Studies On The Synthesis And Purification Of One Natural Product: Apigenin

Apigenin (5,7-dihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) is a naturally occurring polyphenolic compound present in a variety of fruits, vegetables, and seeds. It has many biological and pharmacological activities including anti-inflammatory, anti-cancer, anti-microbial, anti-oxidant, and estrogenic effects. It can also prevent cardiovascular diseases. Because of its valuable uses in healthcare, people has focused on its purification from plants resources in recent years. But the research and application of apigenin was limited by the low content in nature. In this case, the study on the synthesis and purification of apigenin is required.In this thesis, apigenin has been synthesized with new method, the orthogonal experiments were taken to optimize the conditions and feed ratio in the reaction. We also studied the solid-liquid equilibrium of the reactant and product.The main contents of this thesis are as following:In the first chapter of this thesis, we summarize the references about our research, physicochemical properties, pharmacological effects, biological sources and synthetic methods of apigenin. The research contents of this thesis were described on this basis.In the second chapter, apigenin was synthesized from naringin through a simple two-step reaction. Moreover, orthogonal experiments were taken to optimize the conditions and feed ratio in the reaction. The intermediate product and end product were obtained and identified by MS and NMR.In the third chapter, the solid-liquid equilibrium of apigenin and apigenin 7-O-rhamnosylglucoside was studied by analytical method. Simple procedure to analyze apigenin and apigenin 7-O-rhamnosylglucoside with high performance liquid chromatography (HPLC) method was set up, respectively. The solubilities of apigenin in seven commonly used solvents and ethanol+water mixed solvents were determined using HPLC at different temperatures. And the solubilities of apigenin 7-O-rhamnosylglucoside in seven solvents and methanol+water mixed solvents were determined, also. In the forth chapter, the two-parameter and the three-parameter equation were used to correlate the experimental data of the solubilities of apigenin and apigenin 7-O-rhamnosylglucoside in different solvent systems and showed satisfactory results.In the last chapter, all of the experimental work was summarized. We have discussed the deficiencies in this thesis and proposed the suggestions in the latter research.