Study On Mechanism Of Anti-osteoporosis Polygonum Multiforum,Rhizoma Diynariae And Epimedium

Obiective:To investigate the anti-osteoporotic mechanism of Traditional Chinse Medicine, we examined the phytoestrogenic activities of extracts and main components of three anti-osteoporosis Chinese medicine-Polygonum multiforum, Rhizoma drynariae and Epimedium and studied the effects of icarrin from epmedium on estrogen biosynthesis through aromatase.Methods:In this study, HeLa cells were transiently transfected with estrogen receptor (ERα or ERβ)expression vector respectively together with Estrogen Responsive element (ERE)luciferase reporter plasmid and the effects of the three plant extracts and their main components on luciferase reporter activation were examined. The magnetic particle-based17β-estradiol ELISA was used to measure the effects of icariin on estrogen biosynthesis in human granulosa-like KGN cells and rat osteoblast-like UMR-106cell. The quantitative real time RT-PCR (qRT-PCR) was used to study the mRNA expression of aromatase. Western blotting was used to study the protein expression of aromatase. The alkaline phosphatase (ALP) activity was measured to study the differentiation capacity in UMR-106cells.Results:Our results showed that the three plant extracts and their main components could activate ERE reporter though ERa or ERβ in different level. Emodin (10μM) from Polygonum multiforum, naringin(50μM) from Diynaria and icariin (50μM) from Epimedium significantly activated ERE reporter. Icariin significantly promoted17(3-estradiol biosynthesis in KGN cells and UMR-106cells. Icariin increased the mRNA and protein expression of aromatase in KGN cells. Icariin promoted both estrogen biosynthesis and ALP activity in UMR-106cells.Conclusion:Three plant extracts and their main components have phytoestrogenic activity and they can activate ERβ more selectively than ERa. Icariin promotes estrogen biosynthesis in KGN cells by increasing mRNA and protein expression of aromatase. Icariin have antiosteoporotic effect possibly through promoting estrogen biosynthesis in osteoblasts.