基于果糖自氧化体系的抗氧化剂筛选方法

机体内果糖的自氧化过程中会产生多种自由基, 并最终转化为羟自由基, 苯甲酸钠可捕获羟自由基生成具有强荧光信号的羟基苯甲酸钠. 本文采用荧光光度法考察了影响果糖自氧化体系的各种因素, 建立了果糖自氧化产生羟自由基体系. 实验结果表明, 在果糖浓度为8.00 mmol/L, CuSO₄浓度为20.0 μmol/L, 苯甲酸钠浓度为24.0 mmol/L, pH=7.4, 温度为37℃及反应时间为24 h的条件下, 果糖自氧化体系最终可产生19.27 μmol/L的羟自由基. 抗氧化剂的存在可清除果糖自氧化过程中产生的自由基, 使最终生成的羟自由基的量减少, 从而导致生成的羟基苯甲酸钠减少, 荧光信号减弱, 由此建立了基于果糖自氧化体系的抗氧化剂筛选方法. 利用本评价体系考察了抗氧化剂盐酸小檗碱和阿魏酸的抗氧化能力, 实验结果表明, 中药标准品盐酸小檗碱和阿魏酸均能有效清除果糖自氧化体系产生的羟自由基, 其IC₅₀值分别为0.023和0.036 mmol/L.

Novel Screening Method for Antioxidants Based on the Fructose Autoxidation

The fructose in organisms can occur autoxidation reaction to produce kinds of free radicals, which transform to hydroxyl radical(·OH) finally. While ·OH can be captured by sodium benzoate to yield salicylate, which has strong fluroscence emission. The effects of fructose autoxidation were investigated and optimized using fluorescence method. A total of 19.27 μmol/L ·OH were produced under the conditions of pH=7.4, 37℃, reaction time 24 h and the concentrations of fructose, CuSO4 and sodium benzoate of 8.00 mmol/L, 20.0 μmol/L and 24.0 mmol/L, respectively. Antioxidants can scavenge free radicals produced by fructose autoxidation, which resulted in less ·OH product. From these process and principle, a novel screening method for antioxidants were developed based on fructrose autoxidation system. The antioxidative capacity of berberine hydrochloride and ferulic acid were estimated using developed method. The antioxidative capacity of berberine hydrochloride is stronger than that of ferulic acid, their IC50 values are 0.023 and 0.036 mmol/L, respectively.