β phellandrene

Authentic standards of (E)-2-hexenal, p-xylene, α-pinene, β-pinene, trans-isolimonene, β-myrcene, 2-carene, α-phellandrene, 3-carene, α-terpinene, p-cymene, β-phellandrene, (Z)-β-ocimene, (E)-β-ocimene, γ-terpinene, terpinolene, n-nonanal, allo-ocimene, methyl salicylate, β-elemene, (Z)-jasmone, (E)-β-caryophyllene, and α-humulene (>95% purity) were purchased from Sigma-Aldrich (St. Louis, MO, United States). Dichloromethane (99.9% purity) was purchased from Merck (Germany).

The GC-MS analysis of the EOs was carried out on an Agilent 6890 gas chromatograph equipped with a fused silica capillary column HP-5MS (30 m × 0.25 mm film, 5% phenylmethyl-siloxane and 0.25 μm). The EOs were dissolved in n-hexane (2 mg/mL). The injection of 1 μL of each sample was carried out in split mode with a ratio of 1:100; helium was used as the carrier gas at a rate of 1 mL/min. The operative conditions were as follows: temperature of injector 250 °C, temperature of detector 280 °C. The oven temperature varied as follows: 35 °C to 325 °C with a rate of 5 °C/min. The equilibration time was 0.5 min. MS operate in electron impact was at a potential of 70 eV in a scan range from 50–550 m/z. The identification of the components was based on their Kovats retention indices and their comparison with those of the literature [38 ,39 ,40 (link),41 (link)], and their mass spectra with those available in the NIST 02 and Wiley 275 mass spectral libraries [63 ]. The Kovats indices were calculated related to a series of n-alkanes (C8–C30). This identification of some components was confirmed by co-injection with authentic compounds: α-pinene, sabinene, α-phellandrene, α-terpinolene, methyl eugenol and β-phellandrene (purchased from Sigma-Aldrich, Germany). Quantification was electronically recorded from FID area data using ChromCard program, Thermoquest.

Standard pure compounds for co-injection in GC/MS, α-pinene, β-phellandrene, safrole, isosafrole, and piperonal were purchased from Sigma-Aldrich Co. (St. Louis, MO, USA). The separation and identification of the synthesized compounds was carried out by previously performed methods [24 (link),25 (link)].