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Introduction: Hirsutine and hirsuteine are the main pharmacological activity ingredients of Uncaria rhynchophylla (UR), playing an important role in treating mental and cardiovascular diseases, such as Alzheimer's disease, hypertension, Parkinson's disease, potential anti-cancer activities and so on., Objective: To develop a cyclodextrin-modified micellar electrokinetic capillary chromatography (CD-MEKC) method for the simultaneous separation and determination of hirsutine and hirsuteine from UR and its formulations., Methodology: The optimal method was developed by investigating influences of significant factors on the separation, and this method was successfully applied for the determination of hirsutine and hirsuteine in UR and its formulations., Results: The optimal background electrolyte (BGE) consisted of 40 mM sodium dihydrogen phosphate (pH 7.0), 150 mM 2,6-dimethyl-β-cyclodextrin (DM-β-CD), 3 mM mono-(6-ethylenediamine-6-deoxy)-β-cyclodextrin (ED-β-CD), and 30 mM sodium cholate (SC). Under these conditions, hirsutine and hirsuteine were successfully separated within 13 min at the separation voltage of 15 kV, temperature of 25°C and the detection wavelength of 224 nm. For the analytes, linear calibration curves were performed within the range 5.0-160.0 μg/mL. The limit of detection (LOD, S/N = 3) and the limit of quantitation (LOQ, S/N = 10) were 0.41, 1.42 μg/mL for hirsutine and 0.60, 2.17 μg/mL for hirsuteine, respectively. The recoveries of three samples were from 97.9% to 102.3%., Conclusion: The method was successfully applied to the determination of hirsutine and hirsuteine in UR and its formulations. Meanwhile, it provides an effective reference of the quality control of UR and its formulations., (© 2019 John Wiley & Sons, Ltd.)

Large-volume sample stacking (LVSS) is commonly used as an effective online preconcentration method in capillary zone electrophoresis (CZE). In this paper, the method LVSS combined with CZE has been proposed to analyze camptothecin alkaloids. Optimum separation can be achieved in the following conditions: pH 9.0; 25mm borate buffer containing 20 mm sulfobutylether-β-cyclodextrin and 20 mm ionic liquid 1-ethyl-3-methyllimidazole l-lactate; applied voltage 20 kV; and capillary temperature 25 °C. The LVSS was optimized as hydrodynamic injection 4 s at 5.0 psi and the polarity switching time was 0.17 min. Under the above conditions, the analytes could be separated completely in <20 min and the detector response was increased compared with conventional hydrodynamic injection. The limits of detection were between 0.20 and 0.78 μg/L. A good linearity was obtained with correlation coefficients from 0.9991 to 0.9997. The recoveries ranged from 97.72 to 103.2% and the results demonstrated excellent accuracy. In terms of the migration time and peak area, the experiment was reproducible. The experimental results indicated that baseline separation can be obtained and this method is suitable for the quantitative determination of camptothecin alkaloids in real samples., (Copyright © 2017 John Wiley & Sons, Ltd.)

A non-aqueous capillary electrophoresis method has been developed for the separation and simultaneous determination of fraxin, esculin and esculetin in Cortex fraxini and its preparation for the first time. Optimum separation of the analytes was obtained on a 47 cm x 75 microm i.d. fused-silica capillary using a non-aqueous buffer system of 60 mM sodium cholate, 20 mM ammonium acetate, 20% acetonitrile and 3% acetic acid at 20 kV and 292 K, respectively. The relative standard deviations (RSDs) of the migration times and the peak heights of the three analytes were in the range of 0.23-0.28 and 2.12-2.60%, respectively. Detection limits of fraxin, esculin and esculetin were 0.1557, 0.4073 and 0.5382 microg/mL, respectively. In the tested concentration range, good linear relationships (correlation coefficients 0.9995 for fraxin, 0.9999 for esculin and 0.9992 for esculetin) between peak heights and concentrations of the analytes were observed. This method has been successfully applied to simultaneous determination of the three bioactive components with the recoveries from 90.2 to 109.2% in the five samples.

A simple and sensitive non-aqueous capillary electrophoresis method has been developed for simultaneous assay of three bioactive components (puerarin, daidzein and wogonin) in three traditional medicinal preparations for the first time. Optimum separation of the analytes was obtained on a 47 cm x 75 microm i.d. capillary using a non-aqueous buffer system of 20% acetonitrile, 25 mm ammonium acetate and apparent pH 9.00, with applied voltage and capillary temperature of 20 kV and 16 degrees C, respectively. The relative standard deviations (RSDs) of the migration times and the peak areas of the three analytes were in the ranges 2.5--4.0% and 3.2--3.9%, respectively. Detection limits of puerarin, daidzein and wogonin were 0.090, 0.145 and 0.090 microg mL(-1), respectively. In the tested concentration range, good linear relationships (correlation coef fi cients: 0.9998 for puerarin, 0.9998 for daidzein and 0.9978 for wogonin) between peak areas and concentrations of the analytes were observed. This method has been successfully applied to simultaneous determination of the three bioactive components with recoveries from 91.0 to 114.0%., ((c) 2004 John Wiley & Sons, Ltd.)