泡桐花总黄酮的提取工艺优化及抗氧化活性

该研究采用超声波辅助纤维素酶法提取泡桐花总黄酮。在单因素试验的基础上，选择酶解温度、超声功率、液料比和酶解时间进行Box-Benhnken试验设计，响应面法优化泡桐花总黄酮提取工艺，并测定其抗氧化能力。结果表明，泡桐花总黄酮最佳提取工艺条件为酶解温度50 ℃，超声功率240 W，液料比40∶1（mL∶g），酶解时间36 min。在该优化提取条件下，总黄酮的提取得率为7.82%，与模型预测值8.01%接近。抗氧化试验结果表明，泡桐花总黄酮对DPPH自由基、羟自由基和ABTS自由基的半抑制浓度（IC50）值分别为214.2 μg/mL、200.7 μg/mL和328.5 μg/mL，在总黄酮质量浓度为800 μg/mL时，总黄酮对三者的清除率分别为83.1%、75.4%和64.3%。

Extraction process optimization of total flavonoids from Paulownia fortunei flowers and its antioxidant activity

The total flavonoids were extracted from Paulownia fortunei flowers by ultrasonic-assisted cellulase method.Based on the single-factor test,enzymolysis temperature,ultrasonic power,liquid-solid ratio and enzymolysis time were selected for the Box-Benhnken test design.The extraction process was optimized by response surface methodology and the antioxidant capacity was determined.The results showed that the optimal extraction conditions were enzymolysis temperature 50℃,ultrasonic power 240 W,liquid to solid ratio 40∶1(ml∶g)and enzymolysis time 36 min.Under the optimal extraction conditions,the extraction yield of total flavonoids was 7.82%,which was close to the model prediction value of 8.01%.The results of the antioxidant test showed that the half inhibitory concentration(IC50)of P.fortunei flowers total flavonoids on DPPH radicals,OH radicals and ABTS radicals were 214.2μg/ml,200.7μg/ml and 328.5μg/ml,respectively.With the total flavonoid concentration of 800μg/ml,the clearance rates of total flavonoids to the three free radical were 83.1%,75.4%and 64.3%,respectively.