Licochalcone A inhibits the formation and bone resorptive activity of osteoclasts

Licochalcone A on the formation and bone resorptive activity of osteoclasts up to 5 mu M significantly inhibited the receptor activator of nuclear factor kappa B (NF-kappa B) ligand ( RANKL)-induced activity of tartrate-resistant acid phosphatase (TRAP) activity and formation of osteoclasts without any effect on cell viability. Interestingly, licochalcone A was shown to inhibit the RANKL-induced activation of extracellular signal-regulated kinase, translocation of NF-kappa B into nucleus and mRNA expression of Fra-2. Licochalcone A also inhibited the bone resorptive activity of mature osteoclasts and the expression of bone resorption-related genes. Inhibitory effects of licochalcone A on the formation and bone resorptive activity of mouse bone marrow macrophage-derived osteoclasts were also observed. In conclusion, licochalcone A has the potential to inhibit the formation of osteoclasts as well as the bone resorptive activity of mature osteoclasts. (C) 2008 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.