Phthalimide Derivatives as Anti-Inflammatory Agents: In Silico COX-2 Targeting and In Vitro Inhibition of PGE2 Production.

Background/

Objectives

The development of specific inhibitors for cyclooxygenase-2 (COX-2) is a challenge for public health. A series of 17 N-phthalimide hybrids was evaluated using a functional M06 meta-GGA hybrid in combination with a polarized 6-311G (d, p) basis set. The top three candidates (6, 10, and 17) were synthesized and evaluated as selective COX-2 inhibitors of PGE-2 using an integrated in silico-in vitro approach.

Methods

Molecular docking against COX-2 (PDB 5KIR) and COX-1 (PDB 6Y3C), supported by homology modeling and DFT geometry optimization (B3LYP/6-31G*), revealed that the phthalimide carbonyl groups and the 3,4,5-trimethoxyphenyl or geranyl-derived moieties establish key hydrogen bonds and hydrophobic contacts with Arg120, Tyr355, Tyr385, and Ser530 in the COX-2 active site, conferring predicted selectivity ΔGCOX-2 vs. COX-1 = -1.4 to -2.8 kcal/mol.

Results

The compounds complied with Lipinski's and Veber's rules and displayed favorable ADMET profiles. In vitro assessment in LPS-stimulated J774A.1 murine macrophages confirmed potent inhibition of PGE2 production, 3.05 µg/mL, with compound 17 exhibiting the highest efficacy, 97.79 ± 5.02% inhibition at 50 µg/mL, and 10 showing 95.22 ± 6.03% inhibition at 50 µg/mL. Notably, all derivatives maintained >90% cell viability up to 250 µg/mL by resazurin assay and showed no evidence of cytotoxicity or mitosis potential in the tests at 24 h.

Conclusions

These results demonstrate that strategic hybridization of phthalimide with natural and synthetic product-derived fragments yields highly potential PGE2 inhibitors. Therefore, compounds 6, 10, and 17 are promising lead candidates for the development of safer anti-inflammatory agents.