Analysis of Herbal Constituents and In Vivo Pharmacokinetics of <i>Gegen–Huangqi</i> Decoction in Rat Plasma Using HPLC‐Q‐TOF‐MS/MS and HPLC‐QQQ‐MS/MS

The traditional Chinese medicine (TCM) formula, gegen-huangqi (GH) decoction, has been employed for over 200 years, notably for its therapeutic effects in treating conditions such as atherosclerosis and diabetes mellitus. Despite its long-standing use, comprehensive studies on the chemical constituents of GH and their in vivo pharmacokinetics (PK) remain limited. This study aimed to profile the bioactive compounds present in GH decoction and to explore their PK characteristics using HPLC-Q-TOF-MS/MS. Furthermore, a robust and validated analytical method was developed and applied to assess the PK of 11 plasma compounds using HPLC-QQQ-MS/MS. In total, 79 components were identified within the GH decoction. Pharmacokinetic analysis revealed distinct absorption and elimination profiles for compounds such as puerarin, daidzin, genistin, calycosin-7-O-β-D-glucoside, and ononin, which exhibited profiles of quick absorption and excretion. Conversely, compounds such as daidzein, formononetin, genistein, astragaloside II, astragaloside IV, and calycosin showed more complex in vivo metabolic patterns, leading to multipeak concentration-time curves. All compounds, except astragalosides II and IV, were found to undergo significant hepatic clearance. These findings provide valuable insights into the pharmacokinetic behavior of GH decoction, which lays the foundation for further quality control, pharmacological exploration, and potential clinical application of this traditional remedy.