Inhibitory effect of caffeic acid phenethyl ester (CAPE) on LPS-induced inflammation of human middle ear epithelial cells

Conclusions. The results suggest that the anti-inflammatory effect of caffeic acid phenethyl ester (CAPE) is due to its inhibition of tumor necrosis factor (TNF)-α expression and interleukin (IL)-8 production. The anti-inflammatory effect of CAPE is possibly through the inhibition of nuclear factor (NF)-κB via the suppression of inhibitor-κB-α (IκB-α) degradation. Objectives. CAPE is a biologically active component of propolis, a resinous material obtained from bee hives, which originates from conifer bark. The effect of CAPE on lipopolysaccharide (LPS)-induced inflammatory reactions is not known. The aim of this study was to evaluate the anti-inflammatory effect of CAPE on cultured human middle ear epithelial cells (HMEECs). Materials and methods. The effect of CAPE on LPS-induced TNF-α expression was evaluated in HMEECs by real-time reverse transcription polymerase chain reaction (RT-PCR). LPS-induced IL-8 production was determined by enzyme-linked immunosorbent assay (ELISA), and LPS-induced IκB-α degradation was followed by Western blot analysis. Results. CAPE significantly inhibited LPS-induced up-regulation of TNF-α in a dose-dependent manner. IL-8 production by LPS was significantly suppressed by the CAPE pretreatment. Furthermore, LPS-induced IκB-α degradation was suppressed by the CAPE pretreatment.