A Neutral Polysaccharide from Ginseng Berry Mitigates D-Galactose-Induced Oxidative Stress and Cognitive Deficits...

Oxidative stress contributes to brain aging processes and is implicated in related functional decline. Developing strategies to mitigate oxidative stress is therefore of significant interest. In this study, a neutral polysaccharide (GBPN) was isolated from ginseng berry. Structural analysis revealed that GBPN (molecular weight 1.52 × 10⁴ Da) is primarily composed of glucose (53.18%), arabinose (24.3%), and galactose (16.75%). Glucose exists in the forms of →4)-Glcp-(1→ (32.95%), →6)-Glcp-(1→ (13.81%), and →4,6)-Glcp-(1→ (3.70%), while arabinose exists as →1)-Araf (9.73%), →1)-Arap (5.82%), →2)-Arap-(1→ (0.66%), →5)-Araf-(1→ (7.62%), and →3,5)-Araf-(1→ (1.69%) forms, while galactose exists in the forms of →1)-Galp (3.58%), →3)-Galp-(1→ (1.59%), and →3,6)-Galp-(1→ (12.67%). GBPN adopts a triple-helix conformation and exhibits a curled lamellar appearance. Functionally, GBPN exhibited strong 2,2-diphenyl-1-picrylhydrazyl radical, hydroxyl radical scavenging activity, and iron ion chelation capacity. It can activate the antioxidant system in D-galactose-induced aging-like mice, and simultaneously enhance their learning and memory abilities. Mechanistic analysis revealed that these effects are associated with the kelch-like ECH-associated protein 1/nuclear factor erythroid 2-related factor 2 pathway. These findings suggest that ginseng berry polysaccharides like GBPN hold promise as potential agents for alleviating oxidative stress and cognitive deficits in aging-related contexts.