桑叶黄酮的提取纯化及对油脂抗氧化活性的研究

采用不同的方法（有机溶剂、稀盐和酶法）提取桑叶中的黄酮类化合物,比较不同提取方法的提取率、提取物中黄酮类化合物的含量及纯度,从而探讨最佳的提取方法,用AB-8型大孔吸附树脂为层析柱填充料,对桑叶黄酮的提取物进行了纯化.以猪油为底物,采用碘-硫代硫酸钠滴定法测定了所得黄酮类化合物对猪油的抗氧化活性.结果表明：桑叶中黄酮类化合物的最佳提取溶剂是60%丙酮,采用有机溶剂（60%丙酮）和稀盐（3%硫酸铵）的二步提取法在提取效果、成本、安全性等方面均优于有机溶剂的一步提取,而纤维素酶乙醇提取法效果最佳.AB-8型大孔吸附树脂对桑叶黄酮类化合物进行纯化效果明显.桑叶黄酮对猪油具有明显的抗氧化作用,且有剂量效应关系,尤其是经过纯化工艺后的黄酮类化合物,其抗氧化效果显著,是一种良好的天然抗氧化剂.

Extraction, Purification and Anti- oxidation Evaluation of Flavonoids from Morus aLba L. Leaves

The extraction method of flavonoid from leaves of Morus aLba L.and the anti-oxidation activity of the extract were studied.AB-8 macro-reticular adsorptive resin was used to refining the flavonoids.The anti-oxidation activity of the product was evaluated using lard as the substrate;peroxide value(POV) was determined according to the method in GB/T 5009.37-1996.The results show: the optimum extracting solvent for flavonoid from leaves of Morus aLba L.is 60% acetone;two step extraction by using 60% acetone and 3% ammonium sulfate is better than one step extraction using organic solvent in extraction effect,cost and safety.AB-8 macro-reticular adsorptive resin is a perfect adsorbent to refine the extracted flavonoids.It is proved that flavonoids in leaves of Morus aLba L.,especially the purified product,is a good natural antioxidant.