Inhibitory effects of triarylpyrazole derivatives on LPS-induced nitric oxide and PGE₂ productions in murine RAW 264.7 macrophages

In this article, a series of 22 triarylpyrazole derivatives were evaluated for in vitro antiinflammatory activity as inhibitors of nitric oxide (NO) and prostaglandin E₂ (PGE₂) release induced by lipopolysaccharide (LPS) in murine RAW 264.7 macrophages. The synthesized compounds 1a-h, 2a-f and 3a-h were first examined for their cytotoxicity for determination of the non-toxic concentration for antiinflammatory screening, so that the inhibitory effects against NO and PGE₂ production were not caused by non-specific cytotoxicity. Compounds 1h and 2f were the most active PGE₂ inhibitors with IC₅₀ values of 2.94 μM and 4.21 μM, respectively. Western blotting and cell-free COX-2 screening revealed that their effects were due to inhibition of COX-2 protein expression. Moreover, compound 1h exerted strong inhibitory effect on the expression of COX-2 mRNA in LPS-induced murine RAW 264.7 macrophages.