本研究主要為分析化妝品常用之二十種精油對於清除DPPH(1,1-diphenyl-2-picrylhydrazyl)自由基、總酚含量與其主要之化學成分之分析。結果顯示二十種試驗樣品中以紅百里香精油(Thymered essential oil)之總酚含量與清除DPPH自由基之能力最為顯著。當樣品濃度10mg/ml時,能清除92.29%之DPPH自由基,半數有效抑制濃度(EC_(50))為1563μg/ml,以氣相層析質譜儀鑑定其主要之化學成分,發現紅百里香精油中含有高比例的百里香酚(Thymol),含量為64.25%。綜合以上之結果,證明精油中酚類化合物的含量與清除DPPH自由基之抗氧化能力成正相關係。
20 kinds of commonly used essential oils were employed to investigate the DPPH (1,1-diphenyl-2- picrylhydrazyl)free radical scavenging ability, total phenolic contents and analysis of the major chemical compositions. The free radical scavenging ability and total phenolic contents of Thyme red is the best in these essential oils. 10mg/ml of Thyme red essential oil was shown 92.29% of the DPPH free radical scavenging ability and its EC_(50) is 1563μg/ml. 64.25% of thymol in Thyme red essential oil was analyzed by GC-MS. It is clear that the amount of the phenol compounds in essential oils and the DPPH free radical scavenging ability is in direct proportion.