Osteogenic effects of Phlomis umbrosa via up-regulation of Runx2 in osteoporosis

Phlomis umbrosa Turcz (labiatae) has been suggested to promote bone growth. However, the anti-osteoporotic effects of P. umbrosa have not yet been elucidated. In the present study, the osteogenic effects of P. umbrosa were investigated in an osteoporosis model. ICR female mice were ovariectomized (OVX) to induce osteoporosis for 7 weeks. Treatment with 1, 10 and 100 mg/kg P. umbrosa was administrated orally to the OVX mice for 6 weeks. At the end of experiment, the microstructure of the capital femoral epiphysis was investigated. The levels of bone mineral density (BMD), bone mineral content (BMC) and serum osteocalcin concentration were evaluated. In addition, mineralized Saos-2 osteoblast cells were treated with 0.01, 0.1 and 1 µg/ml P. umbrosa to analyze the expression of osteoblast differentiation-associated factors. Hyperplasia of the growth plate in the femur was recovered by P. umbrosa treatment. BMD and BMC were significantly increased in P. umbrosa-treated femurs. Serum calcium concentration was increased following P. umbrosa treatment. In addition, the ratio of mineralization was markedly increased in P. umbrosa-treated differentiated osteoblasts along with increases in Runx2 levels. P. umbrosa conferred its osteogenic effects by upregulating Runx2 in osteoporosis. P. umbrosa may be a potential therapeutic material for the treatment of osteoporosis.