Study On Extracting Active Componets From Two Kinds Of Natural Plants With Supercritical CO₂

When the movement of "back to nature" comes into its own in the world, there has been a growing interest in extraction of active components from natural plants with novel technology. This thesis mainly investigated two kinds of processes for extracting active components from Nelumbo nucifera and from rosemary respectively with supercritical carbon dioxide.In the first part, supercritical fluid extraction (SFE) of three alkaloids (Lensinine, isolienine and neferine) from Nelumbo nucifera were studied. These alkaloids, especially the Lensinine, can be used for treatment of heart and blood vessel diseases, and are intended to be used as main components of a new Chinese traditional medicine.Based on the previous work done in our lab, supercritical CO2 extraction was applied to remove some impurities from raw material. Then the influences of the concentration of co-solvent and different alkalis on extraction of alkaloids were investigated. It was found that the possibility of extraction of the alkaloids of Nelumbo nucifera up to the level of 60% in the extracts was limited with supercritical CO2 in the presence of alkali and/or co-solvent, although addition of them could enhance the content of alkaloids extracted greatly. Additionally, several new methods were experimented aiming at the disadvantages of primary purification method existed in the literatures. It was found that the extraction yield of 1.57% and the content of total alkaloids (74.14%) were obtained by calefaction method. The extraction yield of 1.76% and the content of total alkaloids (77.63%) were also obtained by adsorption method. The above experimental results indicated that both adsorption method and calefaction method were better than either literature method for purifying the alkaloids of Nelumbo nucifera, as the specified targets of the extracted and purified products, including extraction yield of 1.0% and the content of total alkaloids of 60% , have reached and over passed. At the same time, the process was simplified and the use of deleterious solvent was reduced. In the second part, extracting active components from rosemary were studied with supercritical CO2. The active components are intended to be used as the raw materials of an air antiseptic. The effects of pressure and temperature on extraction yield were investigated. It was found that the effect of pressure on extraction efficiencies was greater than that of temperature to the extent of experiment. And the optimum extraction temperature of 40℃ and pressure of 35MPa were established. Under above suitable conditions the extraction yield reached 6.38%. Besides, a multiple nonlinear mathematical model was made with the extraction efficiency as objective and the temperature and pressure for the extraction as variables. The Calculated results of mathematic model were tally with experimental results approximately.