Study on optimization of extraction of total flavonoids from Zingiber strioatum by response surface methodology and its antioxidant activity

The effect of ethanol concentration,material- to- solvent ratio,ultrasonic time and ultrasonic temperature on the extraction yield of total flavonoids from Zingiber strioatum was investigated by single factor test in this study.The ultrasonic- assisted extraction conditions were further optimized by the response surface analysis and were determined to be ethanol concentration of 71%,solvent- to- material ratio 21 ∶ 1( m L ∶ g),ultrasonic time of21 min and ultrasonic temperature of 51℃.Under the optimal extraction conditions,the yield of total flavonoids from Zingiber strioatum reached 4.50%. Result of antioxidation showed that the total flavonoids from Zingiber strioatum had good total reduction capabilities,and scavenging hydroxyl radicals,DPPH·,superoxide anion( O-2·),it had good antioxidant activity.