| Vaccinium Bracteatum Thunb, a traditional Chinese herbal medicine, is widely grown throughout China, which belongs to the same genus as ericaceae. Some physiological functions of flavones from Vaccinium Bracteatum Thunb Leaves(VBTL) such as antioxidant activity, antimicrobial activity, anticancer, affecting blood glucose and plasma lipid levels have been investigated. The flavones from VBTL has a great potential to be used as clinical therapeutic agents, natural preservatives or health products.According to the present research, the quantitative method was established. Then Ultrasound/Microwave Assisted Extraction(UMAE) was employed to extract flavones from VBTL and the extraction technology was optimized by response surface methodology. To further investigate the process, mathematical model of UMAE process was established. Macroporous resin was used for the preliminary purification of flavones from VBTL in our work, and adsorption kinetics, isotherm and thermodynamics were investigated at the same time. Then a series of purification technologies were employed subsequently, and VBTL4 A was obtained.The main results were listed as follows:1. Conditions for determination of the fluorescence intensity by fluorescence spectrophotometry was as follows: The excitation wavelength and emission wavelength were 434 nm and 484 nm respectively, standing time was 5 min, p H was4.4, volume of Al Cl3(5%) was 1 m L, ethanol concentration was 100%(v:v). The method had good repeatability, high recovery and stability under the detection conditions, which indicated the method was simple, reliable and suitable to determine the content of flavones from VBTL.2. The optimal conditions of UMAE of flavones from VBTL were obtained as follows: 140 W of microwave power, 69 ℃ of temperature, 51(m L/g) of solvent-solid ratio and 11 min of extraction time, respectively. The yield of flavones was 3.64% under the optimal technology. The results of IR spectrum implied UMAE had no influence on the structure of flavones from VBTL. Mathematical model of extraction process was established based on Fick’s second law. Effect of microwave power, temperature and solid-solvent ratio on model and yield of flavones from VBTL was investigated to validate the model established, the results indicated the mathematical model gave a good approximation of experimental data under variousoperating conditions.3. The static adsorption and desorption experiments were performed, NKA-2resin was chosen as packing material. The purification technology was determined as follows: 0.75 mg/m L for sample concentration, 2 bed volume(BV) for loading sample volume, 50%(v:v) ethanol solution for desorption, 1 m L/min for the flow rate of the eluent and 3 BV for the volume of eluent. After purifying by NKA-2 resin, the removal rate of proteins and polysaccharides reached 76.32% and 65.45%respectively. Purity of flavones reached 48.92%. Adsorption kinetics, isotherms and thermodynamics of flavones from VBTL on NKA-2 resin were investigated, the results indicated pseudo first-order model and Freundlich isotherm model were suitable to characterize the adsorption process.4. VBTL4 A was obtained from VBTL crude extracts after purifying by macroporous resin, polyamide and silica gel column. IR, MS and NMR were employed to identify VBTL4 A, results indicated VBTL4 A was 2, 4, 6, 2’, 4’, 6’-6hydroxyl group chalcone. |
