Novel galectin-8 targeting polysaccharides from Scutellaria baicalensis: Characterization and anti-gastric adenocarcinoma activity.

Currently, galectin-8 has been demonstrated to enhance the proliferation of gastric cancer cells by activating the Ras signaling pathway, indicating its potential as a therapeutic target for gastric cancer. In this study, Scutellaria baicalensis acidic polysaccharide (SBP-A) was prepared and subsequently fractionated into three subfractions (SBP-A-1, SBP-A-2, and SBP-A-3) utilizing ion exchange chromatography. Subsequently, SBP-A-3 was further separated into SBP-A-3-1 and SBP-A-3-2 through the application of gel chromatography. Physicochemical analysis indicated that the compositions of SBP-A subfractions were mainly GalA, Rha, Gal, and Ara, with molecular weights varying from 2.7 kDa to 111.9 kDa. Fluorescence spectroscopy revealed that SBP-A-3-2 was identified as a glycan co-recognized by CRDs located at both termini of galectin-8. Moreover, anti-tumor experiments have demonstrated that SBP-A-3-2 exhibits the most pronounced inhibitory effect on the proliferation and migration of AGS cells, which is attributed to its affinity for galectin-8. The NMR analysis revealed that SBP-A-3-2 is a pectic polysaccharide with an HG domain and a minor proportion of RG-I domain in the main chain, along with trace amounts of trace →3,5)-α-Ara-(1 → and t-β-Gal neutral side chains. These findings provide valuable insights for studies of polysaccharides targeting galectin-8 for tumor treatment.