Sensitized Fluorescence And Analytical Methods Of Chlorogenic Acid And Isochlorogenic Acid From Traditional Chinese Medicine

Chlorogenic acid(CA)and isochlorogenic acid(ICA)are important active ingredients of traditional Chinese medicine(TCM),widely found in medicinal plants,with a variety of pharmacological effects.Determination of CA and ICA in TCM samples is of great significance to the quality evaluation of TCM.In this paper,the sensitized fluorescence of CA and three kinds of ICA,including isochlorogenic acid A(ICAA),isochlorogenic acid B(ICAB)and isochlorogenic acid C(ICAC),are studied.On this basis,fluorometric method for the determination of chlorogenic acid and isochlorogenic acids in Chrysanthemum(Juhua)and in Honeysuckle(Jinyinhua)are investigated,and the contents of CA,ICAA and ICAC in Honeysuckle are determined respectively by thin-layer absorption scanning method.The dissertation includes the following three parts:1.The fluorescence properties of CA and three kinds of ICA are studied.The native fluorescence of CA and ICA aqueous solution are very weak.Addition of borax and cetyltrimethylammonium bromide(CTAB)produces relatively strong fluorescence.The fluorescence peak of CA is located at excitation / emission wavelength of 350 nm / 460 nm,ICAA at 350 nm / 480 nm,ICAB at 350 nm / 471 nm,and ICAC at 350 nm / 480 nm.The fluorescence intensity of the four substances is related to the volume fraction of methanol in water solution,the ionic strength,the concentration of borax and CTAB.Under the optimum experimental conditions,the fluorescence quantum yields of CA,ICAA,ICAB and ICAC are measured to be 0.0177,0.0167,0.0154 and 0.0248,respectively.2.Since the fluorescence properties of chlorogenic acid and isoprocarbic acids are very similar,so it is difficult to determine the content of various components without separation.Therefore,the fluorospectrophotometric method and the three-dimensional fluorescence coupled with second-order correction method are used to determine the total amount of CA and ICA in Juhua and in Jinyinhua.The average results of the two methods for the analysis of Juhua are 5.59% and 5.40%,and the average results for the analysis of Jinyinhua are 7.05% and 8.48%,respectively.The results show that the total amount of CA and ICA in Juhua and in Jinyinhhua can be determined by fluorescence analysis,and then can be used for the quality evaluation of the herbs.3.The contents of CA,ICAA and ICAC in Jinyinhua are determined by thin-layer absorption scanning method,the results were 2.76%,1.36% and 0.711%,respectively.Experiments show that the components of Jinyinhua can be completely separated on silica gel plate,and the properties of each component on the plate is stable.The determination precision is good,and the method is simple and easy.