To prevent bone loss that occurs with increasing age, certain nutritional and pharmacological factors are needed. In the present study, the ethanol extract from the fruit of Rubus coreanus Miq. (RCE) was investigated for its effect on the function of osteoblastic MC3T3-E1 cells. RCE (10approximately50 microg/ml) caused a significant elevation in cell viability, alkaline phosphatase (ALP) activity, collagen content, and osteocalcin secretion in the cells. The effect of RCE (50 microg/ml) in increasing cell viability, ALP activity, and collagen content was prevented by the presence of 10(-6) M cycloheximide and 10(-6) M tamoxifen, suggesting that RCE's effect results from a newly synthesized protein component and might be partly involved in estrogen action. We then examined the effect of RCE on the H(2)O(2)-induced apoptosis and production of local factors in osteoblasts. Treatment with RCE (10approximately50 microg/ml) decreased the 0.2 mM H(2)O(2)-induced apoptosis and production of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6 and nitric oxide (NO) in osteoblasts. Our data indicate that the enhancement of osteoblast function by Rubus coreanus Miq. may result in the prevention of osteoporosis and inflammatory bone diseases.