Protective effects of ugonin K on hydrogen peroxide-induced osteoblast cell damage Yu-Ling Huang a,b , Chia-Hsin Lee c , Jyh-Fei Liao c , Yen-Wenn Liu a , Wen-Fei Chiou a,d, * a National Research Institute of Chinese Medicine, Taipei, Taiwan b Department of Cosmetic Science, Chang Gung University of Science and Technology,Taoyuan,Taiwan c Department of Pharmacology, National Yang-Ming University, Taipei, Taiwan d Department of Biotechnology, Hungkuang University, Taichung, Taiwan ARTICLE INFO Article history: Received 12 January 2015 Received in revised form 24 March 2015 Accepted 30 March 2015 Available online ABSTRACT Oxidative stress is a risk factor in the pathogenesis of osteoporosis.The present results showed that ugonin K, an osteogenic constituent presented in Helminthostachys zeylanica, was more potent than ascorbic acid, α-tocopherol and probucol, in protecting osteoblasts against hy- drogen peroxide (H2O2)-induced oxidative injury in murine osteoblast MC3T3-E1 cells. Ugonin K suppressed H2O2-induced reactive oxygen species (ROS) production and the Annexin V/propidium iodide assay confirmed that decrease in cell viability by H2O2 was due to apop- tosis. Suppression by Ugonin K of H2O2-induced activation of apoptotic signaling was evidenced by a decrease in expressions of cytosolic cytochrome c, active forms of caspase-9, caspase-3 and poly(ADP-ribose)polymerase (PARP).Treatment of cells with caspase inhibitor Ac-DEVD- cho recovered apoptosis and ugonin K decreased H2O2-triggered caspase 3 activity. Ugonin K-induced alleviation of cell viability was concentration-dependently attenuated by the es- trogen receptor (ER) antagonist and the Src inhibitor, suggesting that activation of ER/Src signaling might also participate in the protective mechanisms. Furthermore, post- treatment with ugonin K after H2O2 challenge also rescued H2O2-induced osteoblast cell death. Our results showed that ugonin K protected osteoblasts from oxidative stress through regu- lation of ROS production and suppression of caspase cascade. These results suggest that ugonin K may be an alternative remedy for osteoporosis. © 2015 Elsevier Ltd. All rights reserved. Keywords: Ugonin K Reactive oxygen species (ROS) Osteoblasts Apoptosis Cytochrome c Caspase 1. Introduction Helminthostachys zeylanica (L.) Hook is commonly called “Daodi- Ugon” in Taiwan. It is a pteridophyte that belongs to the genus Helminthostachys and is distributed in Taiwan, India, South China, and the Philippines. H. zeylanica has been used as a traditional medicine for the treatment of bone contusion, fracture, in- flammatory, pyretic, phlogistic syndromes and jaundice (Huang et al., 2010; Huang, Yeh, Shen, & Chen, 2003). Suja, Latha, Pushpangadan, and Rajasekharan (2004) reported that methanolic extract of H. zeylanica has marked hepatoprotective effect against carbon tetrachloride (CCl4)-induced liver damage in Wistar rats. A series of prenylated flavonoids and cyclized geranyl stilbenes were isolated from the rhizomes of H. zeylanica. Furthermore, some of these compounds were found to have * Corresponding author. National Research Institute of Chinese Medicine, No.155-1, Section 2, Li-Nong Street, Beitou, Taipei, Taiwan. Tel.: +886 2 2820 1999 ext. 4481; fax: +886 2 2825 0743. E-mail address: wfchiou@nricm.edu.tw (W.-F. Chiou). http://dx.doi.org/10.1016/j.jff.2015.03.056 1756-4646/© 2015 Elsevier Ltd. All rights reserved. Journal of Functional Foods 15 (2015) 487–496 Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/jff