemical composition and the setting of chemical profiles have been scarcely studied. Remarkably different essential-oil chemical profiles were described for the wild-growing plants, which remained different during the three years of cultivation, even when acute situations of water stress occurred. Different patterns of representative compounds throughout the phenological cycle of the species were also reported, with 1,8-cineole being the main oil compound described (contents of up to 75.2%). The Mahalanobis distance was used as a separation parameter, to assign a significance level to a single-compound chemotype. The phytochemical heterogeneity of some wild populations of Spanish sage was proved. Furthermore, some concrete genotypes presented high percentages of the following volatile compounds: limonene, 1,8-cineole, trans-caryophyllene, spathulenol, and viridiflorol.

Chemical description and essential oil yield variability of different accessions of Salvia lavandulifolia.

The amount and chemical composition of essential oils are crucial for the modulation of the flavor, scent and therapeutic properties of aromatic and medicinal plants. The aim of this study was to evaluate the effects of phenology and weather conditions on the essential oil yield obtained from the aerial parts of Salvia lavandulifolia Vahl. Besides, we tried to carry out an approach to the chemical composition at the time of full bloom. Essential oil production of several accessions was monitored throughout the whole phenological cycle, both, at the original location growing wild and at the experimental plot as cultivated plants. Local pedoclimatic conditions seem to be crucial for the plant essential oil production. Our results showed high conditioning rates from both yearly climatic conditions and developmental stage of the plants. Maximum yield production was reported at the full seed maturation stage (average 1.74%) and after a slight dry period (average 2.16%). Phytochemical differences were maintained when plants were forced to grow under common pedoclimatic conditions. Thereby, essential oil analysis showed some populations formed by clearly distinct individuals while others had more homogenous plants. Compounds such alpha-pinene, beta-pinene + myrcene, limonene, 1,8-cineol, camphor and beta-caryophyllene were the main compounds of the essential oils of S. lavandulifolia.

Antifungal and antibacterial activity of the essential oil of Chamaecyparis lawsoniana from Spain.

The essential oils extracted from the young stems and leaves of Chamaecyparis lawsoniana (A.Murray) Parl. have been analysed by Gas Chromatography and Gas Chromatography coupled to Mass Spectrometry. A total of 66 compounds were identified representing around the 99% of the total oil. The oil was richer in monoterpenes than in sesquiterpenes. The only main component was limonene with a percentage composition of 77.7%. The rest of compounds that contribute to the fragrance had percentage composition lower that the 3.0%: p-cymen-7-ol (3.0%), myrcene (2.4%), camphor (2.1%), delta-elemene (1.6%), oplopanonyl acetate (1.6%), methyl perillate (1.3%), terpinen-4-ol (1.0%) and beta-oplopenone 1.0%. The antibacterial and antifungal activity of this oil was also tested against different microorganisms. The only fungus tested, Candida albicans, was very sensitive to the treatment with an inhibition halos of 20mm. The oil was more effective with the Gram (+) than with Gram (-) bacteria. The inhibition halos were 12mm, 12-13mm and 12-13mm for Bacillus subtilis, Staphylococcus aureus and Micrococcus luteus respectively. We report new data of the antibacterial and antifungal activity of the essential oil of this species. The essential oil of C. lawsoniana could be considered as a good natural antibacterial and antifungal agent.

Essential oil composition of the different parts of Eryngium aquifolium from Spain.

The essential oils from the different parts [inflorescences (E.a.I), stems + leaves (E.a.SL) and roots (E.a.R)] of E. aquifolium Cav. gathered in Cádiz (Spain), have been extracted by steam distillation and analyzed by gas chromatography and gas chromatography coupled to mass spectrometry. Quantitative and qualitative differences have been found between the analyzed plant parts. A total of 107 compounds have been identified. The main constituents were germacrene D (30.3%) and sesquicineole (26.7%) for E.a.I fraction, germacrene D (46.0%) and myrcene (13.8%) in the E.a.SL, while E.a.R showed phyllocladene isomer (63.6%) as a unique major compound. The percentage composition of the other constituents was lower than 5.5% in all the analyzed fractions. In agreement with other Eryngium species, no specific compound could be used as a marker for the chemotaxonomy of E. aquifolium. However, similarities in volatile composition were found between E. aquifolium and other species growing under similar environmental conditions. As far as we know, this is the first report on the essential oil of this species.

