流动注射化学发光法测定茶叶对羟自由基的清除率

Determination of Scavenging Effect of Tea on Hydroxyl Radical by Flow Injection Chemiluminescence Method

建立了Fe2+-H2O2-亚甲基蓝化学发光新体系,并用于茶叶对羟自由基(·OH)清除率的测定。实验发现,在酸性介质中,Fe2+和H2O2在线生成的·OH与亚甲基蓝反应能产生极强的化学发光,茶叶提取液可清除溶液中部分·OH,使化学发光强度降低。据此,结合流动注射技术,建立了测定茶叶对·OH清除率的化学发光新方法。对不同茶类的成茶及苦丁茶和绞股蓝茶清除·OH作用进行了比较研究,结果表明,绿茶对·OH的清除率最高,抗氧化活性最强。

A new chemiluminescence （CL） system was established by mixing methylene blue solution with Fe2＋-H2O2 solution in acidic medium for the determination of scavenging effect of tea on hydroxyl radical. The CL intensity decreased when the extractives of tea were added to the reaction system, indicating that the hydroxyl free radicals（·OH）were scavenged partially in the solution. Based on this principle, a new method was developed to determine the scavenging effect of tea on hydroxyl radical, and the antioxidantive activities of 8 kinds of teas were determined. The results showed that green tea demonstrated the strongest antioxidantive activity.