Purification with macroporous resin and antioxidant activity of polyphenols from sweet potato leaves

In this study, polyphenols from sweet potato leaves were purified by macroporous resin, and antioxidant activity was evaluated by free radical scavenging. AB-8, D-101, HPD-100 and DM301 four resins were selected for purification. The antioxidant activity was evaluated by 2,4-dinitrophenylhydrazine (DPPH) and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS) methods. The results showed that the DM-301 macroporous adsorption resin was most suitable by static adsorption–desorption method, and the optimal purification conditions were determined by single factor experiment as follows: the concentration of sample solution 6.0 mg/mL, the flow rate of sample solution 60 mL/min, the volume fraction of ethanol desorption 60%, and the flow rate 40 mL/h. The scavenging rates of DPPH and ABTS free radicals by purified polyphenols from sweet potato leaves were 74.04% and 98.20%, respectively. The research results provide reference for further development and utilization of polyphenols from sweet potato leaves.