Chemical Composition of the Essential Oils of Three Popular Sideritis Species Cultivated in Greece Using GC-MS Analysis.

(1) Background: The essential oils (EOs) of Sideritis L. have attracted great interest due to their pharmacological activities and potential applications in the cosmetic and perfume industries. The aim of this work was to study the EO chemical composition of three of the most popular, in Greece, mountain tea species: namely, these include Sideritis scardica, Sideritis raeseri, and Sideritis syriaca. (2) Methods: The EOs were obtained from the aerial parts of three Sideritis species that were cultivated in various regions of Greece by hydrodistillation, and the chemical composition was studied by gas chromatography-mass spectrometry (GC-MS) analysis. (3) Results: The EOs of the Sideritis species-S. scardica (SSC1, SSC2, SSC3), S. raeseri (SR1, SR2, SR3), and S. syriaca (SS1, SS2, SS3)-were analyzed by GC-MS, and they showed both qualitatively and quantitatively high variation in their chemical composition. (4) Conclusions: The EOs of S. scardica and S. raeseri from three different regions of Greece, and the S. syriaca from three different localities of Crete Island in Southern Greece, showed high chemical variability. Although 165 different components were found to be present in the nine samples through GC-MS analysis, only 7 (1-octen-3-ol, linalool, trans-pinocarveol, p-mentha-1,5-dien-8-ol, α-terpineol, myrtenol, and verbenone) were common components in the nine EOs, which were identified to be highly variable in different percentages among the samples. Even the EOs of SS1 and SS2, which were cultivated nearby, showed different GC profiles. The composition variation observed might be attributed to differentiations in the soil and climatic conditions.

GC-MS, FTIR and Raman spectroscopic analysis of fatty acids of Pistacia vera (Greek variety "Aegina") oils from two consecutive harvest periods and chemometric differentiation of oils quality.

Pistacia vera oil is a rich source of unsaturated fatty acids, whose presence is associated with high quality and nutritional value. According to the literature, fatty acid oil composition is not constant every harvest year, but varies mainly depending on climate conditions. Therefore, the knowledge of oil composition in fatty acids is necessary to assess both its quality and its nutritional value. Twenty-two samples (11 samples from the harvest year 2017 and 11 samples from 2018) of the Greek variety "Aegina" were collected from four different Greek regions, from producers following the same cultivation and post-harvest cares. Extraction oil yields were found to be similar (61.7% w/w, 2017; 60.8% w/w, 2018). A reduction of the saturated fatty acids content was determined in 2018 (mean values 12.2% w/w against 13.8% w/w in 2017) by Gas Chromatography-Mass Spectrometry, accompanied by an increase of the unsaturated ones (mean values 87.9% w/w against 86.2% w/w in 2017). These results indicate that the harvest year 2018 may be considered superior to 2017 in terms of quality and nutritional value and may be correlated with an increased mean rain rate in 2018 and a slight decrease of the mean temperature. Fourier transform infrared (FTIR) and Raman spectroscopic studies of the oils were also performed. Three chemometric models were developed for the two consecutive harvest years of pistachio oil and the discrimination was based on GC-MS analysis, FTIR and Raman spectroscopic data combined with cross-validation techniques and comparison among them. The most successful chemometric model was that based on FTIR spectroscopy, which has the advantage of speed, simplicity and economy. Such a chemometric model may help in estimating the quality of Pistacia vera oils.

Identification of Auxin Metabolites in Brassicaceae by Ultra-Performance Liquid Chromatography Coupled with High-Resolution Mass Spectrometry.

Auxins are signaling molecules involved in multiple stages of plant growth and development. The levels of the most important auxin, indole-3-acetic acid (IAA), are regulated by the formation of amide and ester conjugates with amino acids and sugars. In this work, IAA and IAA amide conjugates with amino acids bearing a free carboxylic group or a methyl ester group, along with some selected IAA metabolites, were studied in positive and negative electrospray ionization (ESI) modes, utilizing high-resolution mass spectrometry (HRMS) as a tool for their structural analysis. HRMS/MS spectra revealed the fragmentation patterns that enable us to identify IAA metabolites in plant extracts from eight vegetables of the Brassicaceae family using a fast and reliable ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QToF-MS) method. The accurate m/z (mass to charge) ratio and abundance of the molecular and fragment ions of the studied compounds in plant extracts matched those obtained from commercially available or synthesized compounds and confirmed the presence of IAA metabolites.