Tailored [1,2,4]triazolo[1,5-a]pyrimidine hybrids as promising anti-inflammatory agents with COX/5-LOX/ROS/IL-6 multifunctional inhibitory activity: design, synthesis, SAR, and in silico study.

To develop potent anti-inflammatory agents with safer profiles, a hybridization approach combining [1,2,4]triazolo[1,5-a]pyrimidine/chalcone (5a-g) and [1,2,4]triazolo[1,5-a]pyrimidine/pyrazole (6a-g) has been rationally designed to synthesize potential COX/5-LOX/ROS/IL-6 multifunctional inhibitors. All synthesized hybrids were evaluated in vitro using biological COX-1/COX-2 assays. Compounds 5a, 6c, and 6d displayed the highest COX-2 potency and selectivity (5a; IC50 = 1.361 µM, SI = 12.86, 6c; IC50 = 2.537 µM, SI = 18.05, and 6d; IC50 = 1.237 µM, SI = 8.917), outperforming the reference diclofenac sodium (IC50 = 4.812 µM, SI = 2.552). These promising derivatives were selected for further in vitro assays to evaluate their inhibitory effects on 5-LOX, ROS, and IL-6. The most potent COX-2 inhibitor 6d exhibited reasonable 5-LOX inhibitory activity (IC50 = 1.031 µM) in comparison to the selective 5-LOX inhibitor zileuton (IC50 = 0.386 µM). Moreover, 6d exhibited potent inhibitory activity against the proinflammatory cytokine IL-6 (90.9% inhibition) and ROS scavenging activity (IC50 = 34.45 µM), exceeding the two references, celecoxib and diclofenac sodium. Furthermore, compound 6c displayed substantial inhibition of TNF-α release (69.44%), approaching that of the reference drug diclofenac sodium (75.75%). Ultimately, docking simulations and drug-likeness studies provided insights into the potential binding scenarios within the active sites of COX-2 and 5-LOX, while also predicting the oral bioavailability and toxicity of the newly synthesized compounds. Based on these findings, the designed scaffolds can be considered as promising multitargeted anti-inflammatory candidates worthy of further exploration.