| Semen Orxyli, which is the mature seed of Oroxylum indicum (L.) Vent, has been used a traditional Chinese medicine for its abilities of moistening lung, relieving cough, smoothing liver, eliminating phlegm, promoting new growth of tissues etc. A number of academic studies show that the main chemical components of Oroxylum indicum are Oroxin A, Oroxin B,Tetuin, Baicalin and so on. So far, the research of Oroxylum indicum has mainly focused on the determination, separation and pharmacological actions of the active components.The contents of the active components were determined by using HPLC or RP-HPLC method to test a single component. Only Dian-li Hu has determined the contents of total flavonoids with Baicalin as a chemical reference substance. But the determined of total flavonoids with Oroxin A as a standard and purification of total flavonoids from Oroxylum indicum by macroporous adsorption resins have not been reported. With the development of plant-based drugs, The ethanol extracts from Oroxylum indicum become used more and more in pharmaceutical industry, food industry and other fields, and their qualities are required of higher standard. Based on this, this paper selects Oroxylum indicum as the raw material, obtains Oroxin A and then carries out the structural identification and purity determination, makes the systematical research on the technical conditions of separation and purification total flavonoids from Oroxylum indicum. The main content includes:1. The mature seeds of Oroxylum indicum were first dried,crushed and extracted by 70% ethanol, the extracts after being condensed, alcohol precipitation and centrifugation were separated by silica gel column chromatography. The eventual result is that the Oroxin A was found. Then its structure was identified by 13CNMR and 1HNMR, and the purity of Oroxin A was determined by melting point, UV absorption and RP-HPLC. The result showed that the purity of Oroxin A was 98%.2. The standard working curve is C (μg/mL)=16.7491 A-0.2975, R2= 0.9998,which was obtained by ultraviolet spectrophotometry with home-made Oroxin A as a standard. At the same time, the studying of methodology showed the method was inaccurate, reliable and could be repeated. It could be used to determine total flavonoids of Oroxylum indicum.3. Static adsorption and dynamic adsorption method were combined to study the five different types of macroporous adsorption and desorption properties The results showed that HPD100 resin have good adsorption capacity than other resins. As a result, HPD100 resin was selected to separate and purify the total flavonoids of Oroxylum indicum.4. The purification of the process conditions total flavonoids of Oroxylum indicum attached by HPD100 resin found that when the concentration of the sample is 5.303mg/mL, pH value is 2-3, velocity of flow is 3.0 mL/min,the adsorption rate of the total flavonoids of Oroxylum indicum is relatively big,when the amount of water used is 3 BV,the water-soluble impurities can be basically divisible, using the 90% ethanol as the desorption agent,the amount used is 8BV, the desorption effect of the flavonoids is relatively good. Under such condition, the purity of the total flavonoids of Oroxylum indicum can reach to 88.3% after division and purification with stable process and good reproducibility.5. The kinetic and thermodynamic experimental results of studying HPD100 resin’s adsorption of Oroxylum total flavonoids show that the process basically reaches equilibrium at 150 min, and its kinetics follows the pseudo-second-order kinetic model. Besides, Freundlich isotherm adsorption equation is more suitable for the whole process, and the enthalpy change AH in adsorption process is negative and its modulus is less than 40KJ/mol. The adsorption process is an exothermic physical process. The Gibbs free energy AG is less than 0, so the adsorption process can occur spontaneously. the entropy change AS are less than 0, which indicates that the adsorption reduces the degrees of the entire system’s freedom. |
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