Mn~(2+)-H_2O_2-PAR分光光度法测定羟自由基及抗坏血酸抗氧化活性的比较

提出Mn~(2+)-H_2O_2-PAR4-(2-吡啶偶氮)-间苯二酚]新体系并用于羟自由基的检测。pH 10的硼砂-氢氧化钠缓冲溶液中Mn~(2+)-H_2O_2体系产生羟自由基,加入偶氮染料PAR,羟自由基迅速氧化PAR-Mn~(2+)螯合物分解退色,测定500nm处吸光度的变化确定羟自由基产生的量。利用所建立的实验方法对抗坏血酸清除羟自由基的能力进行测定,其结果与DPPH·(二苯代苦味肼基自由基)分光光度法和羟自由基测定试剂盒法相比。结果表明:该方法稳定性好,操作简便,测定快速,重现性稳定,相对标准偏差为1.42%,可作为一种简便的筛选抗氧化剂的方法。3种方法中抗坏血酸的IC_(50)分别为0.013、0.005、0.2 mg/mL。

Determination of Hydroxyl radical by Spectrophotometry with Mnz+-H2O2-PAR System and Comparative Study on Antioxidant Activity of Ascorbic Acid

A new method of the determination of hydroxyl radical by Mn~(2+)-H_2O_2-PAR has been pro- posed.After being oxidized by hydroxyl radical,PAR-Mn~(2+) showed a color change and the absorbance on 500nm has been decreased,then the quantity of hydroxyl radical can be ascertained.Based on this principle, a new method was developed to determine hydroxyl radical.Besides,the scavenging capability of ascorbic acid on hydroxyl radical was investigated by such method.And the result is compared with DPPH·method and hydroxyl radical reagent kit method.This system used as a convenient method for the selection of antioxidants.The IC_(50) of ascorbic acid in three methods are 0.013 mg/mL,0.005 mg/mL,0.2 mg/mL,respectively.