Chemical composition of the essential oil and supercritical CO2 extracts of Zataria multiflora Boiss

Essential oil of Zataria multiflora Boiss, cultivated in Iran, was isolated by steam distillation and compared with supercritical fluid CO2 extracts. The oils and extracts were analyzed by capillary gas chromatography, using flame ionization and mass spectrometric detection. Different parameters, such as temperature, pressure, extraction period (dynamic) and modifier (methanol) concentration were employed to maximize the SFE efficiency. The results showed that, under optimum conditions (P=30.4 MPa, T=55 °C, tdynamic=20 min and Vmodifier=0 μl) extraction of Z. multiflora Boiss was more efficient. Chemical analysis revealed that components extracted under different SFE conditions possessed widely different percentages of constituents [thymol (14.2–67.6%), λ-terpinene (0.1–19.5%) and ρ-cymene (3.6–12.0%)]. The amounts, of co-extracted cuticular waxes varied too. Oil obtained by steam distillation was also compared to the SFE extracts. The results showed that the major components of Z. multiflora Boiss were thymol (44.6%), λ-terpinene (21.5%) and ρ-cymene (13.7%), based on steam distillation.