Abstract:In order to determine the optimum conditions of ultrasound-assisted decompression of alcoholic extraction of flavonoid from Osmunda japonica Thunb, the main process parameters were optimized by response surface methodology (RSM) with flavonoid extraction as an indicator. The results of variance analysis showed that the regression model could well reflect the relationship between extraction volume of flavonoids and the ratio of solid to liquid, the volume fraction of ethanol and the temperature of ultrasonic.The optimum extraction processing parameter was ascertained as follows: the solid-liquid ratio 1: 60, the volume fraction of alcohol 49.97%, ultrasonic temperature 70.19℃, ultrasonic time 70 min, ultrasonic power 300 W, and extraction pressure 0.08~-0.1 MPa. Under these conditions, the yield of flavonoids extracted from Osmunda japonica Thunb was (118.924 ± 1.950) mg/g. Antioxidant test results showed that: the IC50 of flavonoids extracted from Osmunda japonica Thunb by decompression-ultrasonic and atmospheric pressure ultrasonic extraction for 1,1-diphenyl-2-picrylhydrazyl (DPPH) were 0.117 and 0.119, respectively. The IC50 of 2,2‘-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid)(ABTS+) were 0.072 and 0.076, respectively. The total reducing power: decompression- ultrasonic > atmospheric pressure ultrasonic > Vc. Under the same extraction conditions, the extraction of flavonoids by decompression-ultrasonic extraction method was 20.01 ± 1.64 mg/g higher than that by ultrasonic extraction, and the antioxidant activity of flavonoids was not affected.
