Tatarinan O, a lignin-like compound from the roots of Acorus tatarinowii Schott inhibits osteoclast differentiation through suppressing the expression of c-Fos and NFATc1.

Osteoclasts (OC) are large multinucleated cells derived from monocyte/macrophage precursors. Suppressing osteoclastogenesis is considered as an effective therapeutic approach to erosive bone disease. The root of Acorus tatarinowii Schott, a well-known traditional Chinese medicine was used to treat rheumatosis and other inflammatory disease. However, the effects of tatarinan O (TO), one of the lignin-like compounds isolated from the roots of Acorus tatarinowii Schott during bone development are still unclear. In the present study, we explored the effect of TO on RANKL-induced osteoclastogenesis in vitro. TO was found to suppress osteoclast differentiation from RANKL-stimulated mouse bone marrow macrophages (BMMs) without significant cytotoxicity. TO also dose-dependently suppressed bone resorption activity of mature osteoclasts. Additionally, TO apparently inhibited the expression of osteoclastic marker genes, such as MMP-9, Cts K and TRAP. Furthermore, our results showed that TO decreased RANKL-induced expression of c-Fos and NFATc1 without influencing NF-κB activation and MAPK phosphorylation. Hence, for the first time we revealed that TO dose-dependently inhibited osteoclastogenesis from RANKL-stimulated mouse BMMs via decreasing the expression of NFATc1 and c-Fos.

HJB-1, a 17-hydroxy-jolkinolide B derivative, inhibits LPS-induced inflammation in mouse peritoneal macrophages.

Jolkinolide B (JB) and 17-hydroxy-JB (HJB) are diterpenoids from plants and it has been reported that the presence of a C-17 hydroxy group in JB significantly enhances the anti-inflammatory potency of JB. In this study, two HJB derivatives HJB-1 and HJB-2 were generated by the chemical modification of a 17-hydroxy group of HJB. HJB-1 more effectively inhibited TNF-α, IL-1ß and IL-6 release in LPS-stimulated mouse peritoneal macrophages. In addition, HJB-1 reduced LPS-induced mRNA expression of TNF-α, IL-1ß, IL-6, COX-2 and iNOS in a concentration-dependent manner, but did not alter IL-10 mRNA expression. LPS-induced NF-κB activation and MAPK phosphorylation were also effectively inhibited by HJB-1. These results demonstrate that HJB-1 exerts anti-inflammatory effects on LPS-activated mouse peritoneal macrophages by inhibiting NF-κB activation and MAPK phosphorylation and modification of a 17-hydroxy group of HJB may enhance the anti-inflammatory potency of HJB derivatives.