Abstract
Glyceollins, which are derived from daidzein in soybean in response to various stimuli or stresses, have been reported to activate antioxidant/detoxifying enzymes in a nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-dependent manner, in addition to exerting anti-inflammatory effects in murine macrophages. As the Nrf2 signaling pathway is known to antagonize nuclear factor (NF)-κB signaling, glyceollins likely have the potential to prevent or treat inflammatory bowel disease. Thus, this study was conducted to examine whether glyceollins could inhibit dextran sulfate sodium (DSS)-induced colitis in a mouse model. Ulcerative colitis (UC) was induced in male BALB/c mice by administering drinking water with 4% DSS for 5 days. Glyceollins (4 or 10 mg/kg of body weight) were orally administered 48 h before and after DSS treatment. We found that glyceollins alleviated histological colon damage and inflammation induced by DSS treatment. More specifically, glyceollins reduced plasma levels of inflammatory cytokines, such as tumor necrosis factor-α and interleukin-6, which were otherwise markedly increased by DSS treatment. Markers of tissue damage, including malondialdehyde and 8-hydroxy-2-guanosine, were significantly increased by DSS treatment; however, this effect was mitigated through concomitant treatment with glyceollins. Furthermore, nuclear accumulation of NF-κB p65 and the expression of inducible nitric oxide synthase were upregulated by glyceollins, consistent with the observed modulation of inflammatory markers. In conclusion, glyceollins have therapeutic potential for UC and merit further clinical study.