Structural characterization and neuroprotective effect of coix seed polysaccharides

Coix seed is a medicinal-edible plant rich in bioactive polysaccharides. While coix seed polysaccharide (CSP) exhibits broad pharmacological activities, its neuroprotective potential against neurodegenerative diseases remains underexplored. This study identified CSP as a heteropolysaccharide with two distinct molecular weight peaks (552 Da and 35,011 Da), primarily composed of glucose. It has a triple-helical structure and exhibits strong, dose-dependent antioxidant properties. In vitro antioxidant assays demonstrated strong radical scavenging capacity, with IC 50 values of 2.56 mg/mL for ABTS radical and 2.75 mg/mL for •OH. Crucially, CSP pretreatment significantly protected PC12 cells against H 2 O 2 -induced oxidative damage, evidenced by a 41.56% increase in cell viability at 1.6 mg/mL ( P  < 0.05). Additionally, CSP increased the activity of superoxide dismutase (SOD) and catalase (CAT) in a dose-dependent manner, raised glutathione (GSH) levels, and reduced the release of lactate dehydrogenase (LDH) and the content of malondialdehyde (MDA) in PC12 cells exposed to H 2 O 2 . Moreover, CSP significantly reduced reactive oxygen species (ROS) accumulation and attenuated apoptosis. Taken together, these findings elucidate CSP's neuroprotective mechanism via oxidative stress mitigation, supporting its potential development as a therapeutic agent or functional food component for neurodegenerative disorders.