Cy5-Fe^2＋-H2O2光度法测定天然抗氧化剂的抗氧化活性

Determination of the Resistance Capability of Natural Antioxidants to Hydroxyl Radical by Photometric Method with Cy5-Fe^(2+)-H_2O_2 System

在缓冲溶液中,Fenton体系产生的羟基自由基能迅速与五甲川菁染料(Cy5)作用使其褪色,在647 nm处测定体系吸光度的变化,可间接测定羟基自由基的生成量。抗氧化剂的加入可部分消除溶液中的羟基自由基,从而使溶液的吸光度下降程度减弱。据此建立了一种测定抗氧化剂对羟基自由基清除率的新方法。利用所建立的方法测试了抗氧化剂2,6-二叔丁基对甲基苯酚以及几种天然抗氧化剂的抗氧化活性,得到了满意的结果。该方法操作简便、稳定性好,可以作为一种简便的筛选抗氧化剂的方法。

In Tris-HCl buffer solution, the hydroxyl radical （·OH） produced by Fenton system could change the color intensity of pentamethine cyanine dye （CyS）. The change in absorbance was measured at λ=647 nm, and the ·OH produced could be determined indirectly. Based on this principle, a new method was developed to determine the scavenging effect of hydroxyl radical for antioxidant. Meanwhile, the resistance capability of several synthetical and natural antioxidants to hydroxyl radical was measured with satisfactory results. This system can be used as a convenient method for the screening of antioxidants.