Effects of soybean ethanol extract on the cell survival and oxidative stress in osteoblastic cells

Recent evidence suggests that high concentrations of tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) are thought to increase the apoptosis in osteoblasts and bone resorption and may have important roles in the regulation of osteoblast and osteoclast metabolism, especially in rheumatoid arthritis. The present study was performed to investigate the effect of soybean ethanol extract on the scavenging properties using DPPH and the TNF-alpha and NO production of osteoblastic MC3T3-E1 cells. The soy extract and its fractions according to polarity displayed a strong free radical scavenger activity at 0.01 approximately 0.1g/L, except for aquous fraction which had no significant effect on the function of MC3T3-E1 cells (p < 0.05). TNF-alpha secretion by MC3T3-E1 cells was reduced significantly when stimulated with soy extract (0.05 g/L). Nitrite accumulation in culture medium and apoptosis of MC3T3-E1 cells were induced by the addition of 10(-10) M TNF-alpha, and inhibited by the simultaneous addition of soy extract (0.05g/L).