Cyclooxygenase inhibition with curcumin in Helicobacter pylori infection

Helicobacter pylori (H. pylori) infection increases the expression of cyclooxygenase-2 (COX-2) on the host’s gastric mucosa. The inhibition of COX-2 activity with natural products would be a major advantage. This study aims to clarify the possible effect of curcumin on COX-2 inhibition in gastric mucosa of H. pylori infected mice. We inoculated 30 pathogen-free male C57BL/6 mice with H. pylori (SS1 Sidney strain) that were randomly divided in two different groups: infected group (IG) treated with phosphate-buffered saline (PBS) (n = 15) and infected group treated with curcumin 500 mg/kg (IG + C) (n = 15). A group of 15 non-infected mice were used as control (CG). Two weeks post-infection, both IG and CG groups received 0.5 ml of PBS, while the IG + C group received curcumin for 6, 18, and 27 weeks. The analysis by immunohistochemistry and by PCR array at 6, 18, and 27 weeks post-infection showed a significant increase on COX-2 expression on the IG mice compared to the CG mice. The group treated with curcumin (IG + C) showed a significant downregulation of COX-2 at all points of the experiment, when compared to the IG + C mice. Chronic H. pylori infection induces a significant increase in COX-2 expression. Treatment with curcumin significantly decreases the COX-2 expression, and the addition of curcumin to the diet may be an interesting approach for areas of high H. pylori prevalence.