Inhibitory effect of ursane-type triterpenoids from Weigela subsessilis on RANKL-induced osteoclast differentiation

Osteoclasts play an important role in bone metabolism by resorbing the bone matrix. Thus, the compounds inhibiting osteoclasts can treat bone diseases such as osteoporosis. Among the 8 triterpenoids tested, we show that Ilekudinol B isolated from the plant Weigela subsessilis inhibits receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis from bone marrow-derived monocyte/macrophage cells in a dose-dependent manner, whereas it has no significant effect on osteoblast differentiation. Furthermore, Ilekudinol B attenuates the induction of nuclear factor of activated T cells (NFAT) c1 and osteoclast-associated receptor (OSCAR) expression. Our results indicate that Ilekudinol B has the potential to inhibit osteoclast formation by attenuating the signaling cascades associated with RANKL.   Key words: Triterpenoids, osteoclastogenesis, receptor activator of NF-κB ligand (RANKL), inhibitory activity.