[Pharmacokinetics of Baihe Dihuang Decoction in normal and depression rats]

A total of 9 constituents(catalpol, rehmannioside A, rehmannioside D, ajugol, aucubin, regaloside A, regaloside B, regaloside C, and regaloside E) from Baihe Dihuang Decoction in the plasma samples of normal and depression rats were simultaneously determined by ultra-performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS). Normal and depression model rats were used to study the pharmacokinetics and elimination patterns of active constituents from Baihe Dihuang Decoction. A depression model was established in rats via the chronic unpredictable mild stress(CUMS) protocol. After gavage with Baihe Dihuang Decoction, blood samples were collected from orbital venous plexus of both normal and model rats at designated time points. Ultra-high performance liquid chromatography-triple quadrupole-mass spectrometry(UHPLC-QqQ-MS) was employed to investigate the pharmacokinetics of 9 major compounds in the multiple reaction monitoring(MRM) mode. Key pharmacokinetic parameters were determined through non-compartmental mode analysis in Phoenix 64. The results revealed significant differences in the pharmacokinetic profiles of the constituents of Baihe Dihuang Decoction between the normal and model groups. Compared with the normal group, the model group exhibited significant increases in the C_(max) values and decreases in T_(max) of catalpol, aucubin, and regaloside A. For regaloside B, regaloside C, and regaloside E, the AUC, MRT, t_(1/2), and T_(max) were higher in the model group than in the normal group. Rehmannioside A and rehmannioside D showed similar trends, with lower C_(max), AUC, t_(1/2), and T_(max) in the model group than in the normal group, and their plasma concentration-time curves shifted from a double-peak profile in the normal group to a single-peak profile in the model group. These marked differences in the pharmacokinetic characteristics of Baihe Dihuang Decoction between normal and model groups indicate that the physiological state can substantially alter the absorption and elimination of the decoction, providing a scientific basis for its administration.