Green tea catechin enhances osteogenesis in a bone marrow mesenchymal stem cell line

Abstract

Green tea has been reported to possess antioxidant, antitumorigenic, and antibacterial qualities that regulate the endocrine system. Previous epidemiological studies found that the bone mineral density (BMD) of postmenopausal women with a habit of tea drinking was higher than that of women without habitual tea consumption. However, the effects of green tea catechins on osteogenic function have rarely been investigated. In this study, we tested (-)-epigallocatechin-3-gallate (EGCG), one of the green tea catechins, on cell proliferation, the mRNA expressions of relevant osteogenic markers, alkaline phosphatase (ALP) activity and mineralization. In a murine bone marrow mesenchymal stem cell line, D1, the mRNA expressions of core binding factors a1 (Cbfa1/Runx2), osterix, osteocalcin, ALP increased after 48 h of EGCG treatment. ALP activity was also significantly augmented upon EGCG treatment for 4 days, 7 days and 14 days. Furthermore, mineralizations assayed by Alizarin Red S and von Kossa stain were enhanced after EGCG treatment for 2-4 weeks in D1 cell cultures. However, a 24-h treatment of EGCG inhibited thymidine incorporation of D1 cells. These results demonstrated that long-term treatment of EGCG increases the expressions of osteogenic genes, elevates ALP activity and eventually stimulates mineralization, in spite of its inhibitory effect on proliferation. This finding suggests that the stimulatory effects of EGCG on osteogenesis of mesenchymal stem cells may be one of the mechanisms that allow tea drinkers to possess higher BMD.

Inulin-type fructans trigger changes in iron concentration and activity of bone metabolism biomarkers in blood plasma of growing pigs

“…The dose-depend relation between dietary ITF and bone mineralization was confirmed (Scholz-Ahrens et al, 2002). It was also demonstrated that polyphenols that are present in the chicory root have the ability to enhance osteogenesis (Chen et al, 2005). Most likely the observed increase in ALP activity in animals fed dried chicory root results from escalated bone mineralization process as an effect of wide spectrum of short-and long-chain ITF and polyphenolic compounds present in dried chicory root.…”

Effects of Vitamin E on the Osteoblast Differentiation

“…It was unclear whether the effects of and -tocopherol on differentiation of osteoblasts are caused by their antioxidant property or non-antioxidant functions in this study. Many reports demonstrated that several antioxidants increased ALP activity in cultured osteoblasts [10,11,12,21,22], indicating that the decrease of ALP activity induced by  and -tocopherol in cultured osteoblasts is not caused by their antioxidant effects. Tocopherol shows several functions at cellular level independent of its antioxidant properties.…”

Effects of silk fibroin hydrolysate on bone metabolism in ovariectomized rats

“…A recent study showed that flavonoid compounds in green tea improve bone density by increasing the activity of osteoblast cells. However, research concerning the tea's composition and the optimal amount of consumption for achieving the bone-related health benefits is lacking (Chen et al, 2005). Additionally, a number of studies have shown that isoflavones, one of the phytoestrogens found in soybeans and soybean products, improve bone health by maintaining bone density and inhibiting bone resorption (Washbum et al, 1999;Song et al, 1999;Arjmandi et al, 1996;Lee et al, 2002;Cassidy 1999).…”