Optimization of Purification Process of Total Flavonoids from Roots of Cirsium japonicum DC. with Macroporous Resin by Response Surface Analysis and Comparison of Its Anti-bacterial Activity before and after Purification

The purification process of total flavonoids that extract from roots of Cirsium japonicum DC. with macroporous resin was optimized by response surface experiments based on single factor tests, and anti-bacterial activity of flavonoid were compared before and after purification. The static adsorption and desorption performances of different types macroporous resin were observed by static adsorption-desorption experiment for confirmed the best type resin. Then, the best purified process was determined by dynamic adsorption-desorption experiment. Meanwhile, the resistant abilities against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis of two products were detected by filtering paper method. The results showed that D101 was the best purified resin. The optimal parameters for purification were as follows: the sample concentration of 2.96 mg/mL, the sample pH value of 4.97, the sample flow rate of 1.0 mL/min, ethanol concentration of 70.2% eluting agent volume of 180 mL, and desorption rate of 1.0 mL/min. Under these conditions, total flavonoids had a recovery rate of 69.8% and a purity of 67.4%. The results of anti-bacterial test in vitro showed that compared with extract, the diameter of inhibition zone which flavonoid after purification inhibited three tested bacteria were obviously all increasing (P<0.05). Therefore, its anti-bacterial activity was better.