School of Pharmacy, China Medical University, 77 Puhe Road, North New Area, Shenyang 110122, China.
School of Pharmacy, China Medical University, 77 Puhe Road, North New Area, Shenyang 110122, China.
Bioorg Chem. 2021 Dec;117:105417. doi: 10.1016/j.bioorg.2021.105417. Epub 2021 Oct 9.
Our previous work identified a promising isonicotinamide based xanthine oxidase (XO) inhibitor, N-(3-cyano-4-((2-cyanobenzyl)oxy)phenyl)isonicotinamide (1), and concluded that amide is an effective linker in exploring the XO inhibitor chemical space that is completely different from the five-membered ring framework of febuxostat and topiroxostat. Indole, an endogenous bioactive substance and a popular drug construction fragment, was involved in the structural optimization campaign of the present effort. After the installation of some functional groups, N-(1-alkyl-3-cyano-1H-indol-5-yl) was generated and employed to mend the missing H-bond interaction between the 3'-cyano of 1 and Asn768 residue of XO by shortening their distance. In this context, eight kinds of heterocyclic aromatic amide chemotypes were rationally designed and synthesized to investigate the structure-activity relationship (SAR) of amide-based XO inhibitors. The optimized compound a6 (IC = 0.018 μM) exhibits 17.2-fold improved potency than the initial compound 1 (IC = 0.31 μM). Its potency is comparable to that of topiroxostat (IC = 0.013 μM). Molecular docking and molecular dynamics studies proved the existence of the stable H-bond between the cyano group and the Asn768 residue. Moreover, oral administration of a6 (11.8 mg/kg) could effectively reduce serum uric acid levels in an acute hyperuricemia rat model. Liver microsomal stability assay illustrated that compound a6 possesses well metabolic stability in rat liver microsomes. However, the in vivo potency of a6 was much lower than that of topiroxostat, which may be explained by the poor absorption found in the parallel artificial membrane permeability assay (PAMPA). In addition, 6a has non-cytotoxicity against normal cell lines MCF10A and 16HBE. Taken together, this work culminated in the identification of compound 6a as an excellent lead for further exploration of amide-based XO inhibitors.
我们之前的工作确定了一种有前途的异烟酰胺类黄嘌呤氧化酶（XO）抑制剂，N-(3-氰基-4-((2-氰基苄基)氧基)苯基)异烟酰胺（1），并得出结论酰胺是探索与非布司他和托匹司他的五元环骨架完全不同的 XO 抑制剂化学空间的有效连接基。吲哚，一种内源性生物活性物质和流行的药物结构片段，参与了本研究的结构优化。在安装了一些官能团后，生成了 N-(1-烷基-3-氰基-1H-吲哚-5-基)，并用其缩短与 XO 的 Asn768 残基的 3'-氰基之间的距离，修复缺失的氢键相互作用。在这种情况下，合理设计并合成了八种杂环芳酰胺类化合物，以研究酰胺类 XO 抑制剂的构效关系（SAR）。优化后的化合物 a6（IC = 0.018 μM）的活性比初始化合物 1（IC = 0.31 μM）提高了 17.2 倍。其活性可与托匹司他（IC = 0.013 μM）相媲美。分子对接和分子动力学研究证明了氰基和 Asn768 残基之间存在稳定的氢键。此外，a6（11.8 mg/kg）口服给药可有效降低急性高尿酸血症大鼠模型中的血清尿酸水平。肝微粒体稳定性试验表明，化合物 a6 在大鼠肝微粒体中具有良好的代谢稳定性。然而，a6 的体内活性远低于托匹司他，这可能是由于在平行人工膜渗透率测定（PAMPA）中发现的吸收不良所致。此外，6a 对正常细胞系 MCF10A 和 16HBE 无细胞毒性。总之，这项工作确定了化合物 6a 作为进一步探索酰胺类 XO 抑制剂的优秀先导化合物。
