Extraction and Antioxidant Activity Investigation of Total Flavonoids from Ramie Skin

In this study,microwave extraction technology integrated with ethanol and aqueous ammonium sulfate solution two-phase separation was applied to extract total flavonoids from Ramie skin. Based on single factor experiment,ethanol concentration,solid-liquid ratio,the concentration of ammonium sulfate,extraction power and the time of extraction on extraction yield of total flavonoids were investigated. By orthogonal experiment,the optimum extracting conditions were optimized as follows: ratio of solid to liquid was 1: 50 g /mL,the concentration of ammonium sulfate was 0. 2 g /mL,extraction power was 200 W,extraction time was 120 s,the ethanol concentration was 70%,the highest extraction yield reached to 2. 442% under the optimized extraction conditions. In addition,the total flavonoids extract showed scavenging activities on O- ·2and ·OH in the antioxidant activity assays.