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This study investigated the feasibility of extracting terpene lactones and flavonoids from Ginkgo leaves by using supercritical carbon dioxide, nitrous oxide, and R134a, respectively. A semi-continuous extraction and absorption process was employed to simultaneously collect and dissolve solutes precipitated from supercritical fluids. The extraction conditions were from 24.2 to 31.2MPa and from 333 to 393K. A RP-HPLC system coupled with RI and UV detectors were utilized to individually quantitate the levels of terpene lactones and flavonoid aglycones in the extracts. Our results demonstrated that three dry supercritical fluids, individually at the density of 0.844, 0.828 and 1.131 g/mL, were unable to extract terpene lactones and flavonoids. However, when supercritical fluid extraction with the addition of ethanol, the extracted amount of terpene lactones increased with the density of three supercritical fluids and the mole fraction of ethanol addition. Smaller particle size increased the amount of terpene lactones in SC--(90mol% CO2+10mol% EtOH) extraction and SC-(90mol% CO2+10mol% EtOH) was able to extract more terpene lactones than other two fluids. Finally, when 31.2MPa, 333K and 300L SC-CO2 extracted 90g dry leaves, suspended in 180mL EtOH, the yield of terpene lactones and flavonoids was 91% (i.e. 985μg/g) and 29% (i.e. 1342μg/g) of that extracted by EtOH Soxhlet extraction, respectively. It was found that a tablet, which raw material imported from Germany, contained the highest amounts of terpene lactones and flavonoids amoung four commercialized tablets.
本研究探討半連續式超臨界二氧化碳(SC-CO2)、一氧化二氮(SC-N2O)和四氟乙烷(SC-R134a)，分別萃取銀杏葉中內酯和黃酮類的可行性。萃取壓力範圍24.2~31.2 MPa，溫度範圍為333~393K。高效能液相層析儀的RI和UV偵測器，分別定量分析萃出液中的內酯和黃酮醣苷的水解黃酮醇量。研究結果顯示三種乾超臨界流體分別在密度為0.844、0.828和1.131g/mL時，均無法萃出銀杏葉中的內酯和黃酮。當進一步在三種流體中順序添加10mol%乙醇混合萃取時，數據顯示SC-CO2中的內酯萃出量大於SC-N2O及SC-R134a者，且隨超臨界流體的密度及乙醇添加莫耳分率增大而增加，但黃酮仍少量萃出。當銀杏粉粒徑較小時，質傳效果較佳，使得內酯在SC-CO2中的萃出量較大。最後，在31.2MPa及333K和300公升的SC-CO2萃取已預先添加(Wdry leaf : VEtOH = 1:2) EtOH的銀杏葉時，可得985μg/g的內酯，即等於91%的索式萃出率，但黃酮類的萃出量僅1342μg/g，仍低於4631μg/g的索式萃出量。市售四種銀杏藥劑的分析結果，顯示德國原料台灣產製的每克劑錠中含有較高的銀杏內酯及黃酮類。
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