Studies On The Extraction And Purification Process Of Total Flavonoids From Radix Tetrastigmae

Radix tetrastigmae is a commonly used Tradittional Chinese Medicine. And the flavonoids compounds of Radix tetrastigmae has been studied, with widely biological and pharmacological value. In this paper, the extraction, purification, and analysis process of flavonoids in Radix tetrastigmae were studied for better developing this resource.NaNO₂ -Al (NO₃)₃ colorimetric method was used for determination of total flavonoids in Radix tetrastigmae. Traditional UV spectrophotometry for the experiment, resulting in a red flocculent precipitate, seriously interfered with absorbance. So centrifugation was used to improve the method, and the improved method is simple and feasible. Flavonoids in Radix tetrastigmae reacts with NaNO₂ -Al (NO₃)₃ to form a stable red complex, and its maximum absorption wavelength is 500nm. Regression equation is A=0.01018C+0.00809, correlation coefficient R=0.99965. The absorbance was linear with the concentration of rutin. The average recoveries for real samples were 98.95%-100.51%.The process for extracting total flavonoids from Radix tetrastigmae with ethanol was studied. By orthogonal experiment, the optimum condition were found. The optimum condition of ethanol extraction is that : the concentration of ethanol 60%(v/v), the ratio of solvent to material 6, the water bath boiled extracting for 2 times, 1.5h per time. Using this technology, the extraction yield of total flavonoids in Radix tetrastigmae was 26mg/g.The static adsorptive and desorptive capacities of 10 types of macroporous resins with different physical properties for flavonoids in the extract were determined to find a suitable resin for their purification. Then, the dynamic adsorption and desorption of the choosed resin were studied. The results showed that resin HPD826 had good adsorptive and desorptive capacities for the flavonoids. The optimum purification condition was that the extact containing 3.2-5.0mg/mL flavonoids poured on the resin at 2BV/h was eluted with 70%(v/v) ethanol at a flow rate of 2BV/h. The flavonoids adsorbed on the resin could be completely eluted within 3BV. The purified product contained 38.40% flavonoids.