Essential oil composition of three Australian endemic species of Darwinia (Myrtaceae).

The essential oils from the aerial parts of three rare Australian endemic species of Darwinia have been extracted by hydrodistillation and analyzed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). In D. procera, myrtenyl acetate (6.1-29.6%), alpha-pinene (6.9-25.1%), gamma-terpinene (6.2-13.6%), bicyclogermacrene (5.5-10.8%) and (E)-nerolidol (3.4-9.7%) were the principal components detected. D. fascicularis ssp. fascicularis produced an oil in which (E)-nerolidol (33.0%), alpha-pinene (15.1%) and gamma-terpinene (10.2%) were the principal components. In D. peduncularis the major constituents were alpha-pinene (33.5%), gamma-terpinene (23.1%) and bicyclogermacrene (6.7%).

Essential oil composition of two new species of Phebalium (Rutaceae) from north-eastern NSW, Australia.

The composition of the essential oil steam distilled with cohobation from the aerial parts of two new undescribed species of Phelabium, P. stellatum I. Telford & J.J. Bruhl ined. and P. sylvaticum I. Telford & J.J. Bruhl ined., has been analyzed by gas chromatography and gas chromatography coupled to mass spectrometry. Both species were found to have a similar chemical composition. The essential oil of P. stellatum was characterized by high amounts of elemol (24.6-30.8%), beta-phellandrene (5.2-10.8%), beta-eudesmol (6.1-10.0%), hedycaryol (4.5-9.8%), and delta-3-carene (4.4-13.7%). The main compounds of the samples of P. sylvaticum were identified as myrcene (10.6-23.0%), elemol (11.3-14.6%), beta-phellandrene (0.5-14.8%), delta-3-carene (8.0-11.5%), beta-eudesmol (6.7-9.1%), hedycaryol (7.4-9.7%) and alpha-pinene (7.1-8.9%). This is the first report of the volatile components of these two new species.

Chemical composition, antifungal and antibacterial activity of the essential oil of Chamaecyparis nootkatensis from Spain.

The chemical composition of the oil of Chamaecyparis nootkatensis (D. Don) Spach. has been analysed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). A total of 34 compounds were identified representing more than 90% of the total oil. The oil was richer in monoterpenes than in sesquiterpenes, the major constituents being limonene (53.2%), 6-3-carene (21.0%) and a-pinene (12.2%). The antibacterial and antifungal activities of the oil were also tested against Candida albicans, Bacillus subtilis, Enterobacter aerogenes, Enterococcus faecalis, Escherichia coli, Micrococcus luteus, Pseudomonas aeruginosa, Salmonella sp. and Serratia marcescens. Only two of these, Bacillus subtilis and Candida albicans, were sensitive to the treatment, inhibition zones of 11 and 14 mm diameter being obtained, respectively. As far as we know, this is the first report of the antifungal and antibacterial activity of this species.

Essential oil composition of the different parts of Eryngium corniculatum Lam. (Apiaceae) from Spain.

