Optimization of Ultrasonic-Assisted Extraction and Antioxidant Activity of Total Flavonoids from Zanthoxylum bungeanum Maxim Fruit Peel

With the aim of developing an ultrasonic-assisted procedure for the extraction of total flavonoids from Zanthoxylum bungeanum Maxim fruit peel,we performed an orthogonal array design based on one-factor-at-a-time experiments to determine optimal extraction conditions.A 45% ethanol/water solution was found to be the best solvent for total flavonoids and the optimal solid-to-solvent ratio was 1:30(g/mL).An extraction duration of 50 min was found to be optimum.Under these conditions,the yield of total flavonoids was spectrometrically determined to be 3.56%.The IC50 values of the obtained extract for scavenging DPPH and hydroxyl free radicals were 0.855μg/mL and 132.18μg/mL,respectively.Moreover,the total flavonoids extracted from Zanthoxylum bungeanum Maxim fruit peel possessed stronger reducing power than BHT.