cis-Ampelopsin E, a stilbene isolated from the seeds of Paeonia suffruticosa, inhibits lipopolysaccharide-stimulated nitric oxide production in RAW 264.7 macrophages via blockade of nuclear factor-kappa B signaling pathway.

Stilbenes are a class of compounds that has been reported to inhibit a variety of pathological processes during inflammatory reactions. In this study, cis-ampelopsin E, a stilbene isolated from the seeds of Paeonia suffruticosa, was shown to dose-dependently reduce the nitric oxide (NO) production from lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The reduction in the nitric oxide release occurred in parallel with the comparable inhibition of inducible nitric oxide synthase (iNOS) enzyme expression, which was achieved by cis-ampelopsin E's suppressive effect on nuclear factor-kappa B (NF-κB) signaling activation. By inhibiting LPS-induced inhibitor kinase (IKKα/ß) phosphorylation, cis-ampelopsin E significantly decreased LPS-induced IκBα phosphorylation, prevented IκBα degradation, and subsequently reduced the translocating of transcription factor p65 into the nucleus. As a result, the LPS-induced upregulation of NF-κB transcriptional activity was efficiently inhibited. Moreover, it is revealed that cis-ampelopsin E inhibited LPS-induced cyclooxygenase-2 (Cox-2) expression, cPLA2 activation and prostaglandin E2 (PGE2) production. These results, taken together, suggested that cis-ampelopsin E might exert potential anti-inflammatory effects via blockage of the NF-κB signaling pathway.