α-Mangostin inhibits LPS-induced bone resorption by restricting osteoclastogenesis via NF-κB and MAPK signaling.

Background: Excessive osteoclast activation is an important cause of imbalanced bone remodeling that leads to pathological bone destruction. This is a clear feature of many osteolytic diseases such as rheumatoid arthritis, osteoporosis, and osteolysis around prostheses. Because many natural compounds have therapeutic potential for treating these diseases by suppressing osteoclast formation and function, we hypothesized that α-mangostin, a natural compound isolated from mangosteen, might be a promising treatment as it exhibits anti-inflammatory, anticancer, and cardioprotective effects.

Methods: We evaluated the therapeutic effect of α-mangostin on the processes of osteoclast formation and bone resorption. The receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL) induces osteoclast formation in vitro, and potential pathways of α-mangostin to inhibit osteoclast differentiation and function were explored. A mouse model of lipopolysaccharide-induced calvarial osteolysis was established. Subsequently, micro-computed tomography and histological assays were used to evaluate the effect of α-mangostin in preventing inflammatory osteolysis.

Results: We found that α-mangostin could inhibit RANKL-induced osteoclastogenesis and reduced osteoclast-related gene expression in vitro. F-actin ring immunofluorescence and resorption pit assays indicated that α-mangostin also inhibited osteoclast functions. It achieved these effects by disrupting the activation of NF-κB/mitogen-activated protein kinase signaling pathways. Our in vivo data revealed that α-mangostin could protect mouse calvarial bone from osteolysis.

Conclusions: Our findings demonstrate that α-mangostin can inhibit osteoclastogenesis both in vitro and in vivo and may be a potential option for treating osteoclast-related diseases.