Optimization of the Extraction Technology of Volatile Oil from Schizonepeta tenuifolia and Forsythia suspensa / 中国药房

ABSTRACT

OBJECTIVE： To establish the method for content determination of volatile oil of Schizonepeta tenuifolia and Forsythia suspensa， and to optimize the extraction technology of the volatile oil. METHODS： The contents of β-pinene and pulegone were determined by GC method. The determination was performed on Hp-5 capillary column. The detector was hydrogen flame ion detector with programmed temperature. The sample size was 0.5 μL， the split ratio was 70 ∶ 1， the carrier gas was nitrogen， the inlet temperature was 250 ℃， the detector temperature was 280 ℃， the air flow rate was 390 mL/min， the hydrogen flow rate was 36 mL/min， the tail flow rate was 15 mL/min， and the nitrogen flow rate was 1 mL/min. Based on single factor test， orthogonal test combined with information entropy method were used to optimize the extraction technology of S. tenuifolia and F. suspensa using soaking time， extraction time， material-liquid ratio and forsythia grain size as factors， with the extraction amount of volatile oil， the content of β-pinene and pulegone and their comprehensive score as indexes.  RESULTS： The linear range of β-pinene and pulegone 1.575-7.875（r＝0.999 9） and 1.892-9.46 μg（r＝0.999 7）， respectively. The limits of quantitation were 0.10 and 0.25 μg； the limits of detection were 0.03 and 0.08 μg； RSDs of precision， stability and reproducibility tests were less than 2％ （n＝6）； the recoveries were 97.77％-100.01％ （RSD＝0.93％，n＝9） and 96.47％-99.00％（RSD＝0.89％， n＝9）. The optimal extraction technology was soaking 2 h， extracting for 6 h， 10-fold water （mL/g）， half a clove of granularity. Under this condition， the extraction amount of volatile oil， the contents of β-pinene and pulegone were 3.6 mL， 1 450.4 mg， 127.6 mg， respectively. RSD were 1.62％， 0.20％， 1.42％. CONCLUSIONS： Established method is simple， accurate and reproducible， and the optimal extraction technology is stable and feasible.