广玉兰花总黄酮提取及其抗氧化活性研究

目的]筛选广玉兰花中总黄酮的提取方法，并研究其抗氧化活性。方法]采用乙醇回流提取法对广玉兰花中总黄酮进行提取，采用单因素试验和正交试验考察乙醇浓度、提取温度、料液比和提取时间对总黄酮提取效果的影响，通过超氧阴离子自由基（O2-·）和羟自由基（·OH）的清除试验，对广玉兰花总黄酮的抗氧化活性进行研究，并与维生素C和抗氧化剂特丁基对苯二酚（TBHQ）进行比较。结果]利用单因素试验和正交试验确定最佳提取工艺条件为：乙醇浓度70％，料液比1：40（g／ml），提取时间90min，提取温度70℃；在该提取条件下，总黄酮平均含量为4．896％，总黄酮平均纯度为32．925％。广玉兰花总黄酮对自由基的清除率随总黄酮浓度的增大而上升，总黄酮清除O2-·及·OH的肥。值分别为0．3810和0．6406mg／ml。广玉兰花总黄酮清除自由基的能力高于Vc，低于抗氧化剂TBHQ；但当总黄酮浓度达到0．7092mg／ml时，其抗氧化效果接近于TBHQ。结论]广玉兰花总黄酮具有明显体外抗氧化作用，是一种极具开发价值的天然抗氧化物质。

Study on the Extraction and Antioxidant Activity of Total Flavones from Magnolia grandiflora Linn

Objective ] To select extraction method for total flavones from Magnolia grandiflora Linn and study its antioxidant activity. Method] Total flavones were extracted from Magnolia grandiflora by using ethanol reflux extraction method, and the effects of ethanol concentration, extraction temperature, solid - liquid ratio and extraction time on the extraction efficiency of total flavones were separately investigated by using single - factor test and orthogonal experiment. Antioxidant activities of total flavones from Magnolia grandiflora Linn were studied by superoxide anion radical and hydroxyl radicals scavenging tests, and compared with vitamin C and antioxidants TBHQ. Result ] The optimum extraction conditions were as follows ： ethanol： 70%, solid - liquid ratio ： 1：40, extraction time ： 90 min, extraction temperature ：70 ℃. The average content of total flavones was 4. 896%, and the purity of total flavones averaged 32. 925%. The results show that, the clearance rate of total flavones from Magnolia grandiflora Linn on free radical raised with the increasing of the concentration of total flavones. The IC50 values of scavenging superoxide anion radicals and hydroxyl radicals of total flavones were 0. 381 0 and 0. 640 6 mg/ml. The capacity of scavenging free radical of total flavones from Magnolia grandiflora Linn is higher than Vc, but lower than TBHQ. When the concentration of total flavones was 0. 709 2 mg / ml, the antioxidant effect close to TBHQ. Conclusion] The total flavones from Magnolia grandiflora Linn as a natural antioxidant substance of great exploitation value have significant in vitro antioxidant effect.