Abstract: The effect of ethanol concentration,material-to-solvent ratio,ultrasonic time and ultrasonic temperature on the extraction yield of total garlic flavonoids 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 80%,material-to-solvent ratio of 1:16,ultrasonic time of 18 min and ultrasonic temperature of 53 ^oC.Under the optimal extraction conditions,the yield of total garlic flavonoids reached 3.99%.In addition,the pyrogallol autoxidation test indicated that the inhibition rate of superoxide anion radical (O₂^-·) of the garlic extract was 60.43%.The result proved that garlic total flavonoids had relative strong antioxidant activity.

Key words: garlic, total flavonoids, response surface, antioxidant activity