Optimization of extracting total flavonoids from Phyla nodiflora ( L.) by response surface methodology and its antioxidant activity

Objective: To explore the optimum extraction process of total flavonoids from Phyla nodiflora ( L.) and evaluate the antioxidant activity. Methods: Based on the single- factor tests, the extraction conditions of total flavonoids from Phyla nodiflora ( L.) were optimized by response surface methodology. Meanwhile, the antioxidant activity of total flavonoids was assessed by scavenging assays of DPPH· and ABTS· Results: The optimum extraction conditions were as follows: ethanol concentration 74%, liquid- solid ratio 1 ∶ 30, extraction temperature72℃ and extraction time 115 min. Under the optimal conditions, the extraction rate of total flavonoids was 1.59%, which was close to the predicted value 1.60% with 0.63% bias.In addition, DPPH· and ABTS· radical scavenging capacity of total flavonoids was better, and IC50 of it was 7.67μg / m L and 12.88μg / m L, respectively.