次甲基蓝-Mn^(2+)-H_2O_2体系光度法测定中药的抗氧化性  

Spectrophotometric Determination of Antioxidant Activity of Chinese Traditional Medicine with Methylene Blue-Mn^(2+)-H_2O_2 System

作　　者：张爱梅[1] 李林尉[1] 郝贵奇[1] 刘永刚[1] 

机构地区：[1]聊城大学化学化工学院,山东聊城252059

出　　处：《分析测试学报》2005年第4期83-85,共3页Journal of Instrumental Analysis

摘　　要：提出了Mn2+-H2O2-次甲基蓝分析新体系并用于羟自由基的测定。醋酸介质中,用Mn2+与H2O2反应,类似Fenton试剂产生羟自由基,羟自由基与次甲基蓝反应,使次甲基蓝褪色,用分光光度计测定其吸光度的变化(ΔA664),可间接测定羟自由基的产生量。实验结果表明,ΔA664与次甲基蓝、MnSO4及H2O2呈量效关系。中药提取物可以清除溶液中的羟自由基,使次甲基蓝溶液的褪色程度降低,据此建立了一种测定中药对羟自由基清除率的新方法。测定了五倍子、诃子、金银花等11种中药的抗氧化性,结果满意。An indirect spectrophotometric determination of hydroxyl radical(·OH)with a new system of methylene blue-Mn 2+ -H 2 O 2 is reported.It is based on the fact that methylene blue can be decolorized by the·OH produced via the reaction of Mn 2+ with H 2 O 2 in acetic acid medium.It is found that the change in absorbance at a wavelength of664nm(ΔA 664 ),is related quantitatively with the amount of methylene blue and the reactants H 2 O 2 and MnSO 4 .It has been shown that the Chinese traditional medicines can scavenge the·OH,minimizing the decolorizing of methylene blue.Thus the developed method can be applied to the determination of antioxidant activities of Chinese traditional medicines.The·OH percent scavenged by the aqueous extracts of11kinds ofthe Chinese traditional medicines were determined.The results showed thatscav-enging percent of·OH of the medicines varied from each other,Myrabolam has the highest scavenging per-cent(77.4%),whereas Scullcap has the lowest percent(11.4%).

关 键 词：分光光度法 羟自由基 次甲基蓝 清除率 中药 

分 类 号：O657.32[理学—分析化学]