Optimization of process parameters of extraction of lotaustralin from the roots of Rhodiola rosea L using supercritical CO2 plus modifier

Lotaustralin from the root of Rhodiola rosea L was extracted using supercritical carbon dioxide with methanol as modifier. Response surface methodology using Box-Behnken experimental design was utilized to explore parameters for supercritical carbon dioxide extraction. The effects of various values of temperatures (50-70 degrees C), pressures (200-400 bar), and percentages of methanol modifier (80%-100%) on the extraction yields of lotaustralin were evaluated. Extract identification was performed using high-performance liquid chromatography. The experimental data obtained were fitted to second-order polynomial equations and assessed using analysis of variance. The highest yields predicted from the experiments were 2.05 g kg(1) lotaustralin at the optimal values, i.e. temperature 65 degrees C, pressure 316 bar, 88% methanol modifier at a flow rate of 0.4 mL min(1), and dynamic extraction time 90 min.