Elucidating the Structure-Activity Relationships of the Vasorelaxation and Antioxidation Properties of Thionicotinic Acid Derivatives
作者:Supaluk Prachayasittikul、Orapin Wongsawatkul、Apilak Worachartcheewan、Chanin Nantasenamat、Somsak Ruchirawat、Virapong Prachayasittikul
DOI:10.3390/molecules15010198
日期:——
Nicotinic acid, known as vitamin B3, is an effective lipid lowering drug and intense cutaneous vasodilator. This study reports the effect of 2-(1-adamantylthio)nicotinic acid (6) and its amide 7 and nitrile analog 8 on phenylephrine-induced contraction of rat thoracic aorta as well as antioxidative activity. It was found that the tested thionicotinic acid analogs 6-8 exerted maximal vasorelaxation in a dose-dependent manner, but their effects were less than acetylcholine (ACh)-induced nitric oxide (NO) vasorelaxation. The vasorelaxations were reduced, apparently, in both NG-nitro-L-arginine methyl ester (L-NAME) and indomethacin (INDO). Synergistic effects were observed in the presence of L-NAME plus INDO, leading to loss of vasorelaxation of both the ACh and the tested nicotinic acids. Complete loss of the vasorelaxation was noted under removal of endothelial cells. This infers that the vasorelaxations are mediated partially by endothelium-induced NO and prostacyclin. The thionicotinic acid analogs all exhibited antioxidant properties in both 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide dismutase (SOD) assays. Significantly, the thionicotinic acid 6 is the most potent vasorelaxant with ED50 of 21.3 nM and is the most potent antioxidant (as discerned from DPPH assay). Molecular modeling was also used to provide mechanistic insights into the vasorelaxant and antioxidative activities. The findings reveal that the thionicotinic acid analogs are a novel class of vasorelaxant and antioxidant compounds which have potential to be further developed as promising therapeutics.
烟酸被称为维生素 B3,是一种有效的降血脂药物和强效的皮肤血管扩张剂。本研究报告了 2-(1-金刚烷硫基)烟酸(6)及其酰胺 7 和腈类似物 8 对苯肾上腺素诱导的大鼠胸主动脉收缩的影响以及抗氧化活性。研究发现,受试的硫代烟酸类似物 6-8 以剂量依赖的方式发挥了最大的血管舒张作用,但其效果低于乙酰胆碱(ACh)诱导的一氧化氮(NO)血管舒张作用。在 NG-硝基-L-精氨酸甲酯(L-NAME)和吲哚美辛(INDO)的作用下,血管舒张明显减弱。在 L-NAME 和 INDO 的作用下,观察到了协同效应,导致 ACh 和测试的烟酸都失去了舒张血管的作用。移除内皮细胞后,血管舒张作用完全消失。这说明血管舒张部分是由内皮诱导的 NO 和前列环素介导的。在 2,2-二苯基-1-苦基肼(DPPH)和超氧化物歧化酶(SOD)试验中,硫代烟酸类似物都表现出抗氧化特性。值得注意的是,硫代烟酸 6 是最有效的血管舒张剂,ED50 为 21.3 nM,也是最有效的抗氧化剂(从 DPPH 试验中可以看出)。此外,还利用分子建模对血管舒张和抗氧化活性进行了机理分析。研究结果表明,硫代烟酸类似物是一类新型的血管舒张和抗氧化化合物,有潜力进一步开发成为有前途的治疗药物。