Revisiting COX-2 inhibitors for Alzheimer's disease as multitargeted ligands: Development of 4-hydrazono-pyrazolidinediones with tuned COX selectivity profile and improved cellular potency.

Herein, we expand on our previously synthesized 4-hydrazono-pyrazolidinedione COX-2 inhibitors as multitargeted agents for Alzheimer's disease (AD). Structural modifications of the 4-phenylhydrazono group led to the identification of several highly potent COX-2 inhibitors, with compound 3 exhibiting the strongest COX-2 inhibition (IC50 = 0.07 μM), with a balanced COX-2/COX-1 profile, suggesting lower cardiovascular risk. Compounds 2 and 9 showed high potency and selectivity shift toward COX-1 and displayed strong antiplatelet activity. Several derivatives showed 4-7 times improved submicromolar cellular potency, significantly inhibiting PGE2 release in LPS-stimulated THP-1 cells. Compounds 2, 3, 7, and 9 maintained the multitarget profile and inhibited Aβ and tau aggregation. Compounds 2, 3, and 7 protected against Amyloid-beta (Aβ)- and H2O2-induced cytotoxicity, confirming their neuroprotective activity with high potential for BBB permeability demonstrated via PAMPA and MDCK-MDR1 assays. These results support the potential of multitargeted COX-2 inhibitors as AD therapeutics and suggest a re-evaluation of their role in neurodegenerative disease treatment.