New cembranoid diterpenes from the Vietnamese soft coral Sarcophyton mililatensis stimulate osteoblastic differentiation in MC3T3-E1 cells.

Chemical investigation of the Vietnamese soft coral Sarcophyton mililatensis resulted in the isolation of four new cembranoid diterpenes, namely (-)-7beta-hydroxy-8alpha-methoxydeepoxysarcophytoxide (1), (+)-7beta,8beta-dihydroxydeepoxysarcophytoxide (2), (-)-17-hydroxysarcophytonin A (3) and sarcophytol V (4), along with two known compounds, (+)-sarcophine (5) and sarcophytoxide (6). The NMR spectral data of the new compounds were completely assigned by using a combination of 2D NMR experiments including (1)H-(1)H COSY, HSQC, HMBC, and ROESY. To investigate the bioactivities of compounds, which act on bone metabolism, we studied the effects of compounds on the function of osteoblastic MC3T3-E1 cells. Compound 1 caused a significant elevation of alkaline phosphatase activity, collagen content, and nodules mineralization compared to those of the control (p<0.05). These results suggest that newly isolated compound 1 has a direct stimulatory effect on bone formation in vitro and may contribute to the prevention for osteoporosis.