Extraction And Separation Of Isoflavones From Stem Of Pueraria Lobata (Willd.) Ohwi

Isoflavones from stem of Pueraria lobata (Willd.) Ohwi have significant pharmaccutical value. The factors influencing on the extraction and separation process were investigated and the mathematical models for the conventional extraction and the ultrasonically enhance extraction were built. On the above basis, the ways to get daidzein and puerarin were otained and the distribution of puerarin by means of cloud point extraction was investigated.The main contents of this dissertaion are as follows(1) The conventional extraction was stuided using ethanol aqueous solution and n-butanol/water two-phase system as solvents. The effects of extraction time, extraction temperature and solvent composition on the yield of total-isoflavones were investigated. By the assumption of the exponential distribution for the cell energy barriers and with the Fick diffusion law, the mathematical model of conventional extraction was built. The relationship between the yield of total-isoflavones with the extraction time and extraction temperature was expressed quantatively. It was found that the correlation results of the model were in agreement with the experimental data.(2) The ultrasonically enhanced extraction was also stuided using ethanol aqueous solution and n-butanol/water two-phase system as solvents. The effects of extraction time, electrical power input and solvent composition on the yield of total-isoflavones were investigated. The mathematical model of ultrasonically enhanced extraction was built. The relationship between the yield of total-isoflavones with the extraction time and electrical power input was expressed quantatively. It was found that the correlation results of the model were in agreement with the experimental data.(3) The process to obtain daidzein using n-butanol/water two-phase solvent system as a solvent was studied. The effect of electrical power input on the yield of daidzeinwas investigated. The result shows that higher yield of dadizein can be obtained by the integration of solid-liquid extraction and liquid-liquid extraction compared to the conventional process.(4) The effects of pH and puerarin initial concentration on the extraction and stripping efficiency were investigated and the conditions to separate puerarin from the water phase extract were optimized. For cloud point extraction of puerarin, the effects of temperature, concentration of surfactant and salt concentration on the phase ratio(R), distribution coefficent of puerarin (K) and extraction efficiency (E) were studied. Finally, several suggestions were raised to further study on extraction andseparation of isoflavones.