丹参酮ⅡA的化学稳定性研究

Study on the Chemical Stability of Tanshinone ⅡA

目的:利用化学动力学原理,定量考察了丹参药材中的主要活性成分丹参酮ⅡA在不同条件下的反应速率常数及化学动力学模型与方程,探讨了影响丹参酮ⅡA化学稳定性的主要因素。方法:本实验采用化学动力学原理及方法,以ln(Ct/C0)为纵坐标,时间为横坐标绘制丹参酮ⅡA的反应动力曲线,并得到动力学方程。其中反应动力曲线的斜率即为丹参酮ⅡA在该条件下的化学动力学速率常数K,可根据t1/2=0.692/K计算丹参酮ⅡA的半衰期。结果:溶液的pH基本对丹参酮IIA的稳定性无影响。在高温(90℃)加热和光照的作用下丹参酮ⅡA会发生降解反应,其化学动力学反应为一级反应,根据阿累尼乌斯经验公式计算得到丹参酮ⅡA的活化能为82.74 kJ/mol。结论:丹参酮ⅡA在高温和光照条件下不稳定,容易发生降解反应,此可能为丹参制剂的提取、浓缩、制粒、干燥及成品的全过程中,丹参酮ⅡA含量降低的主要原因。

Objective：To investigate the chemical kinetics of tanshinone ⅡA in different conditions quantitatively and calculate the chemical kinetic parameters and equations in order to find out the major factors affecting the stability of tanshinone ⅡA.Methods：The kinetic line was obtained by setting the ln（Ct/C0） as ordinate and making time as abscissa.The slope of the kinetic line was the reaction constant of tanshinone ⅡA in such condition.The t1/2 was calculated by the equation t1/2=0.692/K.Results：The influences of initial concentration,pH value,temperature and light on stability of tanshinone ⅡA in solutions were carried out,respectively.The results suggested the degradation of tanshinone ⅡA in solutions fitted the pseudo-first-order reaction.The chemical kinetics parameters including rates constant and half time of degradation in different conditions were obtained by the means of ln（Ct/C0） versus reaction time.The activation energy of tanshinone ⅡA in solutions were also available from the calculation of rate constants under different temperature according to the Arrhenius equation and was 82.74 kJ/mol.Conclusion：Tanshinone ⅡA is unstable in the high temperature and light conditions,and is prone to degradation,this may be the main reason for its decrease in the whole process of extraction,concentration,granulation,drying and ending product of Danshen prescription.