The licorice root derived isoflavan glabridin increases the function of osteoblastic MC3T3-E1 cells

Glabridin, an isoflavan purified from licorice root, exhibits diverse biological activities, including estrogen-like activity. To investigate the bioactivities of glabridin, which act on bone metabolism, the effects of glabridin on the function of mouse osteoblastic cell line (MC3T3-E1) and the production of local factors in osteoblasts were studied. Glabridin (1-10 mu M) significantly increased the growth of MC3T3-E1 cells and caused a significant elevation of alkaline phosphatase (ALP) activity, collagen content and osteocalcin secretion in the cells (P < 0.05). The effect of glabridin (10 mu M) 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 glabridin's effect results from a newly synthesized protein component and might be partly involved in estrogen action. Then, the effects of glabridin on the TNF-alpha-induced apoptosis and production of prostaglandin E-2 (PGE(2)) and nitric oxide (NO) in osteoblasts were examined. Treatment with glabridin (1-10 mu M) prevented apoptosis induced by TNF-alpha (10(-10) M) in osteoblastic cells. Moreover, glabridin (50 mu M) decreased the 10(-10) M TNF-alpha-induced production of PGE(2) and NO in osteoblasts. Our data indicate that the enhancement of osteoblast function by glabridin may result in the prevention for osteoporosis and inflammatory bone diseases. (c) 2005 Elsevier Inc. All rights reserved.