白桦酯醇的氧化动力学性质及含量分析  

Kinetics of oxidation and analysis of betulin

作　　者：孙宏[1] 张泽[2] 陈艳春[2] 王新颖[1] 

机构地区：[1]齐齐哈尔大学化学化工学院,齐齐哈尔161006 [2]齐齐哈尔市环境监测中心,齐齐哈尔161005

出　　处：《药物分析杂志》2011年第1期154-156,共3页Chinese Journal of Pharmaceutical Analysis

基　　金：黑龙江省科技厅科技攻关计划(GC07C205);齐齐哈尔市工业攻关项目(40736)

摘　　要：目的：测定白桦酯醇清除羟自由基的能力以研究白桦酯醇的氧化动力学性质及其含量分析。方法：根据I3-与罗丹明B（λm ax=556 nm）形成离子缔合物,使体系的吸收峰降低。而白桦酯醇能与羟自由基反应,从而抑制了I3-的生成,使得556 nm处吸光度上升,吸光度的变化与白桦酯醇的浓度相关。结果：白桦酯醇浓度在0~30.94μg.mL-1范围内符合比耳定律,相关系数为0.9991,回收率为98.9%（n=6）,RSD为2.1%。该法适合测定白桦酯醇含量。白桦酯醇的氧化反应为一级反应,其表观活化能为84.25 kJ.mol-1,反应速率常数为3.3×10-3m in-1。它可用作潜在的天然抗氧剂。Objective：To study the oxidation kinetics of betulin and its content a method of determinating hydroxy radical-scavenging capacity of betulin from the birch bark is used.Methods：It is based on the inhibiting effect of betulin on the oxidation of hydroxy radical and gives reliable results,with the monitoring of the decrease of absorbance of Rhodamine B（RB）at a wavelengh of 556 nm.Results：Beer′s law was obeyed in the range of 0-30.94 μg·mL-1,the related coefficient was 0.9991.The recovery was 98.9%（n=6）.The relative standard deviation is 2.1%.Based on this fact,the betulin in betula is measured with satisfactory results.The result shows betulin oxidation kinetics follows the first order reaction.Its apparent activation energy and the reaction rate constant is 84.25 kJ·mol-1 and 3.3×10-3 min-1,respectively.It might be used as a potential source of natural antioxidant agent.

关 键 词：白桦酯醇 羟自由基 动力学 分光光度法 

分 类 号：R917[医药卫生—药物分析学]