本研究主要以精油常見的26種化學成分，其中包括6種酚類、8種酮類、6種醚類和6種酸類成分，對於DPPH自由基清除能力分析。結果顯示此四種類別之化學物質，清除DPPH自由基能力在酚分類中，最為顯著的是丁香酚（Eugenol），在濃度為100μg/m時，清除率達94.78%，其EC50為0.27μg/ml、酮類則為（S）-（+）-香芹酮（（S）-（+）-carvone），在濃度為50mg/ml時，清除率達92.86%，其EC50為5.22mg/ml、醚類則為丁香酚甲醚（Eugenol methyl ether），在濃度為500mg/ml時，清除率達95.19%，其EC50為1.04mg/ml，而在酸類則是棕櫚酸（Palmitic acid），在濃度為50mg/ml時，清除率達40.64%。本研究將持續進行各類抗氧化力實驗方法與加成實驗，藉此累積精油化學成分其抗氧化能力的資料庫，未來只需運用GC-MS檢測精油的化學成分及成分百分比，即可簡易的估算出精油的抗氧化力。

This study examines the antioxidant activity of 26 basic chemical compounds in essential oils, including 6 types of phenols, 8 of ketones, 6 of ethers, and 6 of acids using DPPH radical scavenging activity. Results showed that among these chemical compounds, the antioxidant activity of eugenol was 94.78%, and the EC50 value was 0.27 μg/ml measuring in 100 μg/ml. The antioxidant activity of (s)-(+)-carvone was 92.86% and the EC50 value was 5.22 mg/ml. For eugenol methyl ether, the antioxidant activity was 95.19% and the EC50 value was 1.04 mg/ml in 500 mg/ml. Among acids, the value of palmitic acid was 40.64% in 50 mg/ml. Therefore, this study indicates that by continually enlarging the database, we can estimate the DPPH radical-scavenging activity of essential oils by using GC-MS to detect the percentage of their composition.