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Open Access Highly Accessed Research article

Water extract of Spatholobus suberectus inhibits osteoclast differentiation and bone resorption

Hyunil Ha, Ki-Shuk Shim, Hyosun An, Taesoo Kim* and Jin Yeul Ma*

Author Affiliations

KM-Based Herbal Drug Research Group, Korea Institute of Oriental Medicine, Daejeon, 305-811, Republic of Korea

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BMC Complementary and Alternative Medicine 2013, 13:112  doi:10.1186/1472-6882-13-112

Published: 21 May 2013

Abstract

Background

Osteoclasts are primarily responsible for bone resorption. In many pathological bone diseases including osteoporosis and rheumatoid arthritis, osteoclasts are excessively activated. Thus, controlling of osteoclasts would be an effective therapeutic strategy for the treatment of excessive bone loss. The stem of Spatholobus suberectus has been widely used in traditional medicine to treat blood stasis syndrome and arthritis in Asia. In the present study, we investigated the effects and action mechanism of water extract of the stem of Spatholobus suberectus (WESS) on osteoclast differentiation and function.

Methods

The effect of WESS on osteoclast differentiation was evaluated by counting tartrate resistant acid phosphatase-positive multinucleated cells in bone marrow-derived macrophages system and murine bone marrow cell-osteoblast coculture system. Bone resorption activity of mature osteoclast was examined on a calcium phosphate-coated plate. Actin ring structure of osteoclasts was detected fluorescently by staining for F-actin. Activation of signaling pathways and induction of transcription factors required for osteoclastogenesis were investigated by real-time PCR and Western blotting.

Results

WESS effectively inhibited osteoclast differentiation from its precursors. The inhibitory effect of WESS on osteoclast differentiation was due to the suppression of osteoclastogenic transcription factors, c-Fos and nuclear factor of activated T cells cytoplasmic 1 expression, via preventing receptor activator of nuclear factor-κB ligand-induced early signaling pathways and decreasing c-Fos protein level in osteoclast precursors. Furthermore, WESS suppressed bone resorption activity of osteoclasts by disrupting actin ring structure.

Conclusions

This study demonstrated that WESS inhibits osteoclast differentiation and function. These results suggest that WESS has a potential for treating pathological bone diseases caused by excessive bone resorption.

Keywords:
Osteoporosis; Spatholobus suberectus; RANKL; Osteoclasts; Bone resorption