%0 Journal Article
%T Kaempferol as a flavonoid induces osteoblastic differentiation via estrogen receptor signaling
%A Ava Guo
%A Roy Choi
%A Ken Zheng
%A Vicky Chen
%A Tina Dong
%A Zheng-Tao Wang
%A G¨¹nter Vollmer
%A David Lau
%A Karl Tsim
%J Chinese Medicine
%D 2012
%I BioMed Central
%R 10.1186/1749-8546-7-10
%X The herb K. galanga is a popular traditional aromatic medicinal plant that is widely used as food spice and in medicinal industries. In the present study, both the estrogenic and osteogenic properties of kaempferol are evaluated.Kaempferol was first evaluated for its estrogenic properties, including its effects on estrogen receptors. The osteogenic properties of kaempferol were further determined its induction effects on specific osteogenic enzymes and genes as well as the mineralization process in cultured rat osteoblasts.Kaempferol activated the transcriptional activity of pERE-Luc (3.98 ¡À 0.31 folds at 50 ¦ÌM) and induced estrogen receptor ¦Á (ER¦Á) phosphorylation in cultured rat osteoblasts, and this ER activation was correlated with induction and associated with osteoblast differentiation biomarkers, including alkaline phosphatase activity and transcription of osteoblastic genes, e.g., type I collagen, osteonectin, osteocalcin, Runx2 and osterix. Kaempferol also promoted the mineralization process of osteoblasts (4.02 ¡À 0.41 folds at 50 ¦ÌM). ER mediation of the kaempferol-induced effects was confirmed by pretreatment of the osteoblasts with an ER antagonist, ICI 182,780, which fully blocked the induction effect.Our results showed that kaempferol stimulates osteogenic differentiation of cultured osteoblasts by acting through the estrogen receptor signaling.Estrogen is known to play a significant role in bone metabolism in addition to its central roe in the reproductive system [1]. The osteoprotective effects of estrogen have been attributed mainly to its inhibitory action resorption of bone and stimulation of bone formation [2,3]. The drastic decrease in estrogen that accompanies menopause with the elevation of bone resoption caused by a rise in osteoclastogenesis is the most common cause of osteoporosis in women [4]. Clinically, estrogen replacement therapy has long been considered as the first-line therapy for preventing and treating osteoporosis in post-menopau
%U http://www.cmjournal.org/content/7/1/10