Investigation of Antioxidative Ability of Nicotinic acid-related Cpmpounds

烟酸相关化合物的新的生理和药物功能是抗氧化能力。然后研究了这些化合物的这种能力。首先用电子自旋共振（ESR）自旋俘获法研究了其清除羟基自由基的能力。结果表明，其对异烟酸、异烟酸酰胺、烟酸肼、异烟酸肼、6-氨基烟酸、6-氨基烟酸酰胺、吡啶等具有较强的吸附能力。其次，研究了这些化合物在细胞系统中的抗氧化能力。即用这些化合物处理HL-60细胞，然后用过氧化氢或过氧化叔丁基（tBHP）给予氧化应激，用双乙酸二氯荧光素（DCFH-DA）作为氧化应激探针，用流式细胞术检测细胞的氧化状态。结果表明，过氧化氢处理后的烟酸肼能有效地降低氧化应激。异烟酸肼在10 mM和1 mM时也有效。因此，可以说，除了在体外，烟酸肼和异烟酸肼在细胞内都是有效的抗氧化剂。由此可见，两种化合物对过氧化氢或三必和二必bhp氧化应激诱导的细胞凋亡有不同的作用。以此为基础，研究了烟酸肼和异烟酸肼对氧化应激诱导的细胞凋亡的影响。结果表明，这些化合物可抑制过氧化氢诱导的细胞凋亡。然而，这些化合物对三必和必拓诱导的细胞凋亡无效。

Novel physiological and pharmaceutical functions of nicotinic acid-related compounds are antioxidative ability. Then this ability of these compounds was searched. At first hydroxy radical scavenging ability was investigated by spin trapping method with electron spin resonance (ESR). As the results, its strong ability was found in isonicotinic acid, isonicotinamide, nicotinic acid hydrazide, isonicotinic acid hydrazide, 6-aminonicotinic acid, 6-aminonicotinamide, pyridine, etc. Secondly, antioxidative ability of these compounds in cell system was investigated. Namely, HL-60 cells were treated with these compounds, then oxidative stress was given with hydrogen peroxide or tert-butylhydroperoxide (tBHP), and oxidative state in the cells was measured with flow cytometry using dichlorofluorescein diacetate (DCFH-DA) as a probe for oxidative stress. As the results, oxidative stress was effectively reduced by nicotinic acid hydrazide after hydrogen peroxide treatment. And isonicotinic acid hydrazide was also effective at 10 mM and 1 mM.Therefore, it can be said that nicotinic acid hydrazide and isonicotinic acid hydrazide were effective as antioxidants in cells in addition to in vitro. From above results different effect were expected among both compounds in apoptosis induced by oxidative stress with hydrogen peroxide or tBHP.Accordingly the effect of nicotinic acid hydrazide and isonicotinic acid hydrazide on the apoptosis induced by oxidative stress was investigated. As the results, the apoptosis induced by hydrogen peroxide was suppressed by these compounds. However, these compounds were not effective for the apoptosis induced by tBHP.