Chemical Characterization of Rheum tanguticum Petiole Juice via Membrane Filtration: A Comparative Analysis Using UPLC–QTOF–MS–MS and Network Pharmacology

Rheum tanguticum​ petiole juice, widely consumed in Tibet as both a vegetable and an herb, exhibits varying chemical compositions depending on the production methods. This study aims to identify the bioactive components in raw juice using ultra-performance liquid chromatography–quadrupole time-of-flight tandem mass spectrometry (UPLC–QTOF–MS–MS) and analyze their antidiabetic properties through network pharmacology. In addition, the effects of the three types of membrane clarification were evaluated. A total of 36 compounds were identified, and a components–targets–pathways–disease network was constructed for diabetes treatment. Among the membranes tested, the 0.2 μm microfiltration membrane exhibited the highest permeate flux and retained significant amounts of total flavonoids, phenolics, and proanthocyanidins, making it the optimal choice for juice clarification. These findings lay the groundwork for the industrial processing and utilization of R. tanguticum petiole juice in China.