The rapid screening of bioactive constituents within traditional Chinese medicine (TCM) presents a significant challenge to researchers. Prevailing strategies for the screening of active components in TCM often overlook trace components owing to their concealment by more abundant constituents. To address this limitation, a fishing strategy based on offline two-dimensional liquid chromatography (2D-LC) combined with surface plasmon resonance (SPR) was utilized to screen bioactive trace components targeting peroxiredoxin 3 (PRDX3), using Uncaria alkaloids (UAs) as a case study. Initially, an orthogonal preparative offline 2D-LC system combining a positively charged C₁₈ column and a conventional C₁₈ column under disparate mobile phase conditions was constructed. To fully reveal the trace alkaloids, 13 2D fractions of UAs were prepared, and their components were characterized using mass spectrometry (MS). Subsequently, employing PRDX3 as the targeting protein, a SPR-based screening approach was established and rigorously validated with geissoschizine methyl ether (GSM) serving as a positive control for binding. Employing this refined strategy, 29 candidate binding alkaloids were fished from the 13 2D fractions. Notably, combining offline 2D-LC with SPR increased the yield of candidate binding components from 10 to 29 when compared to SPR-based screening alone. Subsequent binding affinity assays confirmed that PRDX3 was a direct binding target for the 12 fished alkaloids, with isovallesiachotamine (IV), corynoxeine N-oxide (CO-N), and cadambine (CAD) demonstrating the highest affinity for PRDX3. Their interactions were further validated through molecular docking analysis. Subsequent intracellular H₂O₂ measurement assays and transfection experiments confirmed that these three trace alkaloids enhanced PRDX3-mediated H₂O₂ clearance. In conclusion, this study introduced an innovative strategy for the identification of active trace components in TCM. This approach holds promise for accelerating research on medicinal components within this field.

Evaluating the consistency of herb injectable formulations could improve their product quality and clinical safety, particularly concerning the composition and content levels of trace ingredients. Panax notoginseng Saponins Injection (PNSI), widely used in China for treating acute cardiovascular diseases, contains low-abundance (10%-25%) and trace saponins in addition to its five main constituents (notoginsenoside R₁, ginsenoside Rg₁, ginsenoside Re, ginsenoside Rb₁, and ginsenoside Rd). This study aimed to establish a robust analytical method and assess the variability in trace saponin levels within PNSI from different vendors and formulation types. To achieve this, a liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) method employing multiple ions monitoring (MIM) was developed. A "post-column valve switching" strategy was implemented to eliminate highly abundant peaks (NR₁, Rg₁, and Re) at 26 min. A total of 51 saponins in PNSI were quantified or relatively quantified using 18 saponin standards, with digoxin as the internal standard. This study evaluated 119 batches of PNSI from seven vendors, revealing significant variability in trace saponin levels among different vendors and formulation types. These findings highlight the importance of consistent content in low-abundance and trace saponins to ensure product control and clinical safety. Standardization of these ingredients is crucial for maintaining the quality and effectiveness of PNSI in treating acute cardiovascular diseases.
Ginsenosides ; Saponins ; Chemometrics ; Panax notoginseng ; Cardiovascular Diseases ; Chromatography, Liquid ; Tandem Mass Spectrometry