Design, Synthesis, and Biological Evaluation of Oligosaccharides Derived from <i>Pleurotus ostreatus</i> Polysaccharide as Potential Neuroprotective Agents

Neurodegeneration has attracted considerable attention due to its extensive damage to the nervous system and broad impact on the population. Studies have shown that fungal polysaccharides, particularly those from mushrooms, have neuroprotective effects. POP-W with this effect was reported by our team. To understand its structure-activity relationship, three oligosaccharides derived from the branched part of POP-W were synthesized and characterized. H₂O₂-induced PC12 cell injury was selected as a model in this study. The biological tests showed that all three synthesized oligosaccharides were nontoxic and exhibited protective effects on H₂O₂-injured PC12 cells. Based on enzymatic activity assays and apoptosis analysis, the oligosaccharide <b>C</b> showed the best therapeutic effect. Further Western blot experiments confirmed that compound <b>C</b> brought neuroprotective effects by regulating Bcl-2/BAX and PI3K/Akt signaling pathways. These results demonstrate that oligosaccharide <b>C</b> possesses strong neuroprotective activity and may serve as a promising lead compound for future neuroprotective agents.