| Consumption of green tea, a rich source of epigallocatechin-3-gallate (EGCG), is associated with increased bone mineral density in humans. The present study demonstrates the effects of EGCG on the formation of mineralized bone nodules by SaOS-2 human osteoblast-like cells. EGCG, at concentrations of 1-5 muM, caused a dose-dependent increase in the number and area of mineralized bone nodules. EGCG also increased alkaline phosphatase (ALP) activity, an early marker of osteoblastic differentiation. This observation was accompanied by an initial increase in cell proliferation followed by a decline in proliferation at the end of the culture period. After 48 hours of treatment, EGCG decreased protein levels of Runx2, a transcription factor that regulates osteoblast maturation by enhancing early-stage differentiation and inhibiting late-stage differentiation. The observed effects of EGCG on bone formation by human osteoblast-like cells suggest that EGCG may have beneficial effects on bone health. |
