Extraction Of C₂₁ Steroidal Glycosides From Cynanchum Auriculatum Royle Ex Wight With Supercritical Carbon Dioxide

As a traditional Chinese medicine,it has been reported that Cynanchum auriculatum Royle ex Wight exhibited several potent Phannacological activities,including anti-tumor,antioxidant ability and immunologic enhancement.C₂₁ steroidal glycosides are the characteristic and main effective constituents of Cynanchum auriculatum Royle ex Wight.They are also the symbol constituents to control the quality of the drug.This paper focuses on extraction of C₂₁ steroidal glycosides form Cynanchum auriculatum Royle ex Wight using supercritical carbon dioxide(SC-CO₂) extraction.The main contents of this paper are as follow:(1) In order to establish the quantitative determination method for C₂₁ steroidal glycosides in Cynanchum auriculatum Royle ex Wight,the functional group reaction method of C₂₁ steroidal glycosides quantitative determination was studied in this paper after the research on their extraction method.The sulfonic mercuric reagent method,which was unique to 3-hydrooxyl steroids,was used to determine the C₃-OH on the aglycones directly in order to determine the C₂₁ steroidal glycosides indirectly.The results showed that the method proposed was accurate and sensitive for application to the determination of C₂₁ steroidal glycosides in Cynanchum auriculatum Royle ex Wight. (2) The extractiones of C₂₁ steroidal glycosides from Cynanchum aurieulatum Royle ex Wight with supercritical carbon dioxide extraction were studied.The effect of entrainer extraction systems on the extraction rate of C₂₁ steroidal glycosides is comprehensively evaluated.Among these systems,the efficiency of C₂₁ steroidal glycosides was highest using 95%ethanol as extraction entrainer.Through orthogonal experiment the effects of granularities of material,extraction pressure,extraction time,extraction temperature and the amount of entrainer on extraction efficacy of C₂₁ steroidal glycosides were studied.The results showed that the effects of the five factors were in the sequence of the extraction pressure＞the amount of entrainer＞granularities of material＞extraction temperature＞extraction time.The optimum conditions were:granularities of dry cynanchum bungei 40 item,extraction pressure 35 MPa,extraction temperature 35℃,extraction time 90 min,the amount of entrainer 150 mL.(3) The comparison of supereritical carbon dioxide extraction and organic solvent extraction suggested that the former was more quickly and more secure.The results shew that the supercritical carbon dioxide extraction was a non-toxic and environmental friendly method with higher yield and selectivity.So supercritical carbon dioxide extraction of C₂₁ steroidal glycosides from Cynanchum auriculatum Royle ex Wight was practicable.