【作者】 李辉；

【导师】 姚守拙；

【作者基本信息】 湖南大学 ， 分析化学， 2005， 博士

【摘要】 本工作是在导师所承担的国家自然科学基金项目和湖南省自然科学基金项目资助下作者在攻读博士学位期间所做全部研究工作的总结和概括。本工作以湘西重要植物资源-杜仲为研究对象，以现代新兴样品预处理技术(超声助提技术和微波助提技术)为工具，从杜仲中提取和分离以绿原酸为代表的多酚化合物，研究了各种提取参量对提取效率的影响。另外，本文也研究了分子印迹聚合物的合成、表面键合位点性能测试及其固相萃取在中草药功效成分分离分析中的实际运用。具体而言，主要开展了以下几方面的研究工作：1． 根据超声波可促进植物细胞破碎，加速细胞内容物与溶剂间的传质过程，设计了用常规超声波清洗盆超声助萃取杜仲中绿原酸的研究，并对超声处理条件进行了考察。与不用超声波时相比，超声助萃取具有提取效率高，溶剂用量少等优点。低温萃取可保证植物材料中生物活性成分的稳定性。2． 研究了用聚焦微波助提技术从杜仲中提取绿原酸和京尼平苷酸。采用实验因子设计法对微波助提条件(辐照时间、溶剂用量、微波功率和溶剂组成)进行了优化。结果表明，微波助提法比常规提取技术大大缩短了提取时间，提高了提取效率。该法也具有较高的重现性。3． 扩大了聚焦微波助萃取技术的应用范围，将之应用于从杜仲中提取多酚酸类化合物。考察了微波辐照时间、微波功率，特别是溶剂的组成和用量对这类化合物微波助提效果的影响。研究了单一溶剂(水或直链一元醇)和混合溶剂下的提取效率。直链一元醇中C原子数较少的醇所获提取率较高。甲醇比水的提取效果更好。以甲醇-水-醋酸的混合溶剂进行提取，效果更佳。4． 研究了用原儿茶酸为模板，甲基丙烯酸为功能单体，乙烯基二甲基丙烯酸酯为交联剂，在四氢呋喃溶液中，通过非共价组装合成了原儿茶酸分子印迹聚合物，通过平衡吸附实验和高效液相色谱考察了分子印迹聚合物对模板分子和结构类似物的重键行为。用Scatchard法研究了聚合物中键合位点的类型、分布和能量。分子印迹聚合物对模板分子有很强的吸附能力，呈现出选择性的键合行为。洗脱剂组成对模板分子及其结构类似物在分子印迹聚合物固定相上的保留行为影响较大，流动相速率影响峰的分辨率。5． 以咖啡酸为模板分子，四氢呋喃-异辛烷(2：1，v/v)为致孔剂，用原位合成法制备了咖啡酸印迹聚合物整块固定相。用前沿分析技术测定了不同温度和不同流动相组成下，咖啡酸及其结构相似物在聚合物上的吸附等温超声、微波助萃取及分子印迹技术在中草药活性成分分离分析中的研究与应用 线。分别用Langmuir方程、Bi一Langmuir方程和Freundlieh方程对所获 实验吸附等温线进行拟合，结果表明用Bi一Langmuir方程和FreundliCh 方程拟合效果较好。通过Bi--Langmuir方程拟合的最佳系数，可获得分子 印迹聚合物表面键合位点的类型、能量分布、饱和吸附量和键合常数等。6.研究了用咖啡酸印迹聚合物整块固定相从杜仲叶提取物中在线分离和纯 化绿原酸。考察了致孔剂组成和不同流动相对聚合物柱通透性能的影响， 获得了最佳制备条件。研究了不同流动相组成下柱的洗脱效果和分析物在 柱上的保留行为。测试了不同进样量下色谱分离效果和所获馏分中绿原酸 的纯度。结果表明，用分子印迹聚合物处理过的杜仲叶提取物中绿原酸的 纯度进一步提高。显示了分子印迹聚合物固相萃取分离和纯化植物提取物 中功效成分的可行性。关键词:杜仲;绿原酸;超声助提;微波助提;分子印迹更多还原

【Abstract】 Two novel types of sample pretreatment techniques (ultrasound - and microwave - assisted extraction approaches) have been used for the extraction of polyphenolic compounds, like chlorogenic acid, caffeic acid, and so on, from Eucommia ulmodies Oliv., a precious Traditional Chinese Medicine existed in the west of Hunan province, in this work. The influence of various extraction parameters in each technique on the extraction efficiencies of the tested compounds has been investigated. Additionally, synthesis and chromatographic behavior of the molecularly imprinted polymers have also been studied. Separation and purification of chlorogenic acid from Eucommia olmodies Oliv. leaves extracts by solid phase extraction of caffeic acid imprinted polymer stationary phase monolith prepared by an in-situ polymerization technique was investigated. This work was financially supported from China NSF, China MST and Hunan Provincial Department of Science & Technology.1. Based on the accelerated mass transfer of the endocyte to the extractionsolvent after the plant cells were crashed by ultrasonic wave, an ultrasonic method for the extraction of chlorogenic acid from Eucommia ulmodies Oliv. using simple cleaning bath was designed. The influence of four extraction variables on extraction efficiency of chlorogenic acid was investigated. Results showed that ultrasonically assisted extraction technique could produce a higher extraction efficiency and consumed less solvent compared with the extraction without ultrasound. A lower temperature in the ultrasonic system increased the stability of the extracted compounds. The application of sonication method was shown to be highly efficient in the extraction of chlorogenic acid from Eucommia ulmodies Oliv. compared with classical methods.2. A new focused microwave-assisted solvent extraction method using water assolvent has been developed for leaching geniposidic and chlorogenic acids from Eucommia ulmodies Oliv.. The extraction conditions were optimized using a two indexes orthogonal experimental design and graphical analysis, by varying irradiation time, solvent volume, solvent composition and microwave power. Microwave-assisted extraction approach greatly shortened the extraction time and increased the extraction efficiency of the compounds.The R.S.D. of the extraction process for both geniposidic and chlorogenic acid were satisfactory.3. An open microwave-assisted extraction system was used to extract polyphenolic compounds, like gallic acid, protocatechuic acid, chlorogenic acid and caffeic acid from Eucommia ulmodies Oliv.. The effect of extraction variables, especially, the solvent composition and volume on the recoveries of these polyphenolic compounds was investigated. Methanol, as extractant, produced a higher recovery than pure water. For straight chain alcohol solvents, the smaller the carbon number, the higher the recoveries of these polyphenolic acids. The optimal ratio of methanol: water: glacial acetic acid in the solvent mixture used in microwave-assisted extraction was 2:8:0.3 (v/v) and this solvent could be directly used as the mobile phase in HPLC separation without additional intermittent treatment as reported in literature. The repeatability of extraction method and chromatographic analysis was satisfactory for the analysis of these polyphenolic compounds.4. A non-covalent imprinting approach was applied to synthesize protocatechuicacid (3,4-dihydroxybenzoic acid) imprinted polymers (MIPs) in the polar tetrahydrofuran by using protocatechuic acid as the template, methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EDMA) as cross-linker. By equilibrium adsorption experiments and high performance liquid chromatography (HPLC), the rebinding properties of the MIPs to protocatechuic acid (template) and its analogues were evaluated. The Scatchard analysis method was used for the detection of the types and energy distribution of binding sites in the polymer. The MIP exhibited high adsorption capability更多还原