Preparation, isolation, structural characterization, and cardiomyocyte protection of nine oligosaccharides hydrolyzed from red ginseng polysaccharides

Red ginseng (RG) is widely consumed owing to its tonifying properties. A series of oligosaccharides (F2–F10) with diverse degrees of polymerization were isolated from RG. The extraction yield of crude RG polysaccharide (RGP) reached 13.32%. The isolation procedure entailed partial acid hydrolysis of the total polysaccharides, followed by dialysis and preparative hydrophilic interaction chromatography (HILIC). The structural characteristics of these oligosaccharides were systematically investigated using a suite of analytical techniques, encompassing high-performance liquid chromatography equipped with evaporative light scattering detector (HPLC-ELSD), HILIC/ion mobility-quadrupole time-of-flight mass spectrometry (HILIC/IM-QTOF-MS), and nuclear magnetic resonance spectroscopy (NMR). Comprehensive analysis revealed that the predominant structural motif comprised α -(1→4)-linked glucosyl residues. Each isolated oligosaccharide product manifested as a mixture containing both the α - and β -anomers, a consequence of mutarotation. The purity of all nine oligosaccharides (F2–F10) exceeded 92%, with most fractions achieving purities above 98% as determined by HPLC-ELSD. Additionally, the cardioprotective potential of these oligosaccharides was assessed utilizing an in vitro model of oxygen–glucose deprivation and reperfusion in H9c2 cardiomyocytes. The findings indicated that the oligosaccharides exerted a substantial protective effect on cardiomyocytes. This study reports the isolation and structural characterization of RG-derived malto-oligosaccharide homologs and highlights their cardioprotective potential.