Supercritical CO(2) extraction, chemical composition, and antioxidant effects of Coreopsis tinctoria Nutt. oleoresin

Coreopsis tinctoria Nutt. was used to extract oleoresin through supercritical CO(2) extraction technology. The extraction conditions were optimized using response surface methodology, and the chemical composition of C. tinctoria Nutt. oleoresin (CTO) was analyzed. Under the optimal conditions, the antioxidant activity of oleoresin was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH˙) and 2,2′-azino-bis-(3-ethylbenzo-thiazoline-6-sulphonic acid)diammonium salt (ABTS˙(+)) free radical scavenging assays. The optimal extraction conditions were a 27.5 MPa extraction pressure, a 45°C extraction temperature, and a 3 h extraction time. Under these extraction conditions, oleoresin yield was up to 3.163%. Compared to steam distillation extraction, the CTO extracted using supercritical CO(2) had more abundant components. The EC(50) of CTO for DPPH˙ and ABTS˙(+) free radical scavengers was 1.54 and 1.07 mg/mL, respectively.