Extraction of phytoecdysones with ethanol-modified supercritical CO2

Biologically active polar substance 20-hydroxyecdysone was extracted from roots and leaves of Leuzea carthamoides with ethanol-modified dense carbon dioxide. The effect of operating conditions (pressure 20-27 MPa, temperature 40-60 oC, ethanol concentration in the solvent 4.3-7.1 wt.%, and solvent-to-feed ratio up to 100 g/g) on the extraction rate and the concentration in extract was examined. The maximum extraction yields were achieved with 7.1 wt. % ethanol in the solvent. Despite the high solvent-to-feed ratios the extraction was not complete; the maximum yield of 20hydroxyecdysone from the leaves containing 1.50 mg/g dry mass was only 0.19 mg/g and the maximum yield from the roots containing 0.49 mg/g dry mass was 0.30 mg/g. The maximum concentration of 20-hydroxyecdysone in CO2 extract from the roots, 2.9 wt.%, was higher than in the extracts obtained with 95% EtOH (1.74 wt.%).