Synthesis of new selective agents with dual anti-inflammatory and SARS-CoV-2 Mpro inhibitory activity: Antipyrine-celecoxib hybrid analogues; COX-2, COVID-19 cytokine storm and replication inhibitory activities.

Herein, a great aim to introduce novel pyrazolone derivatives with multiple activities, including selective COX-2 and cytokine inhibition in addition to SARS-CoV-2 M^pro inhibitory effects. All the synthesized compounds 4a-c, 5, 6a,b, 7a-f, 8a,b, 9a,b, 10a,b and 11a-f were evaluated in vitro for investigation of selective COX-2 inhibitory activity. The results introduced the most selective compounds 7a, 7d, 7e, 9a, and 11f that were further screened in vivo to evaluate their anti-inflammatory activity, safety concerning gastric ulcer and myocardial infarction. Compounds 7e, 9a and 11f exhibited % edema inhibition (43.87-54.31) compared to celecoxib (54.17%17 %) at the same time. Histopathological examination of gastric and cardiac tissues proved the safe profiles of compounds 7e and 11 f. The reduction in cardiac biomarkers level (CK-MP, AST, LDH) and the pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β) ensured the cardiac safety of 7e and 11f. Also, RT-PCR results confirmed the efficacy of compounds 7e and 11f to inhibit gene expression of cytokines responsible for the overwhelming inflammation in COVID-19 infection, including TNF-α, IL-6, IL-2 and IL-1β. Additionally, SARS-CoV-2 M^pro inhibitory assay revealed the potency of the compound 7e against M^pro enzyme (IC₅₀ = 13.24 μM). Furthermore, the proper fitting of 7e inside both COX-2 and M^pro active site through the docking study supported the affinity of 7e to inhibit both enzymes. Therefore, a belief stated that compound 7e is a promising lead compound with a safe profile, acting as a selective COX-2 and cytokine inhibitor. Also, 7e reduces the COVID-19 infection's cytokine storm and inhibits viral replication via targeting the M^pro enzyme.