Abstract
Green-mature soybean (Glycine max) extract (GSE) inhibits the progression of immunoglobulin E-mediated inflammation more than the ordinary yellow-pigmented soybean extract (YSE). The inhibition of nitric oxide (NO) production by GSE in lipopolysaccharide-stimulated RAW264.7 cells has been found to be lower than that by YSE. However, this inhibitory ability became markedly pronounced by visible light irradiation. We investigated the anti-inflammatory effects of GSE and visible light-irradiated GSE (L-GSE) on dextran sodium sulfate (DSS)-induced colitis, immunoglobulin E-independent inflammation, and assessed whether light irradiation affects their anti-inflammatory properties. The severity of DSS-induced colitis was moderated by the ingestion of any of the soybean extracts, and L-GSE was the most effective in moderating the progression in colitis. GSE and L-GSE, except for YSE, inhibited the mRNA expressions of pro-inflammatory cytokines and chemokine in mice colons. All soybean extracts suppressed the mRNA expression of inducible nitric oxide synthase (iNOS), whereas GSE and L-GSE also inhibited the expression of the iNOS protein in the early phase of colitis. These results suggest that GSE is likely to suppress NO production, unlike in vitro results. Unfortunately, a significant difference in the anti-inflammation ability of GSE and L-GSE was not observed in the DSS-induced colitis mice. However, GSE and L-GSE are likely to become new candidate agents for the inhibition of inflammation and excessive NO production.