Synthesis and Evaluation of NF-κB Inhibitory Activity of Mollugin Derivatives

(1) Background: Nuclear factor κB (NF-κB) is an important transcriptional regulator that regulates the inflammatory pathway and plays a key role in cellular inflammatory and immune responses. The presence of a high concentration of NF-κB is positively correlated with the severity of inflammation. Therefore, the inhibition of this pathway is an important therapeutic target for the treatment of various types of inflammation; (2) Methods: we designed and synthesized 23 mollugin derivatives and evaluated their inhibitory activity against NF-κB transcription; (3) Results: Compound 6d exhibited the most promising inhibitory activity (IC₅₀ = 3.81 µM) and did not show any significant cytotoxicity against the tested cell lines. Investigation of the mechanism of action indicated that 6d down-regulated NF-κB expression, possibly by suppressing TNF-α-induced expression of the p65 protein. Most of the compounds exhibited potent anti-inflammatory activity. Compound 4f was the most potent compound with 83.08% inhibition of inflammation after intraperitoneal administration, which was more potent than mollugin and the reference drugs (ibuprofen and mesalazine). ADMET prediction analysis indicated that compounds 6d and 4f had good pharmacokinetics and drug-like behavior; (4) Conclusions: Several series of mollugin derivatives were designed, synthesized, and evaluated for NF-κB inhibitory activity and toxicity. These results provide an initial basis for the development of 4f and 6d as potential anti-inflammatory agents.