硫辛酸清除自由基的反应动力学研究

Pulse radiolysis and laser flash photolysis studies on α-lipoic acid

利用脉冲辐解和激光光解瞬态吸收光谱装置,研究了硫辛酸清除活性氧自由基(ROS)的反应机理,获得涉及反应的瞬态吸收光谱和反应速率常数,测得硫辛酸清除.OH,eaq-,CO3.-,SO4.-,Br2.-的反应速率常数分别为7.4×109、1.3×1010、9.8×108、2.3×109、2.0×109L·mol-1·s-1,并对可能的反应机理进行了探讨。结果表明,硫辛酸能有效地清除活性氧自由基,是个高效的抗氧化剂。

In this work the property of α-lipoic acid （LA） was studied by using pulse radiolysis and laser flash photolysis technology. The characteristics and mechanism of the reactions of LA with ROS （reactive oxygen species） were studied. Transient spectra of LA radicals were observed and the transient species with characteristic absorption spectra were identified. It has been found that LA can effectively quench active oxygen radicals such as ＂OH, CO3^-, SO4^-, eaq, Br2 at the rates of 7.4×10^9、1.3×10^10、9.8×10^8、2.3×10^9、2.0×10^9L·mol^-1·s^-1, respectively. The relevant mechanism of the reactions has been discussed. The studies indicate that LA can quench free radicals existing in biological system effectively as a powerful antioxidant.