Limonium tetragonum Reduces Osteoclast Formation and Resorption through Mitogen-activated Protein Kinase-c-Fos-NFATc1 Signaling Pathways

Osteoporosis is caused by an imbalance of osteoclasts and osteoblasts, and the major treatment technique for treating osteoporosis is to reduce the activity of osteoclastic bone resorption. Limonium tetragonum (LT) is a medicinal plant that contains bioactive molecules with anti-inflammatory and anti-cancer properties. Its effects on osteoclastogenesis, however, remain unclear. Limonium tetragonum extract (LTE) was examined for its inhibitory effect on osteoclastogenesis by TRAP and pit formation assay. As a result, LTE also significantly reduced TRAP formation, the capability to resorb calcium phosphate-coated plates, and F-actin ring formation. LTE reduced RANKL-induced activation of the MAPKs ERK, JNK, and p38 and the production of the transcription factors c-Fos and NFATc1 required for osteoclastogenesis. LTE also reduced the expression of osteoclastogenesis-related genes such as matrix metalloproteinase-9, tartrate-resistant acid phosphatase, and receptor activator of NF-κB. These findings suggest that LTE might be a promising treatment option for bone disorders caused by aberrant osteoclast production and function.