當歸(根)是國人常食用的藥草之一。本研究係探討不同的萃取溶劑對當歸根抗氧化性之影響。研究結果顯示萃取溶劑對當歸根抽出物之產率、總多酚含量和抗氧化性有顯著地影響。以乙醇和水溶劑萃取之抽出率和總多酚含量顯著高於超臨界二氧化碳流體萃取者。在抗氧化性方面，所有抽出物之抗氧化活性均呈現濃度效應。乙醇和水抽出物之清除超氧陰離子自由基能力、還原力和螯合亞鐵離子之能力皆顯著高於超臨界二氧化碳流體萃取抽出物。但是在脂質過氧化作用之抑制能力，超臨界二氧化碳流體萃取抽出物優於乙醇和水抽出物。整體而言，當歸根顯示出良好的抗氧化性，尤其在抑制脂質過氧化作用之能力和清除超氧陰離子自由基之能力。

Dong-gui is one of important traditional Chinese herbs. The objective of this study is to investigate that the effect of extraction solvent on the antioxidant activity of dong-gui (the root of Angelica sinensis). Results showed that extraction solvents, including 95% ethanol, water and supercritical CO2 fluid (SCF), significantly affected the extraction yield, total phenolic content and antioxidant activity of dong-gui. Both extraction yield and total phenolic content by ethanol and water were higher than those by SCF. All extracts exhibited the antioxidant activity in a concentration-dependent manner. Superoxide anion scavenging ability, reducing power and chelating-Fe2+ effect of both ethanol- and water- extracts were obviously higher than those of SCF extract. However, SCF extract had better inhibition of lipid peroxidation than ethanol- and water- extracts. Generally, dong-gui had good antioxidant activity, especially inhibition of lipid peroxidation and scavenging ability of superoxide anion.