Design, Synthesis, and In Vitro Enzymatic Evaluation of Novel Flavone Derivatives as Dual COX-2/5-LOX Inhibitors...

The development of new anti-inflammatory agents with improved safety and efficacy remains a major therapeutic challenge, particularly in light of the adverse effects associated with conventional nonsteroidal anti-inflammatory drugs. In this study, a series of new flavone derivatives were synthesized and evaluated for their inhibitory activities against Cyclooxygenase-1 (COX-1), Cyclooxygenase-2 (COX-2), and 5-Lipooxygenase (5-LOX) through combined in vitro and in silico approaches. Biological screening demonstrated that several derivatives exhibited moderate to strong inhibitory activity across the three enzymes, with IC₅₀ values ranging from 35.67 ± 2.92 to 1137.44 ± 371.05µM. Among these, compounds 5a and 5b emerged as the most promising dual COX-2/5-LOX inhibitors, displaying potent activity toward both targets while maintaining limited COX-1 inhibition, as reflected by their favorable selectivity indices (SI = 2.09 and 5.21, respectively). Molecular docking studies supported the experimental findings, revealing favorable binding affinities of compounds 5a and 5b within the COX-2 active site (PDB: 1CX2), while the flavone-tetrazole hybrid 6b exhibited the highest binding affinity toward the 5-LOX active site (PDB: 6N2W), consistent with its notable inhibitory activity. In silico ADME and toxicity predictions further suggested that the selected derivatives (4a-b, 5a-b, and 6a-b) possess acceptable physiochemical properties, low predicted toxicity, and favorable drug-likeness. Overall, this study identifies flavone-based scaffolds as a promising early-stage lead for the development of dual COX-2/5-LOX inhibitors and provides a rational basis for the design of safer anti-inflammatory agents.