Metabonomic study on the anti-osteoporosis effect of Rhizoma Drynariae and its action mechanism using ultra-performance liquid chromatography–tandem mass spectrometry

Rhizoma Drynariae (RD) is an effectively traditional Chinese medicine which is usually used in treating osteoporosis, bone fracture, streptomycin ototoxicity and hyperlipemia. Up to now, studies on pharmacological mechanism of RD mostly focus on cell and gene level, little is known about its metabonomics study. The aim of this study is to establish the rats plasma metabonomic profiles of control, model and treatment group, then to investigate the anti-osteoporosis effect of RD and its action mechanism. A total of 21 Wistar rats was divided into three groups: control group, model group and treatment group. The model and treatment rats were injected prednisolone for 12 weeks, at the same time the treatment rats were orally administered RD extract at a therapeutic dose (10 g/kg, expressed as the weight of raw material) once daily throughout the experimental period, control group and model group were orally gavaged approximately volume normal saline solution. After 12 weeks, all plasma samples of three groups were collected and their metabolic profiling changes were analyzed by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS). The resulting dataset was analyzed by principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The identification of all potential biomarkers was performed using reference standard by comparing their mass spectra, MS/MS fragmentation and retention time. Furthermore, clinical biochemistry and biomechanics study were also carried out to ensure the success of the osteoporosis model and to investigate the anti-osteoporosis effect of RD. Obvious separation trend between control and model group was found in PCA score plot, the anti-osteoporosis effect of RD can be indicated in PLS-DA score plot among these three groups. Six potential metabolite biomarkers, Lysophosphatidylcholines (C16:0 LPC, C18:0 LPC, C18:1 LPC and C18:2 LPC), tryptophane and phenylalanine, which were proved to be related with osteoporosis, were identified in the rats plasma. Compared with control group, level of all biomarkers increased significantly in model group, while that was much closer to normal in treatment group. The anti-osteoporosis effect of RD has been reliably confirmed by the metabonomics method. The osteoporosis might be prevented by RD via intervening antioxidant–oxidation balance, tryptophane metabolism and phenylalanine metabolism in vivo in rats.