Volatile-oils composition, and bioactivity of the essential oils of Plectranthus barbatus, P. neochilus, and P. ornatus grown in Portugal.

Volatile-oils chemical composition and bioactivity of the essentail oils from Plectranthus barbatus, P. neochilus, and P. ornatus (Lamiaceae) were assessed. Aerial parts from these three related Plectranthus species were collected from cultivated plants grown in Portugal, during vegetative and flowering phases. Volatiles, isolated by distillation-extraction, were analyzed by GC and GC/MS. Monoterpene hydrocarbons (12-74%) and sesquiterpene hydrocarbons (4-45%) constituted the main fractions in all volatiles. α-Pinene (3; 12-67%), oct-1-en-3-ol (6; traces-28%), ß-pinene (7; 0.1-22%), and ß-caryophyllene (50; 7-12%) dominated P. barbatus volatiles. P. neochilus major volatile components were α-terpenyl acetate (41; traces-48%), α-thujone (2; 2-28%), ß-caryophyllene (50; 2-28%), ß-pinene (7; 1-25%), and α-pinene (3; 1-19%). Oct-1-en-3-ol (6; 13-31%), ß-pinene (7; 11-24%), α-pinene (3; 11-19%), and ß-caryophyllene (50; traces-11%) were the main constituents from P. ornatus volatiles. These chemical compositions were rather different from those previously found for specimens harvested in Africa and Brazil. Moreover, the volatiles from the flowers are herewith reported for the first time. Essential oils, isolated by hydrodistillation from leaves and stems, showed a yellowish color and unpleasant odor, with yields ranging from 0.08% to 0.84% (v/dry weight). Antioxidant and antimicrobial activities of the essential oils were evaluated by DPPH· and TBARS assays, and agar disc-diffusion method, respectively. Results showed low or moderate antioxidant capacity and significant antimicrobial activity against Gram-positive bacteria.

Intraspecific variability of the essential oil of Cladanthus mixtus from Morocco.

Air-dried aerial parts of wild Cladanthus mixtus were collected from two different regions of Morocco, Bouznika and Oujda, during 2011 and 2012. Forty individual plant samples were hydrodistilled using a Clevenger apparatus and the obtained essential oils were analyzed by GC and GC/MS. The yield obtained varies greatly with a range of 0.3 to 0.8%. The chemical composition of C. mixtus oils changes from one region to another. A total of 53 constituents were identified. To the best of our knowledge, two chemotypes were defined for the first time for this species in the regions studied. 2-Methyl-2-trans-butenyl methacrylate (32.8-35.2%) / ar-curcumene (13-14%) characterize the chemotypeof the C. mixtus plants from Bouznika, and trans-beta-farnesene (35.5-50.3%) the chemotype from Oujda.

Bioassays against pinewood nematode: assessment of a suitable dilution agent and screening for bioactive essential oils.

Acetone was investigated and found to be an appropriate alternative to Triton X-100 as a solvent of essential oils in bioassays aimed to investigate their effects on pinewood nematode (Bursaphelenchus xylophilus) mortality. Therefore it was used as dilution agent to screen the effectiveness of fifty two essential oils against this pest. Thirteen essential oils were highly effective, resulting in more than 90% pinewood nematode mortality at 2 mg/mL, with six of them resulting in 100% mortality. LC100 values ranged between 0.50 mg/mL and 0.83 mg/mL for the essential oils of Origanum vulgare and Satureja montana, respectively. Essential oils were submitted to gas chromatography and gas chromatography-mass spectrometry analysis and their chemical composition established. Data from essential oils with 100% mortality at 2 mg/mL and other essential oils previously found to have LC100 ≤ 2 mg/mL was combined, their chemical profiles investigated by correspondences analysis plus automatic classification.

Volatiles from Thymbra and Thymus species of the western Mediterranean basin, Portugal and Macaronesia.

Thyme is the common name of many taxa belonging to the Thymbra and Thymus genera. Given the economic importance of thyme oils, many thyme species have been studied and their essential oils and other volatile-containing extracts chemically characterized. Thymbra and Thymus species are frequent in the west Mediterranean region, considered to be the centre of origin of the genus Thymus, and extend further westwards in the Iberian Peninsula and northwest Africa, to the Macaronesian region in the Atlantic Ocean. The present work gives an overview of the chemical composition of the volatiles from the taxa of these two genera occurring in the above geographic area.

Foeniculum vulgare essential oils: chemical composition, antioxidant and antimicrobial activities.

