Aciculatin inhibit RANKL-induced osteoclastogenesis in RAW 264.7 cells

Chrysopogon aciculatis (Retz.) Trin. (Poaceae) is a perennial herb and widely distributed in lower altitudes in Taiwan. It has been used to treat fever and common cold as a traditional Chinese medicine. In the current study, the whole grass of C. aciculatis was heated under reflux with 95% ethanol, and then partitioned with a sequence of ethyl acetate (EtOAc), n-butanol and water. Aciculatin, 8-(2,6-dideoxy-beta-ribo- hexopyranosyl)-5-hydroxy-2-(4-hydroxyphenyl)-7-methoxy-4 H-1-benzopyran-4-one, was obtained and identified from EtOAc extract. We investigate the effects of aciculatin on osteoclastogenesis. Receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclastogenesis in RAW 264.7 cells was used as a platform for osteoclast assessment. Cell viability was examined using thiazolyl blue tetrazolium bromide (MTT) assay. Tartrate resistant acid phosphatase (TRAP) activity and staining were determined in multinucleated osteoclasts. The protein and mRNA expression was analyzed by Western blotting and real-time PCR. The results showed that aciculatin can inhibit osteoclast differentiation in RANKL-induced RAW 264.7 cells. Aciculatin regulated expression of nuclear factor of activated T cells (NFATc1), which plays an important role in osteoclast differentiation, and nuclear factor kappa B (NFκB) signaling pathway. The present in vitro results suggest that aciculatin may be useful in treating or preventing osteoporosis in vivo.