探究微波辅助离子液体提取罗布麻叶总黄酮的最佳提取工艺，并评价其抗氧化活性。先通过单因素试验确定离子液体类型，筛选出工艺中影响总黄酮提取量的显著性因素，后设计“三因素五水平”的中心组合试验优化提取条件，并建立响应面数学模型。试验所得最佳工艺为：离子液体浓度0.73 mol/L、液料比19:1 mL/g、微波时间10 min、微波功率483 W、温度70 ℃，此条件下总黄酮提取量的平均值为14.10±0.202 mg/g，与模型的预测值基本吻合，提取量较传统提取工艺有明显提高。对提取量影响最显著的三个因素依次是离子液体浓度、液料比、微波功率。抗氧化活性试验显示，羟自由基和DPPH自由基的清除率随罗布麻叶总黄酮质量浓度的升高而增大，均表现出较好的量效关系，对应的IC50值为27.88 μg/mL、13.61 μg/mL，分别是Vc的1.71、2.26倍，表明罗布麻叶总黄酮具有较强的抗氧化能力。

The optimal ionic liquid-based microwave-assisted extraction process of the total flavonoids from Apocynum venetum L. leaves was investigated, and the antioxidant activity of the extract was evaluated. Firstly, the type of ionic liquid was determined in single factor experiments, and the significant factors affecting the extracted amount of total flavonoids in the process were screened out. The extraction conditions were optimized by the central composite post-design with three factors and five levels and the response surface mathematical model. The optimum process conditions were as follows: ionic liquid concentration 0.73 mol/L, liquid-solid ratio 19:1 mL/g, microwave time 10 min, microwave power 483 W, temperature 70 ℃. Under these conditions, the average extraction rate of total flavonoids was 14.10±0.202 mg/g (which was essentially consistent with the predicted value), and the extraction yield was significantly improved compared with that for the conventional extraction process. The three factors affecting the most the extraction yield were ionic liquid concentration, liquid-solid ratio, and microwave power. The results of the antioxidant activity experiments showed that the scavenging rate of ?OH radical and DPPH free radical increased with the increase of the concentration of total flavonoids from Apocynum venetum L. leaves, and exhibited a good dose-effect relationship. The corresponding IC50 values were 27.88 and 13.61 μg/mL (which were 1.71 and 2.26 times of those for Vc, respectively), indicating that the total flavonoids from Apocynum venetum L. leaves had strong antioxidant capacity.

广东中烟工业有限责任公司科技项目(粤烟工05XM-QK[2015]001)