Liu Z Q, Yu W, Liu Z L
National Laboratory of Applied Organic Chemistry, Lanzhou University, Gansu, People's Republic of China.
Chem Phys Lipids. 1999 Dec;103(1-2):125-35. doi: 10.1016/s0009-3084(99)00101-2.
The antioxidative and/or prooxidative activity of 4-methylcoumanrin (MC), 7-hydroxy-4-methylcoumarin (HMC) and 7,8-dihydroxy-4-methylcoumarin (DHMC), respectively, in the peroxidation of human low-density lipoprotein (LDL) has been studied. The peroxidation was initiated either thermally by water-soluble initiator 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH), or photochemically by a triplet sensitizer benzophenone (BP) or its water-soluble analogue disodium 3,3'-disulfobenzophenonate (DSBP). The reaction kinetics were monitored by the uptake of oxygen and the depletion of alpha-tocopherol (TOH) present in the native LDL. Kinetic analysis of the peroxidation process demonstrated that DHMC is a good antioxidant for both the AAPH-initiated and BP- and DSBP-photosensitized peroxidation; HMC is a prooxidant for the AAPH-initiated and DSBP-photosensitized peroxidation, but an antioxidant for the BP-sensitized peroxidation; MC is a prooxidant in all of these initiation conditions. The antioxidative action of the coumarin derivatives may include trapping the initiating radicals, trapping the propagating lipid peroxyl radicals, recycling alpha-tocopherol and/or deactivating the excited photosensitizer.
分别研究了4-甲基香豆素（MC）、7-羟基-4-甲基香豆素（HMC）和7,8-二羟基-4-甲基香豆素（DHMC）在人低密度脂蛋白（LDL）过氧化反应中的抗氧化和/或促氧化活性。过氧化反应通过水溶性引发剂2,2'-偶氮二（2-脒基丙烷盐酸盐）（AAPH）热引发，或通过三重态敏化剂二苯甲酮（BP）或其水溶性类似物3,3'-二磺基二苯甲酮二钠（DSBP）光化学引发。通过监测氧气的吸收和天然LDL中存在的α-生育酚（TOH）的消耗来监测反应动力学。过氧化过程的动力学分析表明，DHMC对AAPH引发的以及BP和DSBP光敏化的过氧化反应都是良好的抗氧化剂；HMC对AAPH引发的和DSBP光敏化的过氧化反应是促氧化剂，但对BP敏化的过氧化反应是抗氧化剂；MC在所有这些引发条件下都是促氧化剂。香豆素衍生物的抗氧化作用可能包括捕获引发自由基、捕获传播的脂质过氧自由基、回收α-生育酚和/或使激发的光敏剂失活。
