Experimental Study On The Purification Of Oridonin By Supercritical Fluid Chromatography

Oridonin, which is extracted from Rabdosia rubescens (Hemsl) Hara, is an ent-kaurene diterpenoid compound with medical uses. Oridonin has medical values such as to remove heatiness and toxin, and act as a painkillers and antiseptic. The major use of Oridonin is to prevent cancer. Plenty of organic solvents is needed in extracting Oridonin through the traditional technology, which is followed by column chromatography and recrystallization to refine it. The technology above, which causes environmental contamination, consume a large quantity of organic solvents and is time consuming besides complex operation.This paper focuses on the extraction and purification of Oridonin by using supercritical fluid technology, which can avoid the aforementioned drawbacks.Firstly, research work was done to obtain the optimum conditions for Supercritical Fluid Extraction. A study on the effects of the yield of Oridonin shows that the use of a 90% ethanol/water mixture as cosolvent is efficiency. On the basis of a series of orthogonal experiments, suitable extraction conditions were obtained: pressure 35 MPa, temperature 328.15 K, flow rate of cosolvent 4 mL/min, flow rate of CO2 25 g/min. According to the experiments results, the extent of effection the efficiency of extraction: flow rate of cosolvent > pressure > temperature > flow rate of CO2. Under the optimum conditions, the yield of Oridonin is 0.402%.Preprocessing preparations, for the Supercritical Fliud Chromatography (SFC) process, were used on the extraction with petroleum ether and ethyl acetate. The separated status, trailing peak and other discrepancy which may occur in the chromatogram has been ameliorated. The content of the collected Oridonin increased from 8.06% to 19.94%.Supercritical Fluid Chromatography is used for the first time in this thesis to purify the extracted Oridonin. Based on experiments of SFC to purify Oridonin, the optimum conditions are as follows: polar cyano coloumn (250 mm×9.4 mm i.d., 5μm), modifier methanol and content 8%(wt.%), flow rate of CO2 18 g/min, temperature 313.15 K, pressure 12 MPa, UV-spectrometer wavelength 238 nm. Under the above conditions, the capacity factor of Oridonin is 7.23, the Resolution of Oridonin and the adjacent peak A is 1.45 and the purity of the collected Oridonin reach 84.4%.On the basis of experimental research, MD method of molecular simulation was used to predict the density of scCO2/CH3OH mixture. Five-parameter mean-field lattice model was used to relate the capacity factor of the Oridonin with temperature and density, resulted in R 2= 0.903 > 0.9, Fc= 7.23>F0.01, which imples that the model can precisely describe SFC process with scCO2/CH3OH as mobile phase. The relation ship of SFC capacity factor of the Oridonin with temperature and density is given as follows:...