Objective To compare the effects of SFE - CO2 extraction and steam- distillation extraction for the extraction of volatile constituents from Huoxiang Zhengqi prescription. Methods The recovery rate of the volatile constituents and GC- MS method were used to compare the two different extraction methods. Result The recovery rate of volatile constituents was 0.45 % when extracted by steam distillation for 5 hours and 2.40 % by SFE - CO2 extraction for 3 hours. A large amount of peaks were detected in the SFE - CO2 extraction, while few compounds could be detected in the steam distillation extract 15 minutes later. Conclusion SFE - CO2 extraction method is a better method for the extraction of volatile constituents from Huoxiang Zhengqi prescription,with higher recovery rate, obtaining more ingredients and costing less time compared with those by steam distillation extract method.

AIM: To establish a method of determining the content of volatility contents in Baicao Oil. METHODS: The content of menthol, cinnamaldehyde, and eugenol were determined by gas chromatography. RESULTS: Menthol, cinnamaldehyde, and eugenol were well separated and the linearity was fine with the recovery in the range of 98%-102%. CONCLUSION: The method is rapid, stable and accurate. It can be used to control the quality of this preparation.