本研究主要以常見之二十三種臨類精油成分對於清除DPPH自由基能力與其作用之分析。結果顯示其中十二種試驗樣品中以乙酸香茅酪(Citronelly1 acetate)之抗氧化力最為顯著，於200 mg/ml時抗氧化力達8l.58 % '其ECso之濃度為133.605mg/ml。另十一種試驗樣品於500 mg/ml 時，以乙酸萃乙酪(2-Phenylethylacetate)之抗氧化力最為顯著，抗氧化力達85.16 % '其ECso濃度為149.42mg/ml '水楊酸萃甲酪(Benzylsalicylate)�;t氧化力達到.95% '其ECso濃度為378.07mg/ml'丙酸松油脂(Terpinyl propionate)�;t氧化力達5l.l0 % '其ECso濃度為488.95mg/ml。依實驗 結果，再進一步以500mg/ml抗氧化力前三名與前五名，以固定比例混合測定，其清除率分別達 預估值的9l.67%與98.15% '其結果顯示不同的精油成分之間，對於清除DPPH自由基的能力有加成的作用。透過不斷的資料庫累積，運用GC-MS檢測精油的化學成分及所含百分比，即可簡易的估算出精油的抗氧化力。

This study was designed to examine the antioxidant effect of the 23 basic chemical compounds from essential oil by utilizing DPPH radical-scavenging activity. Among these 23 chemical compounds, the result showed that the Citronellyl acetate revealed the highest antioxidant effect in terms of DPPH radical-scavenging activity. The value of antioxidant effect was 81.58 % and the EC50 value was 133.605 mg/ml measured at 200 mg/ml. At 500 mg/ml, the antioxidant effect of 2-Phenylethyl acetate was 85.16% with EC50 value at 149.42 mg/ml; Benzyl salicylate has an effect of 54.95 % and value of 378.07 mg/ml while Terpinyl propionate has an effect and value of 51.10 % and 488.95 mg/ml respectively. According to a further study, the value of DPPH radical-scavenging effects of the top 3 and top 5 chemical compounds of essential oils could reach 91.67 % and 98.15 % respectively by proportionally mixing them at 500 mg/ml. Therefore, after continuously establishing the database in the future, we could estimate the DPPH radical-scavenging effect by detecting the percentage of chemical compounds in the essential oils.