Although fluoxetine, a selective serotonin reuptake inhibitor, is known to demonstrate antiinflammatory activity, little information is available on the effect of fluoxetine regarding intestinal inflammation. This study investigates the role of fluoxetine in the attenuation of acute murine colitis by suppression of the NF-B pathway in intestinal epithelial cells (IEC). Fluoxetine significantly inhibited activated NF-B signals and the upregulated expression of interleukin-8 (IL-8) in COLO 205 colon epithelial cells stimulated with tumor necrosis factor-␣ (TNF-␣). Pretreatment with fluoxetine attenuated the increased IB kinase (IKK) and IB␣ phosphorylation induced by TNF-␣. In a murine model, administration of fluoxetine significantly reduced the severity of dextran sulfate sodium (DSS)-induced colitis, as assessed by the disease activity index, colon length, and histology. In addition, the DSS-induced phospho-IKK activation, myeloperoxidase activity, a parameter of neutrophil accumulation, and the secretion of macrophage-inflammatory protein-2, a mouse homolog of IL-8, were significantly decreased in fluoxetine-pretreated mice. Moreover, fluoxetine significantly attenuated the development of colon cancer in mice inoculated with azoxymethane and DSS. These results indicate that fluoxetine inhibits NF-B activation in IEC and that it ameliorates DSS-induced acute murine colitis and colitis-associated tumorigenesis, suggesting that fluoxetine is a potential therapeutic agent for the treatment of inflammatory bowel disease.

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We already showed that the plant sterol guggulsterone has been reported to inhibit nuclear factor-kB (NF-kB) signaling in intestinal epithelial cells (IECs) and to attenuate dextran sulfate sodium (DSS)-induced colitis. This study investigates the anti-inflammatory effects of novel guggulsterone derivatives on IEC and preventive and therapeutic murine models of DSS-induced colitis. Novel guggulsterone derivates with high lipophilicity were designed and four derivates, including GG-46, GG-50B, GG-52, and GG-53, were synthesized. Two guggulsterone derivatives, GG-50B and GG-52, significantly inhibited the activated NF-kB signals and the upregulated expression of interleukin-8 (IL-8) in COLO 205 cells stimulated with tumor necrosis factor-a (TNF-a). Pretreatment with GG-50B and GG-52 attenuated the increased IkB kinase (IKK) and IkBa phsophorylation induced by TNF-a. In preventive and therapeutic models of murine colitis, administration of GG-52 significantly reduced the severity of DSS-induced colitis, as assessed by disease activity index, colon length, and histology. In contrast, GG-50B did not show a significant reduction in the colitis severity. Moreover, the efficacy on attenuating colitis by GG-52 was comparable to that by sulfasalazine or prednisolone. These results indicate that the novel guggulsterone derivative GG-52 blocks NF-kB activation in IEC and ameliorates DSS-induced acute murine colitis, which suggests that GG-52 is a potential therapeutic agent for the treatment of inflammatory bowel diseases.