Abstract Antioxidants have become an essential part of preservation technologies and contemporary health care. However, the currently used synthetic antioxidants have various side effects. Therefore, many efforts have been focused on searching natural antioxidants in recent years. Conventionally, separation followed with bioassay program for searching new natural antioxidants is blindest, time-consuming and labor-intensive. Recently, a method combing separation and antioxidative assay was reported, which is a simple and rapid method for on-line detection of antioxidative compounds in complex mixtures. It is suitable for screening new antioxidants from traditional Chinese medicine (TCM). The thesis includes three chapters. Chapter 1 reviewed the development of antioxidation, including oxidation and diseases, antioxidant activity assays in vitro, and natural antioxidants discovery. Chapter 2 described antioxidant activity determination of three essential oils from TCM, i.e. Angelica sinensis, Curcuma longa, Curcuma wenyujin in vitro. The methods included DPPH radical scavenging activity assay, ABTS radical scavenging activity assay and ẞ-carotene bleaching test. Chapter 3 introduced a HPLC-ABTS method for on-line screening antioxidants from the essential oils with antioxidant activity. The effect of the identified compound was confirmed using the three assays mentioned in Chapter 2. The results showed that the essential oils from Angelica sinensis, Curcuma longa, Curcuma wenyujin had antioxidant activity in the three assays. One major active component in essential oils from Angelica sinensis and Curcuma longa was found by HPLC-ABTS on-line detection, respectively. The component in Angelica sinensis oil was identified as coniferyl ferulate by comparing its UV, MS data with those of reference compound. The antioxidant activity of coniferyl ferulate was also confirmed by the three assays mentioned in Chapter 2. The identification of the active component in Curcuma longa oil need further investigated. But no major active component in Curcuma wenyujin oil was detected. In a word, HPLC coupled with ABTS assay is a useful method for screening antioxidants in TCM extract such as essential oil, which is a simple and rapid method. Keywords antioxidant, essential oil, Angelica sinensis, Curcuma longa, Curcuma wenyujin, HPLC, bioassay detection, coniferyl ferulate

澳门大学硕士学位论文 摘要 鉴于抗氧化剂在人类疾病中的预防和治疗作用,以及化学合成抗氧化剂的 毒性和致病性,越来越多的研究者关注于从丰富的中草药资源中寻求高效、低 毒的天然抗氧化剂。天然抗氧化剂的传统分离方法有盲目性或工作量大的缺 点。近几年,出现了色谱分析和抗氧化活性测定联用的技术,在对植物成分进 行分析的同时进行活性的测定。该方法能够快速地从复杂混合物中筛选出抗氧 化活性物质,为中药活性成分的发现提供了很好的途径。本研究通过该方法对 三种中药挥发油进行了研究。 全文共分为三个部分: 第一章为抗氧化研究进展的文献综述,包括体内氧化的机制及氧化与疾病 的关系、体外抗氧化活性测定的方法和天然抗氧化药物的研究进展; 第二章为中药挥发油抗氧化活性的体外测定。采用 DPPH 自由基清除体 系、ABTS 自由基清除体系和 -胡萝卜素漂白试验测定三种中药挥发油(当 归、姜黄、莪术)的抗氧化活性; 第三章为 HPLC-ABTS 联用体系筛选中药挥发油中的抗氧化活性成分及其 结构确认和活性验证,并对HPLC联用活性检测存在的问题进行了探讨。 结果:当归、姜黄和莪术挥发油在DPPH 自由基清除体系、ABTS 自由基 清除体系和β-胡萝卜素漂白试验中均显示有不同程度的抗氧化作用。HPLCABTS 联用体系从当归和姜黄挥发油中各检出一个具有自由基清除作用的成 分,其中当归油中活性成分经紫外光谱、质谱和对照品比较鉴定为阿魏酸松柏 酯,抗氧化作用研究也显示,阿魏酸松柏酯确有明显的抗氧化作用;姜黄挥发 油中活性成分的确认有待进一步研究;我术油未能检出明显的活性成分。 研究表明,HPLC-ABTS 联用体系是从中药提取物中高效筛选抗氧化活性 成分的有效途径;其未能成功应用于莪术油可能与自由基清除和抗氧化作用的 关联和/或中药多成分协同作用的特点有关,值得深入研究。 关键词 抗氧化,挥发油,当归,姜黄,我术,HPLC,生物活性检测,阿魏酸 松柏酯