Fructus Benincasae Recens extract prevents cytokine-induced nitric oxide formation and cytotoxicity of RINm5F cells

Abstract

Cytokines produced by immune cells infiltrating pancreatic islets are important mediators of beta-cell destruction in insulin-dependent diabetes mellitus. In this study, the effects of Fructus Benincasae Recens (FBR) extract on cytokine-induced beta-cell dysfunction were examined. Fructus Benineasae Recens extract completely protected interleukin-1beta (IL-1beta) and interferon-gamma (IFN-gamma)-mediated cytotoxicity in rat insulinoma cell line (RINm5F). Incubation with FBR extract resulted in a significant reduction of IL-1beta and IFN-gamma-induced nitric oxide (NO) production, a finding that correlated well with reduced levels of the inducible form of NO synthase (iNOS) mRNA and protein. The molecular mechanism by which FBR extract inhibited iNOS gene expression appeared to involve the inhibition of NF-kappaB activation. Our results revealed the possible therapeutic value of FBR extract for the prevention of diabetes mellitus progression.