Tang You-Zhi, Liu Zai-Qun
Department of Organic Chemistry, College of Chemistry, Jilin University, Changchun 130021, China.
J Pharm Pharmacol. 2006 May;58(5):625-31. doi: 10.1211/jpp.58.5.0007.
Free-radical-induced peroxidation in-vivo is regarded as the aetiology of some diseases and free-radical-scavenging drugs, also called antioxidants (AH), have been widely used to overcome oxidative stress. An in-vitro experimental method, 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH)-induced haemolysis of human erythrocytes can be applied to assess the free-radical-scavenging activity of a drug. The major objectives of this work were focused on three aspects. Firstly, introduction of the chemical kinetic deduction of free-radical-initiating reaction to AAPH-induced haemolysis of human erythrocytes, by which the number of free radicals trapped by an antioxidant, n, can be obtained after finding the quantitative relationship between the inhibition period (t(inh)) and the concentration of the antioxidant, t(inh) = (n/Ri) [AH]. Ri, the free-radical-initiating rate, was initially confirmed by using alpha-tocopherol (VE) whose n was taken as 2. Secondly, the free-radical-scavenging activity of diclofenac acid (DaH) and its sodium salt (DaNaH) was assessed. It has been found that DaH and DaNaH protect human erythrocytes against AAPH-induced haemolysis dose-dependently. In particular, the n values of DaH and DaNaH (4.96 and 3.60) were much higher than some traditional antioxidants, such as 6-hydroxyl-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox, a water-soluble structural analogue of VE, n = 0.30) and L-ascorbic acid (VC, n = 0.25), and L-ascorbyl-6-laurate (VC-12, a lipophilic structural analogue of VC, n = 1.11). Moreover, the free-radical-scavenging activity of lipophilic antioxidants is higher than the corresponding water-soluble species. Thirdly, the free-radical-scavenging activity of mixed antioxidants, VE + DaH, VC-12 + DaH, Trolox + DaNaH and VC + DaNaH, was revealed. The n value of VC, VC-12, VE and Trolox increase in the case of mixed usage with DaH and DaNaH, implying that diclofenac acid can repair the radical of these antioxidants. Thus, a mutual antioxidant effect between diclofenac acid and these antioxidants prolongs the lifespan of VC, VC-12, VE and Trolox, respectively.
体内自由基诱导的过氧化作用被认为是某些疾病的病因，自由基清除药物，也称为抗氧化剂（AH），已被广泛用于克服氧化应激。一种体外实验方法，即2,2'-偶氮二（2-脒基丙烷盐酸盐）（AAPH）诱导的人红细胞溶血，可用于评估药物的自由基清除活性。这项工作的主要目标集中在三个方面。首先，将自由基引发反应的化学动力学推导引入到AAPH诱导的人红细胞溶血中，通过该方法，在找到抑制期（t(inh)）与抗氧化剂浓度之间的定量关系t(inh) = (n/Ri) [AH]后，可以得到被抗氧化剂捕获的自由基数量n。自由基引发速率Ri最初通过使用α-生育酚（VE）得到确认，其n值取为2。其次，评估了双氯芬酸（DaH）及其钠盐（DaNaH）的自由基清除活性。已发现DaH和DaNaH能剂量依赖性地保护人红细胞免受AAPH诱导的溶血。特别是，DaH和DaNaH的n值（4.96和3.60）远高于一些传统抗氧化剂，如6-羟基-2,5,7,8-四甲基色满-2-羧酸（Trolox，VE的水溶性结构类似物，n = 0.30）、L-抗坏血酸（VC，n = 0.25）和L-抗坏血酸-6-月桂酸酯（VC-12，VC的亲脂性结构类似物，n =
