According to traditional Chinese medicine, Scutellaria baicalensis Georgi possesses the therapeutic properties of heat-clearing, dampness-drying, diarrhea alleviation, and detoxification, making it a clinically used remedy for respiratory infections. The objective of this study was to investigate the changes in constituent content, pharmacodynamic effects, and material basis of Scutellaria baicalensis Georgi in the plasma of mice infected with respiratory syncytial virus (RSV). The results showed that a sensitive and efficient high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) method was established in this study. Multiple quantitative analyses of Baicalein, Apigenin-7-glucuronide, Baicalin, Oroxylin A 7-O-beta-d-glucuronide, Wogonoside, Norwogonin, Wogonin, Chrysin, and Oroxylin A in mouse plasma revealed a bimodal absorption phenomenon within the time frame of 0.167 h to 6 h post-administration, with the exception of chrysin. Following 6 h of administration, the concentrations of 9 components continued to decrease until they became undetectable. In comparison to the model group, all administered groups exhibited significant reductions in lung index and viral load, with their lung index repair rate and viral suppression rate aligning with the blood concentration-time curve. Finally, through the application of the gray correlation analysis method, we identified Baicalein, Baicalin, Oroxylin A 7-O-beta-d-glucuronide, Wogonoside, Norwogonin, and Wogonin as potential pharmacodynamic material bases of Scutellaria baicalensis Georgi against RSV infection.

Lonicerae japonicae Flos (LJF) possesses a good anti-respiratory syncytial virus (RSV) effect. However, the material basis of LJF in treating RSV is still unclear. In this study, a sensitive and accurate quantitative method based on UHPLC-QQQ MS was established and validated for the simultaneous determination of the 15 ingredients from LJF in RSV-infected mice plasma. Multiple reaction monitoring was performed for quantification of the standards and of the internal standard in plasma. All the calibration curves show good linear regression within the linear range (r² > 0.9918). The method validation results, including specificity, linearity, accuracy, precision, extraction recovery, matrix effect, and stability of 15 ingredients, are all within the current acceptance criteria. This established method was successfully applied to the pharmacokinetic study of 15 compounds from LJF. Furthermore, the repair rate of lung index and the improvement rate of IFN-γ and IL-6 improved after administration of the LJF, indicating that LJF possessed a positive effect on the treatment of RSV infection. Finally, by combining Spearman and Grey relation analysis, isochlorogenic acid B, isochlorogenic acid C, secoxyloganin, chlorogenic acid, and loganic acid are speculated to be the main effective ingredients of LJF in treating RSV. This study lays the foundation for attempts to reveal the mechanisms of the anti-RSV effect of LJF.