Comprehensive metabolic profiles of Achyranthes bidentate in rat serum via ultra-high performance liquid chromatography time-of-flight mass spectrometry and their correlation with osteoinductive activity

The osteoinductive effect of crude and salt-processed Achyranthes bidentata is associated with the serum metabolites. Grey relationship analysis between the serum metabolites and osteoinductive effect will help to clarify the bioactive serum metabolites. First, an ultra-high performance liquid chromatography time-of-flight mass spectrometry method was used to develop serum metabolic fingerprint of rats after oral administration of crude and salt-processed Achyranthes bidentata. The MS1 and MS2 data of serum metabolites were scanned in the range of m/z 100–1500 and 50–1200, respectively. The chemical structures of the metabolites were thoroughly elucidated. Two prototypes and twelve metabolites have been identified. Second, osteoblasts were cultured with the drug-containing serum at different time points. The osteoinductive effect of crude and salt-processed Achyranthes bidentata was evaluated by detecting the proliferation rate and alkaline phosphatase activity of osteoblasts. Third, grey correlation analysis was utilized to elucidate the spectral-effect relationship between serum metabolic fingerprints and osteoinductive effect. Finally, the correlation coefficients of ten metabolites, i.e., oleanolic acid, poststerone-M1, chikusetsusaponin V-M1, oleanolic acid-M2, oleanolic acid-M4, spinacoside D-M1, chikusetsusaponin I-M1, betavulgaroside IV-M2, chikusetsusaponin IVa and achyranthoside IV-M1 were above 0.7. Collectively, our work will provide helpful knowledge for the future research on Achyranthes bidentata.