化学学报 ›› 2001, Vol. 59 ›› Issue (7): 1015-1020. 上一篇    下一篇

研究论文

氢化可的松催化超氧阴离子歧化及反应动力学

邵勇;过玮;宋俊峰   

  1. 西北大学分析科学研究所
  • 发布日期:2001-07-15

Dismutation of superoxide anion catalyzed by hydrocortisone and its reaction kinetics

Shao Yong;Guo Wei;Song Junfeng   

  • Published:2001-07-15

在0.1mol·L^-1NaHCO3介质中,用伏安法研究了超氧阴离子O2^.-与糖皮质类甾体氢化可的松的化学反应。实验表明,氢化可的松清除O2^.-的化学作用机制为氢化可的松催化O2^.-的歧化反应,氢化可的松是O2^.-的清除剂。氢化可的松催化O2^.-歧化反应的速率对O2^.-为零级表观反应,对氢化可的松则为二级表观反应,求得20℃时氢化可的松催化O2^.-歧化反应表观速率常数k为8.76×10^5L·mol^-1·s^-1。本结果为医学组织研究结果提供了新的实验证据。在抗炎作用方面,氢化可的松除抑制磷脂酶A2的活性从而间接阻止O2^.-的产生外,还能直接化学清除产生的O2^.-,认为氢化可的松的抗炎作用应是这种生物和化学的综合作用结果。

关键词: 氢化可的松, 表观, 伏安法, 糖皮质激素, 超氧阴离子, 歧化反应, 反应动力学, 自由基清除

In o.1 mol·L^-1 NaHCO3 medium, the chemical reaction of hydrocortisone with superoxide anion O2^.- is studied by voltammetry. Experimental results prove that hydrocortisone, as a scavenger of O2^. -, can catalyze the dismutation reaction of O2^.-. The apparent reaction progression of the catalytic dismutation is zero for O2^.-, but two for hydrocortisone. The equation of rate constant for the catalytic dismutation reaction is deduced, and the apparent rate constant obtained is 8.76×10^5L·mol^-1·s^-1. The result obtained gives new evidence for biomedical research. Besides the indirect inhibition of O2^.- generation by such synthesized glucocorticoids as hydrocortisone suppressing the activity ofphospholipase A2, chemically hydrocortisone can also directly scavenge O2^.- produced. Therefore, the activity of hydrocortisone as an anti - inflammatory drug is ascribed to the combination of its biologic effectiveness and chemical scavenging for O2^.-.

Key words: HYDROCORTISONE, APPARENT, VOLTAMMETRY, GLUCOCORTICOID, DISPROPORTIONATION REACTION, REACTION KINETICS, RADICALS SCAVENGING

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