Supercritical carbon dioxide extraction was used for the extraction of Parrotia persica yellow and amber leaves. The lipophilic phytochemicals present in the analyzed leaves were as follows: neophytadiene, hexahydrofarnesyl acetone, octadecanal, 1-octadecanol, phytol, squalene and α-tocopherol. α-cadinol was present in yellow and β-sitosterol in amber leaves. The Box-Behnken design was used for the optimization of pressure, temperature and CO2 flow rate and response surface methodology for the total extraction yield and α-tocopherol relative amount. The total extraction yield was 1.62% for yellow and 1.52% for amber leaves. The α-tocopherol relative amount was 80.03 mg per 100 g of dry plant material for yellow leaves and 315.30 mg per 100 g of dry plant material for amber leaves. The effects of temperature and CO2 flow rate were found to have a significant influence on the total extraction yield for both plant materials analyzed. The effects of pressure and temperature significantly influenced the α-tocopherol relative amount in both plant materials used. The optimum extraction conditions for the total extraction yield were 30 MPa, 40 °C and 3 kg·h-1 CO2 flow rate for both plant samples. In the case of the α-tocopherol relative amount, the optimum temperature was 40 °C, while the pressure and CO2 flow rate were slightly different. The predicted values matched well with the experimental values for the total extraction yield and α-tocopherol relative amount in all plant materials used for the experiment.
Keywords: Parrotia persica; SC CO2; leaves; α-tocopherol.