Study On Extraction, Purification And Antioxidant Activity Of Total Flavonoids From Oenothera Biennis L. Leaves

In this experiment，the study of extraction，purification and antioxidant activity ofOenothera biennis L.leaves total flavonoids were conducted with Oenothera biennis L.leavesin Huocheng，Yili，Xinjiang as raw materials and total flavonoids as studying object. Thestudy results could provide a certain theoretical foundation for comprehensive utilization andfurther development of Oenothera biennis L.leaves.The main contents and results of thisresearch are as follows：1、The extraction of Oenothera biennis L.leaves total flavonoids was studied with themethods of ethanol extraction. The extraction conditions of total flavonoids were optimizedby L9(34)orthogonal experiments and the optimal conditions of total flavonoids extracted fromOenothera biennis L.leaves by using ethanol extraction were as follows：The optimumconditions were methanol concentrations80%，extraction time2h， the ratio of solid to liquid1:30. In this process，the main factor affecting the extraction of total flavonoids is theconcentration of methanol，followed by the extraction time，then the ratio of solvent tomaterial.Under the optimal conditions，the extraction rate of Oenothera biennis L.leaves totalflavonoids reached5.15%.The quantitative analysis methods of Oenothera biennis L.leavestotal flavonoids were established with the methods of UV-vis spectrophotometry withNaNO2-Al(NO3)3-NaOH as colour-developing reagent and rutin as standard sample. Themethod had good precision，stability reproducibility and the average recovery rate was high.2、The separation and purification of Oenothera biennis L.leaves total flavonoids were studiedwith the method of macroreticular resins. The major factors which had influence on static anddynamic adsorption and desorption of macroreticular resins were investigated.The separationand purification conditions of Oenothera biennis L.leaves total flavonoids wereoptimized.The experiment results of static adsorption and desorption of three kinds ofmacroreticular resins showed that the adsorption and desorption effects of AB-8was ideal.The optimal static adsorption and desorption conditions of AB-8were as follows：AB-8type macroporous resin，adsorption solvent into water，pH value of sample is4.75，the eluantand density of concentration is70%alcohol，concentration of total flavonoids of sample is3mg/ml and29ml on sample amount，current velocity of2ml/min，elution volume100ml.Under the optimal conditions，the extraction rate of Oenothera biennis L.leaves totalflavonoids reached49.13%.Using UV，colorful reaction to response to purified qualitativeidentification，the results further show that Oenothera biennis L.leaves contain flavonoids.3、In the experiment of in vitro anti-oxidation，the spectrophotometry method was used todetermine the content of the flavonoids and the scavenges of hydroxyl radicals andsuperoxide anions；The MDA spontaneous lipid peroxidation in liver and erythrocytehemolysis formation of mouse，were determined by TBA colorimetry，and the lipidperoxidation in liver and erythrocyte hemolysis induced by H2O2were determined withspectrophotometers.The results showed that Oenothera biennis L.leaves have the effect of thescavenging radicals， reducing power and the anti-lipid oxidation and hemolysis oferythrocyte.