Study on Extraction Process of Lignans from Fruits of Schisandra chinensis by Supercritical CO_2 Fluid

Objective To study the extraction process of lignans in Schisandra chinensis(Turcz.) Baill.and S.sphenanthera Rehd.et Wils.by supercritical CO2 fluid(SFE-CO2).Methods The orthogonal experimental design was used to optimize the SFE-CO2 conditions including extraction pressure,extraction temperature and flow rate of CO2,which was guided by the extraction rate of total lignans.The contents of four lignans in the extracts of Schisandra chinensis and S.sphenanthera were determined simultaneously by TLC.The SFE-CO2 technology was compared with traditional solvent extraction.Results The optimal SFE-CO2 conditions were as follows: extraction pressure of 25 MPa,extraction temperature of 35 ℃,CO2 flow rate of 2 L/min.The average extraction rates of lignans in Schisandra chinensis and S.sphenanthera were 93.2 % and 95.5 %,with the purity of extracts of 13.0 % and 9.2 %,respectively.The content of γ-schisandrin in the extract of Schisandra chinensis was 2.89 % by SFE-CO2.Conclusion Compared with traditional solvent extraction,SFE-CO2 is a better way for the extraction of lignans from the fruits of Schisandra chinensis and S.sphenanther because of its advantages such as higher extraction rate,higher selectivity,more convenient operation.