牛蒡苷与牛蒡苷元的荧光性质及中药牛蒡子中牛蒡苷的荧光法测定

Fluorescent Properties of Arctiin and Arctigenin and Fluorimetric Analysis of Arctiin in Traditional Chinese Medicine Arctii Fructus

牛蒡苷和牛蒡苷元的三维荧光图谱中均呈现2个荧光峰，激发波长λex分别为230nm和280nm，发射波长（λem）均为310nm。牛蒡苷的荧光远强于牛蒡苷元的荧光。溶液酸度对牛蒡苷和牛蒡苷元的荧光强度有明显影响。在pH〉13．0时，牛蒡苷的荧光增强，而牛蒡苷元的荧光猝灭。牛蒡子药材的三维荧光图谱和薄层荧光色谱表明，牛蒡子的荧光成分主要为牛蒡苷，而牛蒡苷元及其他共存组分在强碱性条件下对牛蒡苷的荧光无影响。据此，以甲醇为溶剂制备牛蒡子样品提取液，用水适当稀释并调节至pH13．0，在λex／λem=280nm／310nm波长下测定牛蒡苷的含量。在0．0145～2．03mg·L-1范围内，荧光强度与牛蒡苷浓度问呈良好线性，其线性方程为I-F=2．7＋148．7p（mg·L-1），相关系数（r）为0．999。用本法测得牛蒡子对照药材中牛蒡苷的含量为6．01％，平均加标回收率为98．1％。用薄层荧光扫描法对本方法进行验证，结果表明，本法结果可靠，可用于牛蒡子药材的质量检验。

In three-dimensional（3D） fluorescence spectra, both arctiin and arctigenin presented two fluorescence peaks with excitation wavelengths （λex） of 230 nm and 280 nm, separately, and all peaks with emission wavelength （λem） of 310 nm. The fluorescence intensity of arctiin was much stronger than that of arctigenin. Acidity possesses great influence on fluorescence intensities of arctiin and arctigenin. When pH was larger than 13.0, the fluorescence of arctiin was enhanced, but the fluorescence of arctigenin was quenched. The 3D fluorescence spectrum and the thin layer fluores- cence chromatogram of Arctii Fructus（AF） crude drugs revealed that the fluorescent component of AF was mainly arctiin, whereas arctigenin and other components had no interference with the fluores- cence of arctiin in strong alkaline condition. Accordingly, methanol was used as solvent to extract arctiin from AF sample, and the extraction solution was diluted properly with water and adjusted to pH 13.0. Then, the content of arctiin was determined at wavelengths of λex/λemequal to 280 nm/ 310 rim. The calibration curve for arctiin was linear in the concentration range of O. 014 5 -2.03 mg · L-1, the regression equation was IF = 2.7 ＋ 148.7p （mg · L-1）, with correlation coefficient（r） of O. 999. The method was applied in the analysis of arctiin in an AF control medicinal materials, with a content of 6. 01% and a spiked recovery of 98. 1%. The method was verified by a thin layer chro- matography -fluorescence scanning method, and the results demonstrated that this method was relia- ble, and could be used for the quality evaluation of AF crude drugs.