Discovery of Novel 5-Substituted-4-Allyl-1,2,4-Triazoles as Potential Nonsteroidal Anti-Inflammatory Agents via Downregulation of iNOS Expression.

Inducible nitric oxide synthase (iNOS) is a key mediator of inflammatory signaling, and excessive iNOS-derived nitric oxide (NO) contributes to the pathology of multiple chronic inflammatory disorders. Herein, we report the design and synthesis of a focused series of 5-substituted 4-allyl-1,2,4-triazole-3-thiol derivatives (7a-f) bearing an acetanilide fragment, targeting suppression of iNOS-driven NO production. In lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages, several analogues attenuated nitrite accumulation, with compound 7c emerging as the most active member of the series (80% inhibition at 100 μM; IC₅₀ = 12.91 μM). Mechanistically, 7c downregulated iNOS protein expression in a concentration-dependent manner, consistent with its NO-suppressing phenotype. In vivo, compound 7c significantly reduced L-arginine-potentiated carrageenan paw edema, decreased paw nitrite levels, improved histopathological inflammatory features, and displayed lower ulcerogenic liability than indomethacin at the tested conditions. Collectively, these findings identify allyl-1,2,4-triazoles as a promising scaffold for developing next-generation anti-inflammatory agents acting through iNOS downregulation.