Herbal formulation, Yukmi-jihang-tang-Jahage, regulates bone resorption by inhibition of phosphorylation mediated by tyrosine kinase Src and cyclooxygenase expression

Abstract

Anti-bone resorption properties of the Korean herbal medicine, Yukmi-jihang-tang (YJ), which is comprised of seven herbs such as Rehmannia glutinosa Libosch, Dioscorea japonica THUNB, Cornus officinalis SIEB et. ZUCC, Smilax glabra ROXB, Paeonia suffruticosa ANDR, Alisma platago-aquatica var. orientale SAMUELS and Hominis placenta, were investigated. Cyclooxygenase-2 (COX-2) and tyrosine kinase involve on prostaglandin E2 (PGE2) production in mouse calvarial osteoblasts stimulated by cytokine interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and/or interleukin-6 (IL-6). IL-1β and IL-6 and to a lesser extent TNF-α, enhanced COX-2 mRNA levels in calvarial osteoblasts. TGF-β, YJ (100 μg/ml) and their combinations of YJ + TGF-β reduced the COX-2 mRNA level, PGE2 biosynthesis and bone resorption induced by IL-1β, TNF-α, IL-6 or their combination. Finally, YJ inhibits in vitro and in vivo bone resorption by inhibition of phosphorylation of peptide substrates. The parathyroid hormone-induced bone resorption in mouse fetal long bone cultures was inhibited with an IC 50 of 16 μg/ml. YJ dose-dependently reduced the hypercalcemia induced in mice by IL-1β and partly prevented bone loss and microarchitectural changes in young ovariectomized rats, showing that the protective effect on bone was exerted via the inhibition of bone resorption. These results indicate that the synergy between IL-β, TNF-α, IL-6 on PGE2 production is due to an enhanced gene expression of COX-2 and that tyrosine kinase(s) are involved in the signal transduction of COX-2 in mouse calvarial osteoblasts. Thus, YJ as a possible Src family kinase inhibitor may be useful for the treatment of diseases associated with elevated bone loss. This result also suggested that the YJ extracts is effective for bone resorptive action in bone cells.