Notoginsenoside R1 significantly promotes in vitro osteoblastogenesis

Notoginsenoside R1 (NGR1), one of the main effective components of Panax notoginseng, appears to be effective in promoting osteogenesis and treating osteoporosis. However, hitherto, whether NGR1 can directly promote osteoblastogenesis remains to be elucidated. In the present study, we hereby examined the effects of NGR1 on the osteoblastogenesis of a pre-osteoblast cell line (MC3T3-E1) in in vitro time-course and dose-dependent experiments. Its efficacy was evaluated by assessing cell viability (indicator of proliferation), alkaline phosphatase (ALP) activity (a marker of early osteoblastic differentiation), levels of osteocalcin (OCN; a marker of late osteoblastic differentiation), calcium deposition (a marker of final mineralization) and the expression of a series of osteoblastogenic marker genes (such as collagen Iα, Runx2, ALP and OCN) at different time points. When examining the proliferation of and ALP activity in the pre-osteoblasts, a bell-shaped dose-response pattern was observed when the cells were treated with various concentrations of NGR1, with a peak being observed at the concentration of 50 µg/ml. NGR1 markedly increased the expression of OCN at the concentration of 1,000 µg/ml in a dose‑dependent manner. Furthermore, treatment with 1,000 µg/ml NGR1 resulted in the highest mineralization by 4.3- and 5.9-fold on the 21st and 28th day, respectively compared with the control group (no treatment). On the whole, our findings indicate that NGR1 significantly promotes the osteoblastogenesis of pre-osteoblasts, which suggests that NGR1 has potential for use as a bone regeneration agent.