Optimization of the Ultrasound Extraction Technology and Antioxidant Activity Analysis of the Total Flavonoids from Debregeasia orientalis Leaves by Box-Behnken Method

Using Debregeasia orientalis leaves as raw materials, the Box-Behnken model was designed by single factor experiments and the optimal technological conditions for extracting total flavonoids from Debregeasia orientalis leaves were optimized, and the antioxidant activity in vitro was evaluated. The results showed that the ethanol concentration, liquid-material ratio, ultrasonic time and ultrasonic temperature were 35%, 42 mL/g, 47 min and 70 ℃, respectively, which were consistent with the predicted values of Box-Behnken model. The average extraction rate of total flavonoids from Debregeasia orientalis leaves was 3.15%±1.82%. Under these conditions, the total antioxidant capacity of extract was equivalent to 1.969 mmol/L (FeSO₄ equivalent value), and the IC₅₀ of DPPH free radical scavenging rate was 0.075 mg/mL, which indicated that the total flavonoids of the extract from Debregeasia orientalis leaves could exhibit good antioxidant activity, and provide certain theoretical data support for further research and development of wild resources of Debregeasia orientalis.