Anti-Inflammatory Effects of Catalpalactone Isolated from Catalpa ovata in LPS-Induced RAW264.7 Cells

Catalpa ovata (Bignoniaceae) is widely distributed throughout Korea, China, and Japan. This study investigated the anti-inflammatory effects of catalpalactone isolated from C. ovata in lipopolysaccharide (LPS)-induced RAW264.7 cells. Catalpalactone significantly inhibited nitric oxide (NO) production and inducible NO synthase (iNOS) expression in LPS-induced RAW264.7 cells. The levels of cytokines such as interleukin-6 and tumor necrosis factor-alpha were reduced under catalpalactone exposure in LPS-induced RAW264.7 cells. Additionally, catalpalactone suppressed signal transducer and activator of transcription 1 (STAT-1) protein expression and interferon-beta (IFN-beta) production. Treatment with catalpalactone prevented interferon regulatory factor 3 (IRF3) and nuclear factor-kappa B (NF-kappa B) activation. Taken together, these results suggest that the anti-inflammatory effects of catalpalactone are associated with the suppression of NO production and iNOS expression through the inhibition of IRF3, NF-kappa B, and IFN-beta/STAT-1 activation.