Biochanin A Stimulates Osteoblastic Differentiation and Inhibits Hydrogen Peroxide-Induced Production of Inflammatory Mediators in MC3T3-E1 Cells

抄録

Phytoestrogens are plant chemicals that are structurally analogous to estrogen and are known to affect estrogenic activity. Biochanin A, a naturally occurring isoflavone, has been identified and detected in various diets and plant species. We examined the effects of biochanin A on the differentiation of osteoblastic MC3T3-E1 cells and the production of local factors in osteoblasts. Biochanin A (1—50 μM) caused a significant elevation of cell growth, alkaline phosphatase (ALP) activity, collagen content, and osteocalcin secretion in osteoblastic MC3T3-E1 cells (p<0.05). The effect of biochanin A (10 μM) in increasing ALP activity and collagen content was completely prevented by the presence of 10⁻⁶ M cycloheximide and 10⁻⁶ M tamoxifen, suggesting that biochanin A's effect results from a newly synthesized protein component and might be partly involved in estrogen action. We then examined the effect of biochanin A on the H₂O₂-induced production of inflammatory mediators in osteoblasts. Biochanin A (1—10 μM) decreased the 0.2 mM H₂O₂-induced production of TNF-α, IL-6 and NO in osteoblasts. These results suggest that biochanin A may be useful as potential phytoestrogens, which play important physiological roles in the prevention of postmenopausal osteoporosis.