In the current research on Scutellaria baicalensis, a substantial number of flavonoid isomers were identified. Given the limitations of existing analytical methods to accurately identify these isomers, the present study was conducted to determine the flavonoid isomers in Scutellaria baicalensis by combining the mass spectrometry database and stepwise multiple linear regression QSRR model of flavonoids established by the research group in the previous phase. The UHPLC-Q-Exactive Orbitrap-MS technique with isocratic elution injection was employed, and compositional analysis of Scutellaria baicalensis was conducted utilizing the mass spectrometry database to identify two groups of flavonoids and their isomers. The QSRR model was calibrated using standards, and the two groups of flavonoids and their isomers in Scutellaria baicalensis were distinguished and identified utilizing the QSRR model and calibration equation. In this investigation, two groups of flavonoids and their isomers in Scutellaria baicalensis were successfully identified and differentiated. The findings suggest that this QSRR model can be utilized to identify flavonoid isomers, providing a viable method for differentiating isomers of chemical components.
Jun-Yi Zhou,Yan-Qing Chen,Guang Hu,Haiyu Zhao,Jian-Bo Wan
Background N-acylethanolamines (NAEs) are a class of naturally occurring bioactive lipids that play crucial roles in various physiological processes, particularly exhibiting neuroprotective and anti-inflammatory properties. However, the comprehensive profiling of endogenous NAEs in complex biological matrices is challenging due to their low abundance, structural similarity and the limited availability of commercial standards. Here, we propose an integrated strategy for comprehensive profiling of NAEs that combines chemical derivatization and a three-dimensional (3D) prediction model based on quantitative structure-retention time relationship (QSRR) using liquid chromatography coupled with high-resolution tandem mass spectrometry (LC-HRMS). Results After acetyl chloride (ACC) derivatization, the detection sensitivity of NAEs was significantly improved. We developed a QSRR prediction model to construct an in-house database for 141 NAEs, encompassing information on RT, MS 1 ( m/z ), and MS/MS spectra. Propargylamine-labeled fatty acids were synthesized as RT calibrants across various analytical conditions to enhance the robustness of the RT prediction model. NAEs in biological samples were then in-depth profiled using parallel reaction monitoring (PRM) acquisition. This integrated strategy identified and annotated a total of 50 NAEs across serum, hippocampus and cortex tissues from a 5xFAD mouse model of Alzheimer's disease (AD). Notably, the levels of polyunsaturated NAEs, particularly NAE 20:5 and NAE 22:6, were significantly decreased in 5xFAD mice compared to WT mice, as confirmed by accurate quantitation using ACC- d 0 / d 3 derivatization. Significance Our integrated strategy exhibits great potential for the in-depth profiling of NAEs in complex biological samples, facilitating the elucidation of NAE functions in diverse physiological and pathological processes.
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