Asparagus In The Extraction Of Flavonoids And Purification Process

In this paper, the technological conditions of extraction and purification of flavonoids from asparagus was studied. Then flavonoids were proved to be flavonol by color reaction and UV spectrum.Firstly, using spectrophotometry plotted the standard curve of flavones. The regression equation was C=0.1285A-0.0003 and the correlation coefficient r was 0.9993. Through comparing different extraction technologies in extracting flavones from asparagus L., results indicated that alcohol soaking was the optimal extraction method. By orthogonal design, the optimum technology parameters had been obtained as follows: the concentration of alcohol was 60% (v/v), the ratio of material and alcohol was1:30(w/v), the time of extraction was 4 hours and the temperature was 80 °C. The flavones can be obtained in the proportion of 0.498% under this condition.Then, the paper studied the extraction technology of asparagus's flavonoids with supercritical carbon dioxide extraction for the first time. The optimum technique conditions were determined as follows: the pressure was 30Mpa, the temperature was 70°C, the time was 2 hour and the quantity of entrainers was 2.0mL/g. With these conditions, the flavones's extraction rates could reach 1.35%, which was 2.7 times of alcohol extraction.At last, the purification of flavonoids was studied after extracting flavonoids from asparagus. The optimal conditions were as follows: the macroporous adsorption resin AB-8 was selected as exclusive separation resin of asparagus' flavonoids, the adsorption velocity was 2mL/min, the elution velocity was 1.5 mL/min, the pH value of under-adsorpted solution was 6, the elution solvent was more than 70% alcohol, and the quantity of elution solvent was 200mL. Finally, the flavonoids of product are detected as flavonol by color reaction and spectrum.