The essential oils from Foeniculum vulgare commercial aerial parts and fruits were isolated by hydrodistillation, with different distillation times (30 min, 1 h, 2 h and 3 h), and analyzed by GC and GC-MS. The antioxidant ability was estimated using four distinct methods. Antibacterial activity was determined by the agar diffusion method. Remarkable differences, and worrying from the quality and safety point of view, were detected in the essential oils. trans-Anethole (31-36%), alpha-pinene (14-20%) and limonene (11-13%) were the main components of the essentials oil isolated from F. vulgare dried aerial parts, whereas methyl chavicol (= estragole) (79-88%) was dominant in the fruit oils. With the DPPH method the plant oils showed better antioxidant activity than the fruits oils. With the TBARS method and at higher concentrations, fennel essential oils showed a pro-oxidant activity. None of the oils showed a hydroxyl radical scavenging capacity > 50%, but they showed an ability to inhibit 5-lipoxygenase. The essential oils showed a very low antimicrobial activity. In general, the essential oils isolated during 2 h were as effective, from the biological activity point of view, as those isolated during 3 h.

Menthol and geraniol biotransformation and glycosylation capacity of Levisticum officinale hairy roots.

The biotransformation capacity of Levisticum officinale W.D.J. Koch hairy root cultures was studied by evaluating the effect of the addition of 25 mg/L menthol or geraniol on morphology, growth, and volatiles production. L. officinale hairy root cultures were maintained for 7 weeks in SH medium, in darkness at 24 degrees C and 80 r.p.m., and the substrates were added 15 days after inoculation. Growth was evaluated by measuring fresh and dry weight and by using the dissimilation method. Volatiles composition was analyzed by GC and GC-MS. Hairy roots morphology and growth were not influenced by substrate addition. No new volatiles were detected after menthol addition and, as was also the case with the control cultures, volatiles of these hairy roots were dominated by (Z)-falcarinol (1-45%), N-octanal (3-8%), palmitic acid (3-10%), and (Z)-ligustilide (2-9%). The addition of geraniol induced the production of six new volatiles: nerol/citronellol/neral (traces-15%), alpha-terpineol (0.2-3%), linalool (0.1-1.2%), and geranyl acetate (traces-2%). The relative amounts of the substrates and some of their biotransformation products decreased during the course of the experiment. Following the addition of beta-glycosidase to the remaining distillation water, analysis of the extracted volatiles showed that lovage hairy roots were able to convert both substrates and their biotransformation products into glycosidic forms. GC:gas chromatography GC-MS:gas chromatography-mass spectrometry SH:Schenk and Hildebrandt (1972) culture medium.

Constituents of the essential oil of sea fennel (Crithmum maritimum L.) growing wild in Turkey.

The essential oils isolated by hydrodistillation from freshly obtained aerial parts of sea fennel (Crithmum maritimum L.) were found to be a yellow liquid, obtained in a yield of 0.2% (vol/wt) based on wet weight. The essential oils obtained from young leaves and branches of C. maritimum, collected at two different locations in Turkey (Sipahili and Yesilovacik), were analyzed by gas chromatography-mass spectrometry. Twenty-three components were identified accounting for more than 99% of the total oils. The oils contained mainly monoterpenes, amounting to 89.0% and 99.6%, respectively, of the oils, with gamma-terpinene (36% and 32%), beta-phellandrene (21% and 22%), and sabinene (13% and 9%) as the main components.

Effect of the volatile constituents isolated from Thymus albicans, Th. mastichina, Th. carnosus and Thymbra capitata in sunflower oil.

The composition of essential oils isolated from Thymus albicans and Thymbra capitata collected in Algarve (Portugal), Th. mastichina collected in Algarve and Estremadura (Portugal) and Th. carnosus also collected in Algarve, during the flowering phase, was analysed by gas chromatography (GC) and GC coupled to mass spectrometry (GC-MS). The antioxidant capacity of the oils as well as some of their main components was determined by periodic evaluation of the peroxide values in sunflower oils stored at 60 degrees C. These peroxide values were compared to that of butylated hydroxytoluene (BHT) and control (without adding antioxidants) under the same experimental conditions. The oils of Th. albicans and Th. mastichina, collected in Algarve, were dominated by 1,8-cineole (68% and 45%, respectively), whereas linalool (52%) was the main component from the oils isolated from Th. mastichina collected in Estremadura. Carvacrol (68%) was the major component present in the oils of Thymbra capitata while borneol (18%), terpinen-4-ol (11%) and camphene (9%) were the major ones in the essential oil of Th. carnosus. The essential oils as well as some of their main components showed higher antioxidant capacity than that of the synthetic antioxidant BHT. At the end of the experiment (57 days), BHT showed a percentage of inhibition of 20%, while that of the essential oils ranged from 46% for Th. carnosus, to 59% for Th. mastichina collected in Estremadura.