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)-alpha expression and interleukin (IL)-8 production. The anti-inflammatory effect of CAPE is possibly through the inhibition of nuclear factor (NF)-kappaB via the suppression of inhibitor-kappaB-alpha (IkappaB-alpha) degradation.

OBJECTIVE

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).

METHODS

The effect of CAPE on LPS-induced TNF-alpha 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 IkappaB-alpha degradation was followed by Western blot analysis.

RESULTS

CAPE significantly inhibited LPS-induced up-regulation of TNF-alpha in a dose-dependent manner. IL-8 production by LPS was significantly suppressed by the CAPE pretreatment. Furthermore, LPS-induced IkappaB-alpha degradation was suppressed by the CAPE pretreatment.