The essential oil from the different parts (inflorescences, stems+leaves and roots) of E. corniculatum Lam. gathered in Guadalajara (Spain) has been extracted by steam distillation and analysed by gas chromatography and gas chromatography coupled to mass spectrometry. Quantitative and qualitative differences have been found between the analysed parts, although all of them contained the same principal compound, 2,4,6-trimethylbenzaldehyde, representing the 50.8%, 50.0%, and 29.8% of the total oil for inflorescences, stems+leaves and roots, respectively. Other representative constituents of the oil were similar in the different fractions: in the inflorescences compounds were found to be alpha-pinene (4.0%), chrysanthenyl acetate (4.0%), 2,4,5-trimethylbenzaldehyde (3.3%), (2Z,6E)-farnesol (2.0%), (E)-nerolidol (2.1%) and (Z)-beta-ocimene (2.1%), while the stems+leaves oil showed 2,4,5-trimethylbenzaldehyde (3.8%), alpha-pinene (3.4%), (E)-nerolidol (2.4%) and (2Z,6E)-farnesol (2.1%), and in the roots oil a phyllocladene isomer (13.0%), (E)-nerolidol (9.4%), beta-eudesmol (4.1%) and (2Z,6E)-farnesol (2.1%) were found. The presence of C-10 compounds as the main fraction for an Eryngium species is worth mentioning. This is the first report on the chemical composition of this Mediterranean endemic species.

Analysis of the essential oil composition from the different parts of Eryngiumglaciale Boiss. from Spain.

The essential oil from the different parts (inflorescences, stems + leaves and roots) of Eryngium glaciale Boiss. gathered in Sierra Nevada (Spain) has been extracted by steam distillation and analysed by gas chromatography and gas chromatography coupled to mass spectrometry. Quantitative but not qualitative differences have been found between the analysed parts. The principal compounds from the inflorescences oil were found to be phyllocladene isomer (43.5%), (E)-caryophyllene (15.2%) and valencene (11.5%), while the oil from stems and leaves only showed phyllocladene isomer (41.3%) as main one. The oil from the roots presented phyllocladene isomer (49.4%) and linalool (19.1%) as major constituents. This is the first report on the chemical composition of this species.

Essential oil composition of the different parts of Eryngium bourgatii Gouan from Spain.

The essential oil extracted from the different parts of Eryngium bourgatii Gouan: stems + leaves (E.b.SL), inflorescences (E.b.I) and roots (E.b.R), have been extracted by steam distillation and analysed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). Quantitative but not qualitative differences have been found between the analysed parts. The principal compounds from the inflorescences oil were found to be phyllocladene (37.6%) and bicyclogermacrene (15.1%), while the oil from stems and leaves showed phyllocladene (20.4%), gamma-muurolene (11.8%) and (E)-caryophyllene (10.1%) as main ones. The oil from the roots presented gamma-muurolene (15.4%) and phyllocladene (15.0%) as major constituents. It is worth mentioning the presence of a diterpene, phyllocladene, as main compound of the essential oil. This is the first report on the essential oil of this species.

Antiherbivore chemistry of Eucalyptus-cues and deterrents for marsupial folivores.

Formylated phloroglucinol compounds (FPCs) are the single most important factor determining the amount of foliage that marsupial folivores eat from individual Eucalyptus trees. Folivores need to recognize which trees contain FPCs if they are to avoid them and forage efficiently, they are challenged by great diversity in the types and quantities of FPCs present, even within eucalypt species. We investigated the relationship between FPCs and terpenoids in species with both simple and complex FPC profiles and found strong positive correlations between terpenes generally, and several monoterpenes in particular, and FPCs. Terpene cues also indicated qualitative differences in trees' FPC profiles. We describe significant qualitative and quantitative variation in FPCs in several species that are important food sources for marsupial folivores. New discoveries include the fact that macrocarpals occur as two major, distinct groups and several new dimeric acylphloroglucinols from Eucalyptus strzeleckii. These patterns add to the chemical complexity of the foraging environment for folivores.

Essential oil composition of the leaves and stems of Meum athamanticum Jacq., from Spain.

The essential oil of the leaves and stems of Meum athamanticum Jacq., has been extracted by steam distillation and analysed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). The monoterpene fraction was predominant while the sesquiterpene one was practically absent. The principal constituents have been identified as (E)-beta-ocimene (29.6%), gamma-terpinene (17.9%), terpinolene (17.0%) and p-cymene (9.7%). Our results show that the chemical composition of the essential oil obtained of the leaves and stems of M. athamanticum from Spain is different to that obtained from plants of Germany, Italy and France.