A mixture of Pueraria lobata and Platycodon grandiflorum extracts ameliorates RANKL-induced osteoclast differentiation and ovariectomy-induced bone loss by regulating Src- PI3K-AKT and JNK/p38 signaling pathways.

ABSTRACT

Osteoporosis is caused by increased bone resorption due to the excessive activity of osteoclasts. Pueraria lobata has demonstrated the ability to improve bone density in ovariectomized mice, and Platycodon grandiflorum can suppress osteolysis biomarkers such as collagen content in cartilage and alkaline phosphatase activity. In this study, we examined whether HX112, a mixture of Pueraria lobata and Platycodon grandiflorum extracts, could inhibit the receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-induced osteoclast differentiation to alleviate osteoporosis. To induce the differentiation of osteoclasts, RAW 264.7 cell were cultured with RANKL and HX112. Osteoclasts differentiation was evaluated by TRAP activity and TRAP staining. Bone resorption as osteoclasts major function was assessed by pit formation assay. As a result, HX112 suppressed osteoclast differentiation and bone resorptive function. Additionally, HX112 reduced the expression of osteoclastogenic genes including NFATc1 and c-Fos, and these effects of HX112 were mediated by inhibiting Src-phosphoinositide 3-kinase (PI3K)- Protein kinase B (Akt) and c-Jun N-terminal kinase (JNK)/p38 signaling pathways. Furthermore, ICR mice were ovariectomized to induce osteoporosis and bone mineral density of femur was measured using micro-CT. Consequently, oral administration of HX112 to ovariectomized mice significantly improved bone microstructure and bone mineral density. Collectively, these findings indicate that the mixed extract of Pueraria lobata and Platycodon grandiflorum may be useful as therapeutics for osteoporosis.