Structural characterization and protective effects of polysaccharides isolated from M. fruits on HO-induced oxidative damage in RINm5F pancreatic β-cells.

Our previous research demonstrated the hypoglycemic and antioxidant properties of crude polysaccharides from M. (BDP), but the structural characteristics and underlying mechanisms were unclear. In this study, a homogeneous polysaccharide, BDP-I, was isolated and structurally characterized. BDP-I had a molecular weight of 3.947 kDa and consisted of arabinose, galactose, glucose, and galacturonic acid, mainly linked through →6)-β-D-GalAp-(1→ glycosidic bonds.An oxidative stress model was established by treating RIN-m5F pancreatic islet cells with 250 μmol/L HO for 3 hours. BDP-I intervention at concentrations ranging from 0.0625 to 0.5 mg/mL significantly improved cell viability, reduced reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS), and enhanced superoxide dismutase (SOD) and catalase (CAT) activities in a dose-dependent manner.Untargeted metabolomics revealed that BDP-I regulated 46 potential biomarkers, effectively reversing metabolic disturbances caused by oxidative stress. In addition, BDP-I modulated the expression of genes associated with apoptosis and mitochondrial damage, including iNOS and NF-κB.These findings suggest that BDP-I exerts protective effects against oxidative damage in pancreatic islet cells through multiple mechanisms, highlighting its potential as a targeted antioxidant agent for functional food or therapeutic applications.