Modulatory effects of luteolin on osteoblastic function and inflammatory mediators in osteoblastic MC3T3-E1 cells

The effects of luteolin on the function of osteoblastic MC3T3-E1 cells and the production of local factors in osteoblasts were investigated. Luteolin (1 μM) caused a significant elevation of collagen content, alkaline phosphatase (ALP) activity, and osteocalcin secretion in the cells (P < 0.05). The effect of luteolin in increasing collagen content and ALP activity was completely prevented by the presence of 10−6 M cycloheximide and 10−6 M tamoxifen, suggesting that luteolin's effect results from a newly synthesized protein component and might be partly involved in estrogen action. We then examined the effect of luteolin on the 3-morpholinosydnonimine (SIN-1)-induced production of oxidative stress markers [nitric oxide (NO) and prostaglan E2 (PGE2)] and cytokines [tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6)] in osteoblasts. Luteolin (1 and 10 μM) decreased the SIN-1-induced production of NO, PGE2, TNF-α, and IL-6 in osteoblasts. These results suggest that inflammatory mediators can be regulated by luteolin stimulating osteoblastic function.