Orange peel flavonoids were extracted by enzymatic hydrolysis ultrasonic extraction method.The effects of cellulase concentration,ultrasonic time,ethanol concentration,ratio of material to liquid on yield of flavone were determined. The optimal extraction conditions of orange peel flavone were as follows: cellulase concentration 0. 5 g/mL,ultrasonic time 60 min,volume concentration of ethanol 90 %,and material-to-liquid ratio 1∶60 (g/mL). Using coumarin-3-carboxylic acid (CCA) fluorescence method and methyl thiazoly1 tetrazolium (MTT) assay,it...