Cranberry extract and quercetin modulate the expression of cyclooxygenase-2 (COX-2) and IκBα in human colon cancer cells

BACKGROUND: Cranberry (Voccinium marcocarpon) fruit and quercetin, a major flavonoid found in cranberries, are likely contributors to chemoprevention, and their anti-inflammatory activities may play a potential role in colon cancer prevention. The aim of this study was to examine the effect of cranberry extract and quercetin on basal expression of cyclooxygenase-2 (COX-2) and I kappa B alpha as well as the effect on phorbol 12-myristate 13-acetate (PMA)-induced COX-2 expression in colon cancer cells. RESULTS: HT-29 human colon adenocarcinoma cells were treated with various concentrations of cranberry extract or quercetin and/or PMA, and the protein expression of COX-2 and I kappa B alpha was determined. The results indicated that cranberry extract and quercetin decreased COX-2 expression and suppressed degradation Of I kappa B alpha in unstimulated cells. In PMA-stimulated cells, cranberry extract was also able to decrease COX-2 expression and suppress degradation Of I kappa B alpha. CONCLUSION: The results suggest that a possible mechanism involved in the anti-cancer activity of cranberry and quercetin is partly mediated through its anti-inflammatory action. These findings indicate that cranberry and quercetin may reduce the risk of colon cancer possibly by suppressing inflammatory responses. (C 2008 Society of Chemical Industry