Study on Enzymatic-ultrasonic Assisted Extraction of Total Flavonoids from Polygonatum Sibirici and Its Antioxidant Activities

OBJECTIVE To study the optimum extraction technology for the total flavonoids from Polygonatum sibiricum(TFPS) by enzymatic-ultrasonic method, and to research its antioxidant activities. METHODS Using total flavonoids compounds as investigation indexes, single factor and orthogonal test were used to investigate the cellulase amount, ethanol concentration, liquid-solid ratio and ultrasonic time, and the extraction technology was optimized. Furthermore, the antioxidant activities of TFPS were evaluated, using various antioxidant assays included the scavenging on DPPH, ABTS⁺ and ferrous ion-chelating capacity. RESULTS The optimum extraction conditions were as follows:cellulase amount was 0.75%, ethanol concentration was 40%, liquid-solid ratio was 20 mL·g^-1, ultrasonic time was 30 min, and extraction rate of total flavonoids was 1.595%. TFPS had strong scavenging activity on ·DPPH and ABTS⁺ free radicals, the IC₅₀ was 27.55, 11.47 μg·mL^-1, and also had strong ferrous ion-chelating capacity, the IC₅₀ was 32.26 μg·mL^-1. CONCLUSION The enzymatic-ultrasonic method is stable, feasible and has the advantage of high extraction efficiency, and can be used for the extraction of TFPS. These results show that TFPS has strong antioxidant activity under the optimal extraction technology.