[Qualitative and quantitative analysis of chemical components of Dracocephalum moldavica based on UPLC-Q-TOF-MS/MS...

Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS/MS) was used to rapidly identify the chemical components in Dracocephalum moldavica, and UPLC was employed to determine the content of its main components. MS analysis was performed using an electrospray ionization(ESI) source and data were collected in the negative ion mode. By comparing the retention time and mass spectra of reference compounds, and using a self-built compound database and the PubChem database, 68 compounds were identified from D. moldavica, including 36 flavonoids, 22 phenylpropanoids, 4 phenols, and 6 other compounds. On this basis, a UPLC quantitative method was established to simultaneously determine 8 main components, i.e., luteolin-7-O-glucuronide, apigenin-7-O-glucuronide, rosmarinic acid, diosmetin-7-O-glucuronide, tilianin, acacetin-7-O-glucuronide, acacetin-7-O-(6″-O-malonyl)-glucoside, and acacetin. A Waters ACQUITY BEH C_(18) column(2.1 mm × 100 mm, 1.7 μm) was used, with acetonitrile and a water solution containing 0.1% formic acid and 0.1% phosphoric acid as the mobile phase for gradient elution. The detection wavelength was set at 330 nm, with a flow rate of 0.4 mL·min~(-1), and the column temperature was maintained at 35 ℃. The 8 components demonstrated good linearity(r≥0.999 9) over a wide mass concentration range(50 or 100 times). The average recovery rate ranged from 97.5% to 105.1%, and the relative standard deviations(RSDs) were 0.90% to 3.4%(n= 6), indicating that the method was simple, accurate, and reliable. In 17 batches of D. moldavica samples, the content of these 8 components ranged from 0.405 to 2.10, 0.063 to 0.342, 0.446 to 2.43, 0.415 to 1.47, 1.57 to 4.34, 0.173 to 0.386, 1.00 to 5.40, and 0.069 to 0.207 mg·g~(-1), respectively. These results indicate significant differences in the internal quality of the samples, highlighting the need for strict quality control to ensure their pharmacodynamic efficacy. This study provides a scientific basis for the rapid discovery of pharmacodynamic substances, comprehensive quality control, and the formulation or revision of quality standards for D. moldavica.