Identification and determination of aesculin and aesculetin in ash barks by capillary zone electrophoresis

Summary A capillary zone electrophoresis method for identification and determination of aesculin and aesculetin has been established using borate-phosphate buffer containing 30% ethanol with on-column UV detection. A detailed investigation of the influence of changes in borate concentration, pH, applied voltage, temperature and organic modifier was then carried out. For both aesculin and aesculetin, a linear plot of migration time (MT) against borate concentration was obtained, and ln[measured peak area (MA)] and lnMT both gave linear plots against ln(applied voltage) with correlation coefficient r>0.999, which also resulted in a linear correlation between MA and MT (r≥0.9998) under varied voltage. Ethanol as organic modifier to the background electrolytes helped in separating aesculin and aesculetin from other components in ash barks. The reproducibility with relative standard deviation in MT and in normalized peak area(NA) and linearity based on NA against concentration were evaluated. Finally, the method was successfully applied to monitor the quality of different ash barks and to compare the effect of sample preparation on content of bioactive components in ash bark. Results indicate that CZE promises to be applicable to quality control of traditional Chinese medicines containing aesculin and aesculetin.     

钙(Ⅱ)增敏秦皮乙素-CTMAB体系荧光特性的研究

研究了钙 ( ) -秦皮乙素 - CTMAB体系的荧光性质 ,发现 Ca2 +对秦皮乙素 - CTMAB有较强的增敏作用 ,建立了荧光光谱法测定痕量秦皮乙素的新方法。其线性范围为 2 .38× 10 -8— 2 .38× 10 -6mol· L-1;检出限为 1.2× 10 -8mol·L-1;回收率为 91.39%— 10 2 .31% ;相对标准偏差为 3.6 %。     

Isolation and purification of coumarin compounds from Cortex fraxinus by high-speed counter-current chromatography

High-speed counter-current chromatography (HSCCC) was successfully used for the isolation and purification of coumarin compounds from Cortex fraxinus, the Chinese herbal drug. n-Butanol-methanol-0.5% acetic acid (5:1.5:5, v/v) was used as the two-phase solvent system. 14.3 mg of fraxin, 26.5 mg of aesculin, 5.8 mg of fraxetin and 32.4 mg of aesculetin with the purity of 97.6, 99.5, 97.2 and 98.7%, respectively were obtained from 150 mg of crude extracts of C. fraxinus in a single run. The structures of the isolated compounds were identified by 1H NMR and 13C NMR.     

三维荧光光谱法结合交替三线性分解算法同时分辨及定量测定秦皮中的秦皮甲素和秦皮乙素成分

用三维荧光分析结合交替三线性分解算法对秦皮中药成分进行定性定量分析,为直接测定秦皮甲素和秦皮乙素提供了一种快速简洁的方法。相关系数r分别为1．000和0．998。多次测定结果的相对误差分别为2．01％和2．21％。     

虚拟组分-人工神经网络用于中药紫外光度法中多组分的同时测定

采用虚拟组分自修正、自拟合的方法消除了干扰组分的影响,实现了人工神经网络(ANN)-紫外分光光度法不经分离的中药多组分浓度的同时测定。建立了包含训练网络和拟合网络的双网络ANN算法,提高了ANN算法的自学习、自判别能力,使复杂中草药体系多组分浓度预报的准确度大大提高。对21种不同来源的秦皮中秦皮甲素和秦皮乙素的含量进行了预测,预测结果与HPLC法相比较,以相对误差小于10%计,预测准确率大于90%。该法对秦皮甲素和秦皮乙素的测定精密度分别为0.37%,1.5%。     

Rapid Determination of Coumarins in Plants by Capillary Electrophoresis

The goal of this study was to optimize the parameters for capillary electrophoresis to separate and determine aesculin, aesculetin, umbelliferone, and dihydrocoumarin in plant materials. A simple and rapid capillary zone electrophoresis method is reported for this separation that required less than nine minutes. A bare fused silica capillary was employed using 20 mM borax in 5% methanol at pH 10.1 as the background electrolyte with an applied voltage of 30 kV at 27°C. Good linearity and reproducibility were obtained with high correlation coefficients. The analytes were determined by molecular absorption at 194 and 206 nm. Coumarins were determined in Aesculus hippocastanum L., Cichorium intybus L., Melilotus officinalis L., and Juniperus communis L. “Pendula.” The concentrations of aesculin and aesculetin were 3.07 and 6.31 mg g^?1 in Aesculus hippocastanum. In Cichorium intybus, the aesculetin concentration was 2.42 mg g^?1. The dihydrocoumarin concentration was 0.54 mg g^?1 in Melilotus officinalis, and the concentration of umbelliferone was 0.58 mg g^?1 in Juniperus communis “Pendula.”     

在线测定秦皮甲素和秦皮乙素水解反应速率常数的扫集-流动注射-芯片毛细管胶束电动色谱方法

建立了在线测定秦皮甲素和秦皮乙素水解反应速率常数的扫集-流动注射-胶束电动色谱新方法.该方法进样频率为12次/h,可在5 min内完全分离反应体系中的所有组分,30 min即可完成一个温度下的反应速率常数测定.由于该在线测定方法不需要终止水解反应,通过一次连续进样分析得到水解反应过程电泳谱图,从而可以获得水解反应过程中的一些信息.在最佳条件时,用0.1 mol/L KOH为催化剂,测得25,30,35,40和45C时秦皮甲素的水解反应速率常数分别为3.65×10-2/min、5.24× 10-2/min、7.12× 10-2/min、10.5×10-2/min和16.3×10-2/min,活化能为58.57 kJ/mol.用10 mmol/L KOH为催化剂,测得15,20,25,30和35℃时秦皮乙素的水解反应速率常数分别为2.26× 10-2/min,2.85× 10-2/min,3.55× 10-2/min,4.38× 10-2/min和5.29× 10-2/min,活化能为31.55 kJ/mol.     

秦皮甲素、秦皮乙素与血清白蛋白的相互作用

用荧光光谱法研究了中药有效成分秦皮甲素、秦皮乙素与牛血清白蛋白(BSA)、人血清白蛋白(HSA)的相互作用。结果表明：秦皮甲素、秦皮乙素对血清白蛋白的荧光有较强的猝灭作用,其荧光猝灭为单一的静态猝灭过程,其作用机制属能量转移机制。求得不同温度下反应的结合常数K。由反应焓变、熵变确定它们间的结合主要是静电引力。依据非辐射能量转移机理,求出了其结合位置和能量转移效率。