荧光分析法测定喜树果药材中的喜树碱

Fluorimetric analysis of camptothecin in Chinese herbal medicine common Camptotheca fruit

研究了喜树果药材、喜树碱和10-羟基喜树碱的三维荧光图谱和薄层荧光色谱,建立了测定喜树果药材中喜树碱含量的荧光分析方法。在三维荧光图谱中,喜树碱呈现3个荧光峰,激发波长λex分别为215、255和365 nm,发射波长λem均为430 nm;10-羟基喜树碱呈现4个荧光峰,λex分别为220、265、325和375 nm,λem均为555 nm。喜树碱的荧光比10-羟基喜树碱的荧光强。三维荧光图谱对照和薄层荧光色谱分析表明,喜树果药材中的荧光成分主要是喜树碱,10-羟基喜树碱和其他共存组分对喜树碱的荧光基本无干扰。在pH 3.0～6.7条件下,喜树果提取液有稳定的强荧光。以甲醇为溶剂制备喜树果药材提取液,用水适当稀释后于365/430 nm(λex/λem)波长下测定喜树碱的含量。在0.00235～0.235μg.mL 1内,荧光强度与喜树碱浓度之间呈线性关系,回归方程为IF=9+30 844 c,相关系数r=0.999(n=9)。将本法用于喜树果样品中喜树碱含量的测定,结果为0.127%,加标回收率为102%。用薄层荧光扫描法验证了本法的可靠性。结果表明,本法可用于喜树果药材的质量检验。

Three-dimensional（3D） fluorescence spectra and thin layer fluorescence chromatogram of common Camptotheca fruit（CCF） crude drug,camptothecin（CPT） and 10-hydroxycamptothecin（HCPT） have been studied,and a novel fluorimetric method for determination of CPT in CCF crude drug has been established.In 3D fluorescence spectra,CPT presented 3 fluorescence peaks with excitation wavelengths λex of 215,255 and 365 nm,separately,and all peaks with emission wavelength λem of 430 nm.HCPT presented 4 fluorescence peaks with λex of 220,265,325 and 375 nm,separately,and all peaks with λem of 555 nm.The fluorescence of CPT is much stronger than that of HCPT.Comparison of 3D fluorescence spectra and analysis of thin layer fluorescence chromatogram revealed that the main fluorescent component of CCF is CPT.HCPT and other components basically do not interfere with the fluorescence of CPT.Under the condition of pH 3.0？6.7,CCF aqueous solution can produce strong and steady fluorescence.Using methanol as solvent,the extracting solution of CCF was prepared,and diluted properly with water,then measured fluorescence intensity at λex/λem = 365/430 nm to determine the content of CPT.A linear calibration curve covered the concentration range 0.002 35？0.235 μg？mL？1.The regression equation was IF = 9 ＋ 30 844 c,with correlation coefficient r = 0.999（n = 9）.The method has been applied to the analysis of CPT in a CCF sample,with a result of 0.127% and a spiked recovery rate of 102%.The reliability of the method has been verified by a thin layer chromatography-fluorescence scanning method.Experimental results demonstrated that this method can be used for quality evaluation of CCF crude drug.