Amomum xanthoides extract prevents cytokine-induced cell death of RINm5F cells through the inhibition of nitric oxide formation

We previously showed that Amomum xanthoides extract prevented alloxan-induced diabetes through the suppression of NF-κB activation. In this study, the preventive effects of A. xanthoides extract on cytokine-induced β-cell destruction were examined. Cytokines produced by immune cells infiltrating pancreatic islets are important mediators of β-cell destruction in insulin-dependent diabetes mellitus. A. xanthoides extract completely protected interleukin-1β (IL-1β) and interferon-γ (IFN-γ)-mediated cytotoxicity in rat insulinoma cell line (RINm5F). Incubation with A. xanthoides extract resulted in a significant reduction in IL-1β and IFN-γ-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 A. xanthoides extract inhibited iNOS gene expression appeared to involve the inhibition of NF-κB activation. Our results revealed the possible therapeutic value of A. xanthoides extract for the prevention of diabetes mellitus progression.