罗丹明6G-锰A-过氧化氢体系荧光法测定常见油性种子的抗氧化活性

Determination of Antioxidant Activity in Several Kinds of Oil Seed by Fluorimetry with Rhodamine 6G-Mn^(2+)-H_2O_2 System

碱性介质中罗丹明 6G能产生特征荧光 ,其最大激发波长和发射波长分别为 35 0nm和 5 5 0nm ;Mn2 + H2 O2 体系在碱性介质中产生的羟自由基可以迅速氧化罗丹明 6G使其荧光猝灭 ,而油性种子的浸提物可以清除羟自由基 ,从而使溶液的荧光猝灭程度降低 ,据此建立了测定油性种子抗氧化性的新方法。实验观察到 :抗氧化剂维生素C和硫脲等在低浓度范围内对羟自由基的清除率与用量呈上升关系 ,而在大浓度下反而下降。讨论了样品的水、醋酸、乙醇溶剂浸提物对羟自由基的清除效率。用水、醋酸作提取剂 ,分别测试了7种常见油性种子的抗氧化活性。

Rhodamine 6G (Rh 6G) produces characteristic fluorescence at excitation and emission wavelength of 350 nm and 550 nm in basic solution, respectively. It is oxidized by hydroxyl radical rapidly and the fluorescence is quenched. Extractives of oil seed may eliminate hydroxyl radical in solution, and then decreases the quenching effect. Based on this principle, a new method was developed to determine the eliminating ratio of oil seed for hydroxyl radical. It was found that when antioxidants concentration is low, scavenging percentage would be increased with the amount of antioxidants. When antioxidants concentration is high, scavenging percentage would be decreased with the amount of antioxidants. The results showed that the order of hydroxyl radical scavenging capacities was ethanol-sol. fraction>vinegar-sol. fraction>water-sol. fraction. The antioxidative activity of 7 kinds of oil seed in water and vinegar was determined.