Optimization of Ultrasound-Assisted Aqueous Two-Phase Extraction of Flavonoids from Erigeron breviscapus by Response Surface Methodology

To evaluate the effectiveness of the combination of ultrasound-assisted extraction with aqueous two-phase separation and establish the optimal extraction conditions. Ultrasound- assisted propyl-alcohol ammonium sulfate aqueous two-phase extraction of flavonoids from Chinese herbal Erigcron breviscapus was investigated. Response surface methodology, based on a five levels, four variables central composite designs was employed to study the effect of extraction conditions on the extraction yield of total flavonoids. An experimental extraction yield of 6.12 % was achieved under the optimal extraction conditions of 59.3 % propyl-alcohol concentration, 25 of liquid/solid ratio, 25 min of extraction time and 29.5 % of ammonium sulfate concentration, which was agreement well with the optimal prediction value of extraction yield (6.15 %). Flavonoids content in extract of ultrasound-assisted aqueous two-phase extraction (36.4 %) was higher than that of conventional ultrasound-assisted extraction (28.3 %).