Study On Extraction And Separation Of Alfalfa Flavonoids

Alfalfa contains many kinds of biological activity components, such as saponin, flavonoids, leaf protein and so on. Flavonoids is an important type of them. To study the value of flavonoids in alfalfa, different methods were adopted to extract and separate flavonoids systematically.Experiment 1: To examine and figure out the content of flavonoids, the working calibration curve based on rutin standard solutions was made. The regression line was C=83.332A+0.3619,(R=0.9993).Experiment 2: The effect of concentration of ethanol solution on extraction ratio of flavonoids was studied. The result showed that 30% ethanol solution had the best effect on flavonoids extraction. The colour got deeper and deeper with the increase of ethanol solution concentration.Experiment 3: The effect of different pH value on extraction ratio of flavonoids and the content of flavonoids in the extractive were studied. The highest extraction ratio was 4.87 mg/g when PH was 7.5 and the highest content of flavonoids in the extractive was 1.61% when PH was 9.0.Experiment 4: The effect of different store conditions and different part sampled on extraction ratio of flavonoids were studied. Extraction ratio was 0.188‰more when the sample was stored with -30℃and without light than stored under room condition. The content of flavonoids in the leaf of the three treatment were 1.53mg/g, 0.86mg/g, 1.16mg/g higher than in the whole plant, respectively.Experiment 5: Different macroporous resins separeted flavonids in the ethanol solution extractive. DS-17 showed the best separation effect. The content of flavonoids in the extractive is 5.87%.Experiment 6: The effective factors on extraction of alfalfa flavonoids by acid-isolation were carried out. The result showed that the optimum pH was 2.2 for extraction of alfalfa flavonoids. The content of flavonoids in the extractive is 9.80%.Experiment 7: The effect of concentration of ethanol solution on separation of acid-isolation extractive and diffferent assistance medthods on separation of alfalfa flavonoids were carried out. The result showed that the optimum concentration of ethanol solution was 60% and the content of alfalfa flavonoids was 8.35%. The content of alfalfa flavonoids in the extractive by ulrtafiltration membrane was 1.05% lower than in the extractive by ethanol solution and. The content of alfalfa flavonoids in the rest of separation extractive was 0.79%, higher than in the extractive by ethanol solution. The content of alfalfa flavonoids in the extractive by centrifugation was 2.07% which was 0.42% higher than in the extractive by ethanol solution.Experiment 8: The effect of macroporous resins on separation of alfalfa flavonoids in the extractive by acid-isolation was carried out. The result showed that DM130 all had the best effect in the three treatments. The highest content of flavonoids in the extractive were 24.25%, 72.15%, 29.35%, respectively.Experiment 9: The effect of high room temperature in summer on absorption capacity of macroporous resins was studied. The result showed that high temperature decreased the absorption capacity of macroporous resins. The new impurity was added in the course of separation of flavonoids.Experiment 10: The effect of different oganic solvents on isolation of flavonoids were carried out. The result showed that acetidin and acetone could increase the content of alfalfa flavonoids with 6.27% and 2.4% in the extractive, respectively.