Optimization of extraction, purification process and antioxidation activity of polyphenols from Flos Trollii

In order to improve the high-value utilization of the Flos Trollii polyphenols, the ethanol volume fraction, solid-liquid ratio and extraction time were studied by single-factor and response surface methodology (RSM) experiments to optimize the ultrasonic-assisted solvent extraction conditions of Flos Trollii polyphenols. The best macroporous adsorption resin was selected to purify the polyphenols, and the free radical scavenging ability, total antioxidant capacity and reducing power of the polyphenols before and after purification were determined. The results showed that the optimal extraction conditions were extraction time of 36 min, ethanol volume fraction of 32%, and liquid-solid ratio of 13 mL/g. Under these conditions, the polyphenols content of Flos Trollii was the highest and reached (40.14±0.24) mg/g. D101 macroporous adsorption resin was selected as the best resin for purifying polyphenols. Under the conditions of 1.5 mg/mL of the initial polyphenols concentration, adsorption rate of 1 mL/min, 60% ethanol as eluent after adsorption equilibrium, elution flow rate 1 mL/min, the purity of polyphenols increased by 4.88 times from 9.35%±0.12% to 55.04%±0.18% (P<0.05). The purification significantly improved the in vitro polyphenols of Flos Trollii antioxidant capacity. In summary, ultrasonic-assisted extraction and D101 macroporous adsorption resin purification not only effectively extract and purify polyphenols from Flos Trollii, but also improve its antioxidant capacity at the same time, which provides a theoretical basis for the development of Flos Trollii functional foods.