This study investigates the anti-inflammatory effects of a
stilbene compound,
desoxyrhapontigenin, which was isolated from Rheum undulatum. To determine the anti-inflammatory effects of this compound,
lipopolysaccharide (LPS)-induced RAW 264.7 macrophages were treated with different concentrations of six
stilbene derivatives. The results indicated that compared with other
stilbene compounds,
desoxyrhapontigenin (
at 10, 30 and 50μM concentrations) significantly inhibited
nitric oxide (NO) production,
nuclear factor kappa B (NF-κB) activation, the
protein expression of
cyclooxygenase-2 (COX-2) and
inducible nitric oxide synthase (iNOS) expression. Therefore, the anti-inflammatory mechanism of
desoxyrhapontigenin was investigated in detail. The results of this investigation demonstrated that
desoxyrhapontigenin suppressed not only LPS-stimulated pro-inflammatory
cytokine secretions, including the secretions of
tumor necrosis factor alpha (TNF-α) and
interleukin-6 (IL-6), but also
PGE2 release. As assayed by electrophoretic mobility shift assays (EMSAs),
desoxyrhapontigenin also produced the dose-dependent inhibition of the LPS-induced activation of NF-κB and
AP-1. Moreover,
desoxyrhapontigenin inhibited the
protein expression of myeloid differentiation primary response gene 88 (MyD88), IκB
kinase (IKK) phosphorylation and the degradation of IκBα. Activations of p-JNK1 and p-Akt were also significantly inhibited, and phosphorylation of p38 and ERK was down-regulated. A further study revealed that
desoxyrhapontigenin (5 and 25mg/kg, i.p.) reduced paw swelling in
carrageenan-induced acute
inflammation model in vivo. On the whole, these results indicate that
desoxyrhapontigenin showed anti-inflammatory properties by the inhibition of iNOS and COX-2 expression via the down-regulation of the MAPK signaling pathways and the inhibition of NF-κB and Akt activation.