Essential-oil composition of Zygophyllum fabago aerial parts from Turkey

Abstract

There are many reports in the literature, related to the essential oil of Zygophyllum species (Zygophyllaceae), but several reports describe the antioxidant activity of this genus. Previously, sesquiterpene hydrocarbons and diterpenoids were reported from Zygophyllum fabago L. as the main components [1]. Current research aims to provide information on the essential-oil composition of Z. fabago collected from Ankara, Turkey. The essential oil was obtained by hydrodistillation from air-dried aerial parts of the plant with a Clevenger apparatus for 3 h. The essential oil yield of the plant was in trace amount. The oil was recovered with n-hexane (1 mL) and dried over anhydrous Na₂SO₄. The essential oil was analyzed without further dilution and used in the GC-MS analysis. The essential oil was analyzed with an Agilent 5977 MSD GC-MS system operating in EI mode; injector and MS transfer line temperatures were set at 250 °C. Splitless injection was used in the analysis. Innowax FSC column (60 m x 0.25 mm, 0.25 µm film thickness) and helium as the carrier gas (1 mL/min) were used in GC-MS analyses. The oven temperature program was: 60 °C for 10 min and then raised to 220 °C at a rate of 4 °C/min, afterwards the temperature was kept constant at 220 °C for 10 min and then raised to 240 °C at a rate of
1 °C/min. Mass spectra were recorded at 70 eV with the mass range m/z 35-425. Relative amounts of the separated compounds were calculated from the integration of the peaks in MS chromatograms. Identification of essential-oil components was carried out by comparison of their retention indices (RI), relative to a series of n-alkanes (C₅ to C₃₀), with the literature values, as well as by mass spectral comparison. The aerial parts essential oil of Z. fabago yielded an essential oil rich in oxygenated monoterpenes and diterpenes. The major components of the essential oil were: (E)-phytol (11.7%), (E)-β-damascenone (10.1%), farnesyl acetone C (5.1%), dihydromethylionone (3.9%), (E)-geranyl acetone (3.7%), g-decalactone (3.6%), (E)-β-ionone (3.3%), pentacosane (3.4%), hexahydrofarensyl acetone (2.5%), and hentriacontane (2.8%).