Combined treatment with Dendrobium candidum and black tea extract promotes osteoprotective activity in ovariectomized estrogen deficient rats and osteoclast formation

Aims: Dendrobium candidum (DC) and black tea, are traditional chinese drinks, which contain multiple active ingredients. However, whether or not the combination of these two ingredients can improve osteoporosis remains unknown. This study therefore aimed to examine the effects of the combination of DC and black tea extract (BTE) on osteoporosis. Main methods: Ovariectomy (OVX)-induced osteoporosis in vivo as well as receptor activator of NF-kappa B ligand (RANKL)-induced osteoclastogenesis in vitro was selected. Key findings: Results showed that OVX rats that were treated orally with a DC and BTE combination for 12 weeks maintained their calcium (Ca) and phosphorus (P) homeostasis and exhibited significantly enhanced estradiol (E-2) and OPG levels. This combination treatment also simultaneously reduced levels of interleukin (IL)-1 beta, IL-6 and improved the organ coefficients of the uterus and femur as well as BMD and BMC in OVX rats. In addition, this DC and BTE combination suppressed osteoclast differentiation in the RANKL-stimulated osteoclastogenesis of RAW 264.7 cells and effectively inhibited the expression of osteoclast-associated genes and proteins. The results of this study further highlight the fact that a combination of DC and BTE improved ovariectomy-induced osteoporosis in rats and suppressed RANKL-stimulated osteoclastogenesis in RAW 264.7 cells.