Extracts of the bark of the common aspen Populus tremula L. were obtained by supercritical (SC) fluid extraction with carbon dioxide at temperatures of 313.15 and 333.15 K and pressures from 15 to 35 MPa. The component composition of the CO2 extract of Populus tremula L. bark was determined by chromatography–mass spectrometry, which identified significant amounts of fatty acids and their esters. It was determined that conventional liquid extraction with petroleum ether is significantly less effective than SC CO2 extraction in terms of the content of steroidal and triterpenoid components of Populus tremula L. bark in the final product.
Yarullin et al. (Mon,) studied this question.