Optimization, evaluation and identification of flavonoids in Cirsium setosum (Willd.) MB by using response surface methodology

Abstract

Medicinal and edible homologous plant is receiving widespread attention due to its particularity. As an edible wild vegetable, Cirsium setosum (Willd.) MB is used to treat various bleeding diseases. This work aims to investigate the technological conditions for ultrasound assisted extraction of flavonoids in C. setosum (Willd.) MB. Using a Box–Behnken design as an experimental model, the optimum extraction process of flavonoids was studied by response surface methodology. The conditions for optimal parameters were: the ratio of liquid–solid 39.21 mL/g, the volume fraction of ethanol 71.55%, the ultrasonic time 37.76 min and the temperature 65.28 °C. This study demonstrated that flavonoids yield was greatly affected by the solid/liquid ratio as well as ultrasonic temperature, while, ethanol volume fraction and ultrasonic time had less influence during extraction. In contrast to Vc and BHT, the C. setosum (Willd.) MB flavonoids extract had a more potent scavenging ability towards DPPH radicals, hydroxyl radicals and superoxide anions. Furthermore, the reduction activity was much stronger than BHT but slightly weaker than Vc. Four flavonoids, the main contributors to the antioxidant activity of C. setosum (Willd.) MB including rutin, nicotiflorin, diosmin and linarin were identified through UPLC–MS.