丹酚酸B的水解动力学及降解机理(16页).doc

丹酚酸B的水解动力学及降解机理 郭永学，张华，董悦生，修志龙* 大连理工大学环境与生命学院 生物科学与工程系 大连 116024 摘要：目的 研究丹酚酸B的水解动力学特征和降解机理。方法 运用HPLC定量分析丹酚酸B，运用LC-MS及NMR检测丹酚酸B的水解产物，推测其降解途径。结果 丹酚酸B降解符合一级动力学特征，降解速率随缓冲盐浓度的增加，温度的升高而加快，pH-速率图是 “S”型曲线，在pH2.0时最为稳定。 1H(13C)-NMR鉴定结果表明，丹参素、原儿茶醛、咖啡酸、丹酚酸E、紫草酸和紫草酸异构体Ⅰ等是丹酚酸B的降解产物。结论 得出了丹酚酸B的水解动力学特征，初步推断了丹酚酸B的降解机理。 关键词：丹酚酸B；水解；动力学；降解机理； LC/MS ? 作者简介：郭永学，男，博士生 通讯作者：修志龙，男，博士生导师 Tel：（0411Email：zhlxiu@dlut.edu.cn Hydrolysis Kinetics and Degradation Mechanismof Lithospermic Acid B Guo Yongxue，Zhang Hua，Dong Yuesheng，Xiu Zhilong* Department of Bioscience and Biotechnology,School of Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024,China ABSTRACT: OBJECTIVE To investigate the kinetics and mechanism of degradation of lithospermic acid B (LAB) in aqueous solution. METHODS High performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) were employed. RESULTS The degradation follows pseudo-first-order kinetics under all experimental conditions. The results indicated that the degradation rate increased with the increase of buffer concentration and temperature. The pH-rate profile shows a characteristic S-shape, and the maximum stability was obtained at pH 2.0. Six degradation products including danshensu, protocatechuic aldehyde, caffeic acid, savianolic acid E, lithospermic acid and its isomer I were separated and identified by 1H(13C) NMR analysis. CONCLUSION The characters of kinetics and mechanism of degradation of LAB in aqueous solution were studied. The primary degradation pathway of LAB is proposed. KEY WORDS：Lithospermic acid B; Hydrolysis; Kinetics; Reaction mechanism; LC/MS 丹参是唇形科植物丹参(Salvia miltiorrhiza Bge.)的干燥根及根茎，是味传统中药，具有“袪瘀止痛，活血通经、清心除烦”等功效[1]。丹酚酸B是丹参的主???水溶性成分，含量丰富（占干重的2-8%，约占丹参中总酚酸质量的54%），在抗氧化、清除自由基、保护心脑血管缺血再灌注损伤方面有较强的生物活性[2,3]。图1 丹酚酸B的分子结构（分子式：C36H30O16，分子量：718） Fig. 1 Structure of LAB (M.F. C36H30O16, M.W. 718) 从分子结构上看，丹酚酸B是由两分子丹参素和一个