Introduction: Nitric oxide (NO) is an important mediator in the pathogenesis and control of immune system-related disorders and its levels are modulated by inducible NO synthase (iNOS). Oxidative stress is another pathological indication in majority of autoimmune disorders. The present study aims at the development of coupled molecules via selection of pharmacophores for both immunomodulatory and antioxidant activities through iNOS inhibition.

Methods: Variedly substituted coumarin moieties are coupled with naturally occurring phenols through an amide linkage and were predicted for activities using computer-based program PASS. The compounds predicted to have dual activities were synthesized. Docking studies were carried out against iNOS (PDB 1R35) and compounds having good docking score were evaluated for immunomodulatory and antioxidant activities.

Results: The synthesized compounds were found to be pure and were obtained in good yields. Compounds with maximum docking score (YR1a, YR2e, YR2c and YR4e) were selected for evaluation by in vitro models. Compounds YR2e and YR2c markedly inhibited the reduction of NBT dye and showed maximum % iNOS inhibition. In DPPH assay, compound YR4e was observed as the most potent antioxidant (EC50 0.33 µM/mL). Based on these studies, compounds YR2e and YR2c were selected for haemagglutination test. Compound YR2e was observed as the most active immunosuppressant with maximal inhibitory ability of iNOS and NBT reduction and lower HAT value of 3.5.

Conclusion: Compound YR2e can be utilized as a pharmacological agent in the prevention or treatment of immunomodulatory diseases such as tumors, rheumatoid arthritis, ulcerative colitis, organ transplant and other autoimmune disorders.

简介：一氧化氮（NO）是免疫系统相关疾病的发病机制和控制中的重要介体，其水平受诱导型NO合酶（iNOS）调节。氧化应激是大多数自身免疫性疾病的另一个病理指标。本研究旨在通过选择通过iNOS抑制而具有免疫调节和抗氧化活性的药效基团来开发偶联分子。

方法：各种取代的香豆素部分通过酰胺键与天然酚结合，并使用基于计算机的程序PASS预测其活性。合成了具有双重活性的化合物。针对iNOS（PDB 1R35）进行了对接研究，并对具有良好对接得分的化合物的免疫调节和抗氧化活性进行了评估。

结果：发现合成的化合物是纯净的，并以良好的收率获得。选择具有最大对接得分的化合物（YR1a，YR2e，YR2c和YR4e）进行体外模型评估。化合物YR2e和YR2c显着抑制NBT染料的还原，并显示出最大的iNOS抑制％。在DPPH分析中，发现化合物YR4e是最有效的抗氧化剂（EC50 0.33 µM / mL）。基于这些研究，选择化合物YR2e和YR2c进行血凝试验。观察到化合物YR2e是最活跃的免疫抑制剂，具有最大的iNOS和NBT抑制抑制能力，并且HAT值较低，为3.5。

结论：化合物YR2e可作为预防或治疗免疫调节性疾病的药物，例如肿瘤，类风湿性关节炎，溃疡性结肠炎，器官移植和其他自身免疫性疾病。