Optimization of Extraction Process for Flavonoids from Polygomun aviculane L.by Response Surface Methodology

Ultrasound assistance was applied to extract flavonoids from Polygomun aviculane L.using aqueous ethanol as extraction solvent.Four main factors(extraction time,ultrasound power,ethanol concentration and solid-to-liquid ratio)affecting the yield of flavonoids were optimized by response surface methodology.The results showed that the optimal extraction conditions were extraction time of 39 min,ultrasound power of 70 W,ethanol concentration of 65%,and solid-to-liquid ratio of 1:21(g/mL).Under these conditions,the observed yield of flavonoids was 20.07 mg/g,and the relative error in comparison with the predicted one was 1.1%,suggesting that the optimal extraction conditions are reliable.