Supercritical CO2 extraction of total flavonoids from Iberis amara assisted by ultrasound

Abstract

Iberis amara is used in herbal medicine where it has been shown to have heterogeneous pharmacological effects. In this study, ultrasound-assisted supercritical CO2 extraction (UASCE) of total flavonoids from Iberis amara was optimized. The maximal total flavonoids content (TFC) was achieved at 25 MPa pressure, 46 °C temperature, 0.34 W/mL ultrasonic energy density, which was 18% higher than that obtained with traditional supercritical CO2 extraction. Furthermore, kinetics study showed that ultrasound primarily improves the extraction rate during constant extraction rate period. High correlation (r = 0.78) exists between TFC and antioxidant activity of extracts. Moreover, HPLC analysis revealed that ultrasound introduction can effectively increase the individual concentrations of interested flavonoids (rutin, kaempferol, quercetin, catechin) in extracts in the range from 16.8% to 45.1%. In conclusion, this study suggests that UASCE is a feasible combined technique to produce flavonoids from Iberis amara on an industrial level as well as for analytical purposes.