Study On Fluorescence Spectrum Of Chinese Traditional Herbs Radix Peucedani,Dichroa Febrifuga & Salicylic Acid,Protocatechuic Acid

With a long history, Chinese traditional medicine plays an important role in the fields of medicine not only in China but also in all over the world. With the development of science and technology, the way to modernization and standardization of Chinese traditional medicine is becoming more and more crucial. Furthermore, among all kinds of methods, fluorescence method plays a more and more impotent role in the study of Chinese traditional medicine and its effective components.In this thesis, fluorescence spectra of water extraction and powder of Radix Peucedani and Dichroa febrifuga were studied. Moreover, two familiar organic acids in Chinese traditional medicine were studied by fluorescence method. By means of fluorescence analysis of Chinese traditional medicine and its components, methods for quantitative determination of fluorescent components and qualitative identification of Radix Peucedani and Dichroa febrifuga were proposed. The main contents of the thesis are as follows:1. Fluorescence properties of water extraction and powder of Radix Peucedani were studied. The influence of experimental conditions on fluorescence was investigated. Using quinine bisulphate as a reference, fluorescence quantum yield of Radix Peucedani was measured, and its fluorescence quantum yield was determined to be 0.16.2. Fluorescence spectra of changshan (Dichroa febrifuga Lour) aqueous extraction were studied. In the three-dimensional fluorescence contour spectrum, three fluorescence peaks of quinazoline alkaloids, which are the active components of changshan, were observed. The excitation wavelengths of the peaks were 235 nm, 270 nm and 320 nm, respectively, and the emission wavelength of all the peaks was 430 nm. Three-dimensional fluorescence contour spectrum is the very image of fingerprint, suitable for qualitative identification of traditional Chinese medicine. In the range of pH 3 to pH 6, with the variation in pH value, fluorescence spectrum of changshan aqueous extractions changes. The reason of this spectral change is because of the protonation of N-l in quinazolone ring of β-dichroine (febrifugine) molecule. There is an excellent linear relationship between fluorescence intensity and the concentration of changshan under nearly neutral conditions, thereby a quantitative method for the determination of quinazoline alkaloids may be established.3. Fluorescence spectra of salicylic acid were studied. The influence of acidity and concentration on fluorescence intensity were investigated. Using quinine bisulphate as a reference, fluorescence quantum yield of salicylic acid was determined to be 0.40. The findings show that salicylic acid is a strong fluorescent material.4. Fluorescence spectra and UV absorption spectra of protocatechuic acid were studied. The influence of acidity and concentration on fluorescence and absorption spectra were investigated. Using quinine bisulphate as a reference, fluorescence quantum yield of protocatechuic acid was determined to be 0.02. The ionization constant were measured by UV absorption method, and the ionization constants pK_a1 = 4.50, pK_a2 = 6.93, were determined respectively.