Precision-characterization and quantitative determination of main compounds in Si-Ni-San with UHPLC-MS/MS based targeted-profiling method.

Mass spectrometry based precision identification of natural products requires the validation of the reference compounds. This study attempted to develop a LC-QTOF MS combined with LC-TQ MS method to precisely characterize the chemicals of Si-Ni-San (SNS), a classic traditional Chinese medicine formula, which is composed of four medicinal plants, and widely used for the treatments of liver disorders. 74 compounds in SNS were provisionally identified by acquiring MS spectra and MS/MS spectra of the possible chemical features, as well as retrieving small-molecule database. By comparing with the accurate MS/MS spectra of reference compounds, 37 compounds in SNS were precisely identified for the first time. In addition, our effort also successfully assigned the origin of each identified compounds against four medicinal plants. Furthermore, we developed a UHPLC-TQ MS based quantitative-profiling method for simultaneous determination of 37 targeted compounds in the different extracts of the raw SNS and commercial lyophilized powders, enabling to facilitate overall quality control of SNS and associated commercial products. Collectively, our finding precisely characterized the main chemicals in SNS, which also provides a new strategy with LC-MS/MS based chemical profiling to precisely identify a diversity of chemicals in Chinese medicinal plants and associated formulae.