标题：Styraxoside A Isolated from the Stem Bark of Styrax japonica Inhibits Lipopolysaccharide-Induced Expression of Inducible Nitric Oxide Synthase and Cyclooxygenase-2 in RAW 264.7 Cells by Suppressing Nuclear Factor-kappa B Activation
摘要：In the present study, the effects of terpenes (styraxosides A and B) and lignans (egonol, masutakeside I, and styraxlignolide A) isolated from the stem bark of Styrax japonica S IEB . et Z UCC . (styracaceae) were evaluated on lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production by the RAW 264.7 macrophage cell line. Of the tested compounds, styraxoside A was found to most potently inhibit the productions of NO and PGE2, and also significantly reduced the release of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). Consistent with these observations, the protein expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and the mRNA expression levels of iNOS, COX-2, TNF-α and IL-1β were found to be inhibited by styraxoside A in a concentration-dependent manner. Furthermore, styraxoside A inhibited the LPS-induced DNA binding activity of nuclear factor-κB (NF-κB). Taken together, our data indicate that styraxoside A inhibits LPS-induced iNOS, COX-2, TNF-α, and IL-1β expressions through the down-regulation of NF-κB-DNA binding activity.
