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

BACKGROUND: Cranberry (Vaccinium 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 IκBα 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 IκBα was determined. The results indicated that cranberry extract and quercetin decreased COX‐2 expression and suppressed degradation of IκBα in unstimulated cells. In PMA‐stimulated cells, cranberry extract was also able to decrease COX‐2 expression and suppress degradation of IκBα. 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. Copyright © 2008 Society of Chemical Industry