Optimization of ultrasonic extraction process of polysaccharides from Scutellaria and evaluation of antioxidative activity

Based on results of single factor experiments,Box-Behnken design was employed to optimize the ultrasonic time(X1:20 ~40min),extraction temperature(X2:50 ~70℃) and ultrasonic power(X3:700 ~900W) to obtain a high crude polysaccharides yield from Scutellaria(SPs). The optimal extraction conditions were as follows:ultrasonic time 30 min,extraction temperature 60℃ and ultrasonic power 755 W. Under these conditions,the experimental value was 12.95%,which was well in close agreement with value predicted by the model.Subsequently,the antioxidant activities(including ferric reducing antioxidant power(FRAP) assay,hydroxyl radical and 2,2-diphenyl-1-picrylhydrazyl radical(DPPH) radical scavenging assay) of the crude polysaccharides were evaluated. Results indicated that the crude polysaccharides from Scutellaria had higher antioxidant and stronger radical scavenging activity to be explored as novel natural antioxidants for using in functional foods or medicine.