The extract was separated from roots of Scutellaria pinnatifida using perculation and pressurized liquid extraction (PLE). A circumscribed central composite (CCC) was used to optimize the effective extraction variables. For achieving maximum extraction yield via PLE the temperature, pressure, static time, dynamic time, and the solvent flow rate were adjusted 65.8 degrees C, 39.2 bar, 12.9 min, 18.9 min, and 0.76 mL/min, respectively. Ferric reducing antioxidant power (FRAP) (mmol/g) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (mg/mL) were evaluated and the highest antioxidant activity was observed from the PLE extract. The total phenolic and flavonoid content was calculated and a good correlation founded between phenolic content and antioxidant activity. The results indicated the root of this plant is a potential source of natural antioxidants and flavonoids. The PLE method is quicker and it has more extraction yield than perculation. (C) 2014 Elsevier B.V. All rights reserved.