Optimization of process for microwave- assisted extraction of polyphenols from burdock and its antioxidant activity

The microwave- assisted extraction process and antioxidant activity of total phenols and flavones from burdock were studied. To optimize the process of polyphenol extraction from burdock,the response surface methodology with three factors at three levels was adopted on basis of single factor experiments.Model fitting and regression analysis of experimental data showed that two significant factors which influenced total phenol yields were ethanol concentration and liquid ratio,and one significant factor which influence flavone yields was ethanol concentration.The results showed that the optimal extraction conditions were the presence of microwave power140 W,72% ethanol solvent,extraction time 2.5 minutes and liquid ratio 1∶36g / m L.Under the optimal conditions,the yield of total phenols and flavones from burdock reached 129.68 mg / g and 23.56 mg / g respectively.The polyphenol extraction from burdock showed a certain ferric ions chelating ability( IC500.288 mg / m L) and strong DPPH radical scavenging activity( IC501.12 mg / m L).