Department of Food Engineering, Shaanxi Normal University, Xi'an, People's Republic of China.
J Enzyme Inhib Med Chem. 2009 Dec;24(6):1280-7. doi: 10.3109/14756360902829741.
Enzyme-assisted water extracts (EWEDL) and ethanol extracts of Du-zhong leaves (EEDL) were evaluated for their antioxidant activities using the DPPH radical-scavenging assay, Fe(2+)-chelating assay, and inhibition ability of the linoleic acid peroxidation assay. In general, the antioxidant activity of Du-zhong leaf extracts increased with increasing concentration. Based on the two extracting methods with different antioxidative reactions, it was shown that the enzyme-assisted water extracting method was more effective for antioxidant extraction from Du-zhong leaves. By HPLC-MS analysis, the main phenolic compounds (geniposidic acid, epicatechin, and chlorogenic acid) identified in EWEDL and EEDL were similar. EWEDL and EEDL had total phenolic contents of 13.84 +/- 0.11 and 14.72 +/- 0.14 mg chlorogenic acid equivalents (CAE) in each gram of extract, respectively. However, there was no positive correlation between total phenolic content and antioxidant activities of EWEDL and EEDL measured by the three different assays.
酶辅助水提物（EWEDL）和杜仲叶乙醇提取物（EEDL）的抗氧化活性采用 DPPH 自由基清除 assay、Fe(2+)-螯合 assay 和抑制亚油酸过氧化 assay 进行评价。一般来说，杜仲叶提取物的抗氧化活性随着浓度的增加而增加。基于两种具有不同抗氧化反应的提取方法，表明酶辅助水提方法更有效地从杜仲叶中提取抗氧化物质。通过 HPLC-MS 分析，在 EWEDL 和 EEDL 中鉴定出的主要酚类化合物（京尼平酸、表儿茶素和绿原酸）相似。EWEDL 和 EEDL 每克提取物中总酚含量分别为 13.84 ± 0.11 和 14.72 ± 0.14mg 绿原酸当量（CAE）。然而，通过三种不同的 assay 测量的 EWEDL 和 EEDL 的总酚含量与抗氧化活性之间没有正相关关系。
