1′ S-1′-Acetoxychavicol acetate from the rhizomes of Alpinia galanga was known to show potent inhibitory effect on the production of nitric oxide (NO) in lipopolysaccharide-activated mouse peritoneal macrophages. To clarify its mechanism of action, the effects of 1′ S-1′-acetoxychavicol acetate on the expression of interferon-β (IFN-β) mRNA and activation of nuclear factor-κB (NF-κB), both of which participate in the induction of inducible NO synthase, were examined in lipopolysaccharide-activated macrophages. The results were compared with those of two inhibitors of the NF-κB activation, costunolide and caffeic acid phenethyl ester. 1′ S-1′-Acetoxychavicol acetate inhibited IFN-β mRNA expression as well as NF-κB activation, and two related compounds, (±)-1-acetoxy-1-(2-acetoxyphenyl)-2-propene and (±)-1-acetoxy-1-(4-acetoxyphenol)-3-butene, also inhibited IFN-β mRNA expression. In addition, 1′ S-1′-acetoxychavicol acetate inhibited the production of NO stimulated by poly(I:C) via Toll-like receptor 3.
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