Optimization of Extracting Flavonoids from Isatidis Radix by Response Surface Methodology and Its Antioxidant Activity

OBJECTIVE To explore the optimum extraction process of flavonoids from Isatidis Radix and evaluate its antioxidant activity. METHODS Based on the single-factor tests, the extraction conditions of total flavonoids from Isatidis Radix were optimized by response surface methodology. Meanwhile, the antioxidant activity of flavonoids was assessed by scavenging assays of 1,1-diphenyl-2-picrylhydrazyl(DPPH). RESULTS The optimum extraction conditions were as follows: ethanol concentration was 60%, liquid-solid ratio was 1∶24.1, and extraction time was 29 min. Under the optimal conditions, the extraction rate of total flavonoids was 54.4 mg·g^-1. DPPH radical scavenging capacity of flavonoids was good. CONCLUSION The target of extracting flavonoids compound efficiently from Isatidis Radix has been achieved by the optimized technology.