Purification Process of Total Flavonoid in Sweet Tea by using the Macroporous Resin and Its Antioxidant Activity

On the basis of static adsorption and desorption and static adsorption kinetics of 12 macroporous resins,the effects of sample solution and eluent ethanol concentration on the dynamic adsorption and desorption rate of macroporous resin were studied. The DPPH· scavenging ability and total antioxidant capacity(T-AOC)of crude flavonoids and refined flavonoids were compared and analyzed with vitamin C and rutin as control groups. Results showed that,HPD-450 macroporous resin was the best macroporous resin for the separation and purification of total flavonoids from sweet tea. The optimum purification conditions were as follows:The concentration of sample solution was 1.2875 mg/mL,and the sample amount of 100 mL(the ratio of sample volume to resin mass was 10:3). The sample solution was eluted with 2 BV water and 170 mL 55% ethanol at the flow rate of 1.5 BV/h. The average purity of purified flavonoids was 31.79% and the average recovery was 90.49%. The IC₅₀ values for DPPH· were 0.0187,0.0202,0.0175 and 0.0265 mg/mL,respectively,which showed that crude flavonoids of sweet tea had stronger scavenging ability to DPPH· than refined flavonoids,the DPPH· scavenging ability of crude flavonoids and refined flavonoids was lower than vitamin C,but higher than rutin. The effect of total antioxidant capacity(T-AOC)was evaluated. In the group of 0.02 mg/mL,the total antioxidant capacity of crude flavonoids in sweet tea was significantly(P<0.05)higher than in other groups. In 0.03,0.04 mg/mL groups,the total antioxidant capacity of crude flavonoids from sweet tea was higher than that from refined flavonoids,but there was no significant difference between the two groups,and both of them were significantly(P<0.05)higher than vitamin C.