Modulation of cytokine gene expression by curcumin

Curcumin, a phytochemical with antioxidant and anti-inflammatory properties, is valued as a cancer chemopreventive agent. Previously, we have shown that curcumin reduces the gene expression of inducible nitric oxide synthase (iNOS) in murine macrophages, in vitro, and in the liver, in vivo. Here, we continued to examine its effect on iNOS expression in other organs. Curcumin inhibited lipopolysaccharide (LPS)-induced iNOS gene expression in the spleen, mesenteric lymph nodes, small intestine and colon. Furthermore, it inhibited gene expression of three cytokines that enhance iNOS production. In vitro, curcumin reduced the gene expression of tumor necrosis factor a (TNFalpha) and interleukin-1beta (IL-1beta) by LPS-stimulated peritoneal cells. In vivo, it reduced the gene expression of TNFa and IL-1beta in the liver and spleen, and reduced the gene expression of interferon gamma (IFNgamma) in the spleen and lymph nodes. Nitric oxide (NO) enhances the activity of cyclooxygenase-2 (COX-2); we found that curcumin also reduced COX-2 gene expression in RAW 264.7 macrophages.