Effects of Plant Density on the Number of Glandular Trichomes and on Yield and Quality of Essential Oils from Oregano.

Plants yields are influenced by agronomic techniques. Plant density is a complex issue and extremely important when maximizing both crop quality, and biomass and essential oil yields. Plants belonging to the Origanum vulgare subspecies hirtum (Link) Ietswaart were grown adopting four types of plant density and were characterized in biometric and chemical terms. The samples were analyzed using the ANOVA (Principal Component Analysis) statistical method regarding biometric aspects, EO yield and peltate hair density. Essential oil (EO) was extracted by hydrodistillation and analyzed using GC-FID and GC-MS. GC-FID and GC-MS analysis led to the identification of 45 compounds from the EO. Plant density affected production both in terms of biomass and EO. However, it was not found to have affected peltate glandular trichome density or EO quality.

Wild Sicilian rosemary: phytochemical and morphological screening and antioxidant activity evaluation of extracts and essential oils.

To identify the best biotypes, an extensive survey of Sicilian wild rosemary was carried out by collecting 57 samples from various sites, followed by taxonomic characterization from an agronomic perspective. All the biotypes collected were classified as Rosmarinus officinalis L. A cluster analysis based on the morphological characteristics of the plants allowed the division of the biotypes into seven main groups, although the characteristics examined were found to be highly similar and not area-dependent. Moreover, all samples were analyzed for their phytochemical content, applying an extraction protocol to obtain the nonvolatile components and hydrodistillation to collect the essential oils for the volatile components. The extracts were characterized by LC-UV-DAD/ESI-MS, and the essential oils by GC-FID and GC/MS analyses. In the nonvolatile fractions, 18 components were identified, namely, 13 flavones, two organic acids, and three diterpenes. In the volatile fractions, a total of 82 components were found, with as predominant components α-pinene and camphene among the monoterpene hydrocarbons and 1,8-cineole, camphor, borneol, and verbenone among the oxygenated monoterpenes. Cluster analyses were carried out on both phytochemical profiles, allowing the separation of the rosemary samples into different chemical groups. Finally, the total phenol content and the antioxidant activity of the essential oils and extracts were determined with the Folin-Ciocalteu (FC) colorimetric assay, the UV radiation-induced peroxidation in liposomal membranes (UV-IP test), and the scavenging activity of the superoxide radical (O$\rm{{_{2}^{{^\cdot} -}}}$). The present study confirmed that the essential oils and organic extracts of the Sicilian rosemary samples analyzed showed a considerable antioxidant/free radical-scavenging activity.

Study of quantitative and qualitative variations in essential oils of Sicilian Rosmarinus officinalis L.

In this study the chemical characterisation of 10 Sicilian Rosmarinus officinalis L. biotypes essential oils is reported. The main goal of this work was to analyse the relationship between the essential oils yield and the geographical distribution of the species plants. The essential oils were analysed by GC-FID and GC-MS. Hierarchical cluster analysis and principal component analysis statistical methods were used to cluster biotypes according to the essential oils chemical composition. The essential oil yield ranged from 0.8 to 2.3 (v/w). In total 82 compounds have been identified, these represent 96.7-99.9% of the essential oil. The most represented compounds in the essential oils were 1.8-cineole, linalool, α-terpineol, verbenone, α-pinene, limonene, bornyl acetate and terpinolene. The results show that the essential oil yield of the 10 biotypes is affected by the environmental characteristics of the sampling sites while the chemical composition is linked to the genetic characteristics of different biotypes.

Agronomical and chemical characterisation of Thymbra capitata (L.) Cav. biotypes from Sicily, Italy.

In this study, the agronomical and chemical characterisation of 13 Sicilian biotypes of Thymbra capitata (L.) Cav., grown under the same agricultural and environmental condition, are reported. The main morpho-productive parameters and quali-quantitative profile of essential oils (EOs) were determined. The EOs were analysed by gas chromatography-flame ionisation detector and gas chromatography-mass spectrometry. Hierarchical cluster analysis and principal component analysis statistical methods were used to group biotypes according to the EOs chemical composition. The EO yield ranged between 4.6 and 8.1 (v/w). A total of 38 EO compounds have been identified. The compounds mostly represented were α-pinene, myrcene, α-terpinene, p-cymene, γ-terpinene, borneol, carvacrol and ß-caryophyllene. In all biotypes, the carvacrol (67.4-79.5%) was the main compound, confirming that T. capitata is a carvacrol chemotype. The results showed that all Sicilian Thymbra biotypes have a good adaptation to the climatic conditions of the test environment.

Composition and Variability of the Essential Oil of the Flowers of Lavandula stoechas from Various Geographical Sources.

Samples of flowers of wild Lavandula stoechas L. spp. stoechas populations were collected in three areas of Sicily (Italy) and were characterized in agronomic and chemical terms. Essential oil (EO) was extracted by hydrodistillation and analyzed by GC-FID and GC-MS. GC-FID and GC-MS analyses permitted identification of 89 compounds from the EO. The samples were separated into 3 groups using PCA (Principal Component Analysis) statistical method, with reference to the chemical composition of the EO. All three Sicilian populations of lavender were identified as the fenchone chemotype with percentage content ranged between 52.8-71.1%. The population of Partinico showed the highest dry weight of flowers per plant (221.3 g), but the lowest EO yield (0.37%). The essential oils of the three wild Sicilian populations of L. stoechas L. spp. stoechas showed a greater chemical differentiation than those obtained from other Mediterranean areas.