Objective:To further investigate the in vitro effects of an osteoprotective herbal formula “ELP”(Herba Epimedii,Fructus Ligustri Lucidi and Fructus Psoraleae) using seropharmacological approach.Methods:Rats were fed with ELP or its individual component herbs for 2 days.The serum containing the post-absorbed ingredients of the herbal items were collected for cell culture using UMR106 cell,RAW264.7cell and mesenchymal stem cell(MSC) isolated from the bone marrow of the rats.The effects of the herbal-containing serum on cell toxicity were detected by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay;bromodeoxyuridine assay was conducted to measure the cell proliferation of UMR106 cell and MSC;cell activity was measured using colorimetric method,and mRNA expression of runt-related transcription factor 2(Runx2),alkaline phosphatase(ALP) and osteopontin(OPN) of UMR106 and MSC as well as matrix metalloproteinase 9(MMP-9),tartrate-resistant acid phosphatase(TRAP) and cathepsin K of RAW264.7 were analyzed using real-time reverse-transcription polymerase chain reaction.Results:ELP and its component serum exhibited no cytotoxic effects on the cells.The ELP-containing serum increased the proliferation of UMR106 cell and MSC by 25.7%and 14.4%,respectively and the alkaline phosphatase activity of MSC was increased by 42.6%.On the contrary,it inhibited the RAW264.7 cell differentiation by 29.2%.ELP serum upregulated the Runx2 expression of UMR and MSC by 1.18 fold and 1.27 fold,respectively.It also upregulated ALP and OPN expression in MSC by 1.69- and 2.12-fold,respectively.On the other hand,ELP serum down-regulated MMP-9 and cathepsin K expression of RAW264.7 cell by 0.46- and 0.36-fold,respectively.Conclusions:The serum of the animals fed with ELP contains active ingredients which are effective in promoting osteogenesis and inhibiting osteoclastogenesis. Objective: To further investigate the in vitro effects of an osteoprotective herbal formula “ELP” (Herba Epimedii, Fructus Ligustri Lucidi and Fructus Psoraleae) using seropharmacological approach. Methods: Rats were fed with ELP or its individual component herbs for 2 days. The serum containing the post-absorbed ingredients of the herbal items were collected for cell culture using UMR106 cells, RAW 264.7 cell and mesenchymal stem cell (MSC) isolated from the bone marrow of the rats. Effects of the herbal-containing serum on cell toxicity were detected by 3- [4,5-dimethylthiazol-2-yl] -2,5-diphenyltetrazolium bromide assay; bromodeoxyuridine assay was conducted to measure the cell proliferation of UMR106 cell and MSC; cell activity was measured using colorimetric method, and mRNA expression of runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP) and osteopontin (OPN) of UMR106 and MSC as well as matrix metalloproteinase 9 (MMP-9), tartrate-resistant acid phosphatase (TRAP) and catheps in K of RAW264.7 were analyzed using real-time reverse-transcription polymerase chain reaction. Results: ELP and its component serum exhibited no cytotoxic effects on the cells. ELP-containing serum increased the proliferation of UMR106 cell and MSC by 25.7% , and 14.4%, respectively and the alkaline phosphatase activity of MSC was increased by 42.6% .On the contrary, it inhibited the RAW264.7 cell differentiation by 29.2% .ELP serum upregulated the Runx2 expression of UMR and MSC by 1.18 fold and 1.27 fold , respectively.It also upregulated ALP and OPN expression in MSC by 1.69- and 2.12-fold, respectively. On the other hand, ELP serum down-regulated MMP-9 and cathepsin K expression of RAW264.7 cells by 0.46- and 0.36- fold, respectively. Conclusions: The serum of the animals fed with ELP contains active ingredients which are effective in promoting osteogenesis and arrested osteoclastogenesis.