ABSTRACT
Background: Eurycoma longifolia (E. longifolia) has gained remarkable recognition due to its promisingefficacy of stimulating bone formation in androgen-deficient osteoporosis. Numerous in vivo studies haveexplored the effects of E. longifolia on osteoporosis; however, the in vitro cellular mechanism was notdiscovered yet.Objectives: The present study was aimed to investigate the effect of E. longifolia on the proliferation,differentiation and maturation of osteoclasts and the translational mechanism of inhibition of osteoclastogenesis using RAW 264.7 cells as an in vitro osteoclastic model.Materials and methods: Having assessed cytotoxicity, the cell viability, cell proliferation rate and osteoclastic differentiation capacity of E. longifolia was investigated by evaluating the tartrate-resistant acidphosphatase (TRAP) activity in receptor activator of nuclear factor-kB (NF-kB) ligand (RANKL)-inducedosteoclasts. Taken together, the time-mannered expression of osteoclast-related protein biomarkers suchas matrix metallopeptidase-9 (MMP-9), cathepsin-K, TRAP, nuclear factor of activated T-cells cytoplasmic1 (NFATc1), superoxide (free radicals) generation and superoxide dismutase activity were also measuredto comprehend the mechanism of osteoclastogenesis.Results: E. longifolia did not show significant effects on cytotoxicity and cell proliferation of RAW 264.7cells; however, a significant inhibition of cells differentiation and maturation of osteoclasts was observed.Moreover, a significant down-regulation of RANKL-induced TRAP activity and expression of MMP-9,cathepsin-K, TRAP, NFATc1 and generation of superoxide and enhanced superoxide dismutase activitywas observed in E. longifolia treated cell cultures.Conclusion: We anticipated that E. longifolia that enhances bone regeneration on the one hand andsuppresses osteoclast’s maturation on the other hand may have great therapeutic value in treatingosteoporosis and other bone-erosive diseases such as rheumatoid arthritis and metastasis associatedwith bone loss.© 2017 Transdisciplinary University, Bangalore and World Ayurveda Foundation. Publishing Services byElsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).