Study On Extraction And Refinement Of Flavonoids And Its Antioxygenic Activity From Paddy Hull

In this paper, the methods and conditions for extracting, separating and oxidationresistant of flavonoids from Paddy Hull were studied in detail, the optimal methodology for extracting and separating was set up.Then the structure types of flavonoids were identified initially. All these laid a good foundation for Paddy Hull flavonoids in exploitation and application for health food and Chinese pharmacy.At first, the extraction of flavonoids from Paddy Hull was studied. During the extracting process, five main factors including extracting solvent concentration, extraction temperature, extraction time, ratio of solvent to sample and extraction times were studied by using single factor analysis method. The optimal process conditions were obtained by orthogonal L₉(3⁴) analysis as follows: ethanol concentration 50%, extraction temperature 70℃,extracting during 6 h , ratio of solvent to samplel:30 and extracting for three times. Before these, the methods of AlCl₃(λ_max=275nm) could be adopted in the determination of flavonoids content in Paddy Hull by means of various color-reaction and their UV character.Then,the purification for the flavonoids extracts from Paddy Hull was studied. Through the comparison the performance of adsorption and desorption of five kinds of macropore adsorption resins to flavonoids from Paddy Hull, AB-8 was selected to purify the flavonoids extracts from Paddy Hull. The best conditions of adsorption and desorption were established by means of single factor and orthogonal test.Moreover,the leaking curve of dynamic adsorption and the dynamic desorption curve were examined,and the appropriate volume of solution loaded and the eluent volume were established.According to the optimal conditions of adsorption and desorption, after enriched by AB-8 resin,the purity percentage of flavonoids extracts from Paddy Hull was increased 3.09 times,achieved a goal of enrichment and separation.Through the color-reaction of flavonoids extracts from Paddy Hull with special reagent and the character of PPC,TLC,UV,IR,HPLC of flavonoids, the basic structures were judged.The result suggested that the main ingredient in flavonoids extracts from Paddy Hull was a compound with 5,7and 4'-OH,C-glycoside.Finally, the oxidationresistant experiments were studied by the different concentration of flavonoids from Paddy Hull,Vc and BHT, such as reducing power, scavenging activity on 1,1-diphenyl 2-picrylhydrazyl (DPPH·),superoxide radical(O₂^-) and hydroxyl radical(·OH) , the inhibiting on peroxidation from livetin and lard oil, showed that the flavonoids of Paddy Hull had a strong scavenging activity on DPPH·,O₂^-,·OH,and the scavenging activity strengthen by the solution concentration boosting. Moreover,the results also indicated that the inhibiting of Paddy Hull flavonodis on peroxidation from polyunsaturated fatty acid(PUFA) was effective, the inhibiting strengthen by the solution concentration boosting in reaction system.And the experiments of the inhibiting on lard oil oxidation was to proved that the flavonoids of Paddy Hull have a better antilipid peroxidation ability.