Optimization of Extraction Process of Total Flavonoids from Inula lineariifolia and Its Antioxidant Activity

The optimization of the extraction process of total flavonoids from Inula lineariifolia was achieved by response surface methodology and its antioxidant activity were evaluated. The yield of total flavonoids was taken as the index to study the effect of ethanol concentration,extracting temperature,liquid/solid ratio and extracting time. Based on the single factor experiments,the four factors and three levels of response surface analysis method was taken to determine the extraction of total flavonoids from Inula lineariifolia. The results showed that the optimum extraction conditions were as follows:Ethanol concentration 70%,extracting temperature 87 ℃,liquid-solid ratio 31:1 mL/g,extracting time 40 min. Under the conditions,the yield of total flavonoids was(33.62±0.0207) mg/g. The scavenging ability of total flavonoids from Inula lineariifolia on DPPH radical(IC₅₀=0.074 mg/mL)was stronger than that of V_C(IC₅₀=0.082 mg/mL),but the scavenging ability of hydroxyl radical was obviously weaker than V_C. The extraction process of total flavonoids from Inula lineariifolia which optimized by response surface methodology was stable and practicable. Moreover,the total flavonoids obtained under optimum extraction conditions had strong antioxidant activity,which provided a theoretical basis for the development of total flavonoids from Inula lineariifolia.