Epigallocatechin-3-gallate Inhibits the Expression of Adhesion Molecules by Blocking Nuclear Factor Kappa B Signaling in Intestinal Epithelial Cells

ABSTRACT

BACKGROUND/AIMS: Epigallocatechin-3-gallate (EGCG) is the main polyphenol in green tea and has anti-inflammatory and anti-oxidative effects. The aim of this study was to determine the impact of EGCG on the expression of adhesion molecules and lipopolysaccharide (LPS)-induced nuclear factor-kappa B (NF-kappaB) signaling in rat intestinal epithelial (RIE) cells. METHODS: The effect of EGCG on LPS-induced NF-kappaB signaling and expression of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 was examined by reverse transcription polymerase chain reaction, western blotting, immunofluorescence and electrophoretic mobility shift assay. RESULTS: LPS-induced expression of ICAM-1 and VCAM-1 mRNA was inhibited by EGCG treatment in RIE cells. LPS-induced inhibitor of kappa B alpha degradation and NF-kappaB nuclear translocation were blocked by EGCG in RIE cells. EGCG blocked LPS-induced NF-kappaB DNA-binding activity in RIE cells. The pharmacological NF-kappaB inhibitor Bay11-7082 suppressed the LPS-induced expression of ICAM-1 and VCAM-1 mRNA in RIE cells. CONCLUSIONS: These results indicate that EGCG inhibits LPS-induced ICAM-1 and VCAM-1 expression by blocking NF-kappaB signaling in intestinal epithelial cells.