Propyl Gallate Attenuates Methylglyoxal-Induced Alzheimer-like Cognitive Deficits and Neuroinflammation in Mice

Methylglyoxal (MG), a reactive dicarbonyl metabolite associated with diabetes and metabolic disorders, contributes to carbonyl stress, neuroinflammation, and Alzheimer-like neurodegeneration. This study investigated the neuroprotective effects of propyl gallate (PG), a phenolic antioxidant widely used as a food additive, against MG-induced cognitive impairment in mice. Male C57BL/6J mice were exposed to 1% MG in drinking water for eight weeks and orally administered PG (20, 40, or 100 mg/kg/d). Behavioral tests demonstrated that PG significantly improved spatial learning and recognition memory and alleviated anxiety-like behavior induced by MG. Histological and biochemical analyses revealed that PG reduced hippocampal neuronal damage, suppressed tau hyperphosphorylation and amyloid-β (Aβ) accumulation, and attenuated the overexpression of pro-inflammatory cytokines TNF-α and IL-6. Furthermore, PG increased PI3K expression and Akt phosphorylation while reducing activation of GSK-3β, counteracting the MG-induced suppression of this pathway and aligning with reduced tau hyperphosphorylation. These findings indicate that PG protects against MG-related cognitive dysfunction through modulation of neuroinflammatory responses and survival-related signaling pathways, highlighting its potential as a neuroprotective dietary antioxidant for metabolic stress-associated neurodegenerative disorders.