Purification, Source Exploration, and Bioactivity Evaluation of Oligosaccharides in Sijunzi Decoction

Sijunzi decoction (SJZD) has been widely used to treat splenic deficiency syndrome. Previous studies confirmed that polysaccharides and non-polysaccharides (NPS) are the main active components of SJZD. This study aimed to investigate the composition and activity of oligosaccharides in NPS. In this study, the oligosaccharide component (named SJZD-OGS), consisting of several different oligosaccharides, was separated and purified from non-polysaccharides of SJZD (SJZD_NPS). Ultra-high-performance liquid chromatography–ion mobility spectrometry–quadrupole time-of-flight mass spectrometry (UHPLC–IMS–QTOF/MS), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) were used to analyze SJZD-OGS. SJZD-OGS, with a molecular weight of 2178 Da, was composed of glucose and fructose, and its chemical composition mainly included fructo-oligosaccharides (FOS) with a degree of polymerization of 3–14 (DP 3–14). The results of oligosaccharide source exploration demonstrated that the chemical composition of SJZD-OGS was different from that of the oligosaccharides of each herb in SJZD. In addition, SJZD-OGS showed good anti-inflammatory activity on macrophage cells and intestinal epithelial cell protective activity. The present work provides experimental evidence for elucidating the pharmaceutical components of SJZD and presents an effective strategy for the research of oligosaccharides in traditional Chinese medicine (TCM).