补骨脂素和异补骨脂素与人免疫球蛋白的相互作用

将互为同分异构体的两种植物药活性组分补骨脂素和异补骨脂素作为研究对象, 应用荧光光谱法、紫外光谱法以及红外光谱法并结合分子对接技术对这两种香豆素类化合物与人-γ球蛋白(Human gammago-bulin, HG)的相互作用进行了比较研究. 荧光光谱法研究结果表明, 补骨脂素和异补骨脂素与蛋白之间均有较强的结合(结合常数位于0.251×10⁴～3.503×10⁴之间), 且对HG都表现为静态猝灭. 不同温度(298, 308和318 K)下两种药物与HG相互作用的结合参数均有所差别, 维持药物-蛋白质体系的作用力也不相同. 依据Förster能量转移理论, 得到补骨脂素和异补骨脂素分子与蛋白质色氨酸残基间的结合距离r值(分别为3.65和4.21 nm)都小于7 nm, 说明发生了能量转移. 利用同步荧光与红外光谱法研究了药物对蛋白质二级结构的影响. 分子对接研究结果表明, 这两种药物与蛋白有相似的结合区域和相同的结合模式.     

β-环糊精包合荧光法对异补骨脂素血药浓度的探测

本文用β－环糊精包含荧光法对兔体中异补骨脂素的血药浓度进行了连续监测，达峰时间为1.0955h，血中异补骨脂素的含量在0.27-2.24μg/mL之间，方法简便、快速、效果良好。     

Experimental and Theoretical Study on Pyrolysis of Isopsoralen

The pyrolysis of isopsoralen was studied by synchrotron vacuum ultraviolet photoionization mass spectrometry at low pressure. The pyrolysis products were detected at different photon energies, the ratios of products to precursor were measured at various pyrolysis temperatures. The experimental results demonstrate that the main pyrolysis products are primary CO and sequential CO elimination products (C₁₀H₆O₂ and C₉H₆O). The decomposition channels of isopsoralen were also studied by the density functional theory, then rate constants for competing pathways were calculated by the transition state theory. The dominant decom-position channels of isopsoralen and the molecular structures for corresponding products were identified by combined experimental and theoretical studies.     

Simultaneous determination of psoralen and isopsoralen in plasma and Chinese medicine Xian Ling Gu Bao capsule by using HPLC-DAD coupled with alternating trilinear decomposition algorithm

A method using high performance liquid chromatography with photodiode-array detection (HPLC-DAD) coupled with alternating trilinear decomposition (ATLD) algorithm was proposed for simultaneous determination of psoralen and isopsoralen in plasma and Chinese medicine “Xian Ling Gu Bao” capsule (XLGBC). In this paper, the application of ATLD algorithm into traditional chromatographic method can handle this problem that the chromatographic and spectral peaks are heavily overlapped among the analytes and even between the analytes and interferences from the background matrices. A simple improvement of chromatographic condition like mobile phase is not enough to realize effective separation for the two isomeric compounds, especially in the presence of interferences. However, the ATLD algorithm utilized “mathematical separation” instead of partial “physical or chemical separation” to directly determine the spectral profiles of the analytes of interests in complex system. The satisfactory quantification results have been gained with simple mobile phase. In the analysis of real Chinese medicine samples, the accuracy of the concentrations which were obtained by ATLD was also validated by HPLC-MS method.     

异补骨脂素热解实验和理论研究

利用同步辐射真空紫外光电离质谱技术,在不同光子能量下,研究了异补骨脂素(C₁₁H₆O₃)的低压热解,探测了不同温度下异补骨脂素的热解产物及其与前驱体的比例. 实验结果表明,异补骨脂素的主要热解产物是CO及其依次消去CO的产物(C₁₀H₆O₂和C₉H₆O). 利用密度泛函理论计算异补骨脂素的解离途径,并利用过渡态理论计算了竞争通道的反应速率常数. 通过实验和理论的结合,确定了异补骨脂素主要解离路径和相应产物的分子结构.     

补骨脂素和异补骨脂素键合人血清白蛋白的比较

将互为同分异构体的两种植物药活性组分补骨脂素和异补骨脂素作为研究对象,利用荧光光谱、紫外光谱、圆二色谱及傅立叶变换红外光谱详细比较研究了这两种香豆素类化合物与人血清白蛋白(HSA)的键合作用.不同光谱的结果定性、定量地显示了HSA二级结构变化的程度.依据荧光滴定实验及Van′t Hoff公式求出了反应的热力学参数(ΔH和ΔS)的值.根据修正后的Stern-Volmer和Scatchard方程和荧光光谱数据分别求得不同温度(296,303,310及318 K)下药物与蛋白相互作用的结合常数及结合位点数;且根据F觟rster偶极-偶极能量转移理论,求得药物与HSA间的键合距离;利用竞争实验确定了药物在HSA上的键合位点为site II.从分子水平上揭示了这两种化合物与HSA相互作用的机制.     

荧光法测定补骨脂素和异补骨脂素

以溴代十六烷基三甲胺（ＣＴＭＡＢ）为胶束试剂，β－环糊精（β－ＣＤ）为包含试剂，在优化实验条件下，用荧光光度法测定了补骨脂中补骨脂素和异补骨脂素．线性范围分别为２×１０－９～８×１０－６ｇ／ｍＬ，２×１０－９～８×１０－７ｇ／ｍＬ；检出限分别为２．６７×１０－１１ｇ／ｍＬ和１．１５×１０－１１ｇ／ｍＬ．     

Determination of Psoralen and Isopsoralen in Traditional Chinese Medicines by Capillary Zone Electrophoresis with Amperometric Detection

A simple, reliable and reproducible method was developed for determination of psoralen and isopsoralen in several traditional Chinese medicines, such as Shouwu Pian, Gubenkechuan Pian, was described in this paper. It was based on capillary zone electrophoresis with amperometric detection (CZE-AD). A carbon-disc electrode was used as working electrode. The optimal conditions of separation and detection were pH7.6 phosphate buffer (20 mM), 20 kV for the separation voltage and 1.00V (vs. Ag/AgCl) for the detection potential. The linear ranges were 6.90 × 10^-5~1.30 × 10^-7 mol L^-1for psoralen and 5.0 × 10^-5~1.80 × 10^-7 mol·L^-1 for isopsoralen with the correlation coefficient of 0.9984 and 0.9994, respectively. The detection limits for psoralen and isopsoralen were 4.2 × 10^-8 mol·L^-1 and 6.0 × 10^-8 mol·L^-1 based on the signal to noise ratio of 3. The method built in this paper was directly applied to the determination of several traditional Chinese medicines with some simple pretreatment. The assay result was satisfactory.