Icaritin ameliorates diabetes-associated cognitive dysfunction by attenuating ferroptosis through PPARα/CPT1A-associated fatty acid oxidative regulation

Ethnopharmacological relevance Diabetes-associated cognitive dysfunction (DACD) is a neurological complication of diabetes characterized by impaired learning and memory. Epimedium is a traditional Chinese medicinal herb used for conditions associated with diabetes and cognitive decline. Icaritin (Y003), a bioactive prenylated flavonoid derived from Epimedium and an active metabolite of flavonoid glycosides such as icariin, has shown glucose-lowering and neuroprotective effects. However, its effects on DACD and underlying mechanisms remain unclear.Aim of the study This study aimed to explore the efficacy and mechanisms of Y003 against DACD in vivo and in vitro.Materials and methods A DACD mouse model was established using HFD/STZ and treated orally with Y003. Cognitive function, metabolic disturbances, tissue pathology, gut microbiota, metabolomics, brain fatty acid profiles, protein expression, and ferroptosis-related indices were evaluated using complementary behavioral, biochemical, histological, multi-omics, and molecular analyses. In parallel, HG/PA-treated HT22 cells were used to evaluate Y003 effects, with ferrostatin-1 (Fer-1), GW6471(GW), and etomoxir (ETO) used for pharmacological validation of ferroptosis and PPARα/CPT1-associated regulation.Results Y003 markedly ameliorated glucose and lipid metabolic disturbances, cognitive deficits, and hippocampal neuronal injury in DACD mice. Multi-omics analyses revealed coordinated alterations in gut microbiota composition, peripheral metabolism, and medium- and long-chain fatty acid profiles in brain tissue, suggesting microbiota-gut-brain axis-associated metabolic remodeling. In brain tissue, Y003 restored PPARα and CPT1A expression and CPT1 activity while reducing lipid peroxidation and iron accumulation and improving antioxidant defense, consistent with attenuation of ferroptosis-related injury. In HG/PA-treated HT22 cells, Y003 improved cell viability and reduced lipid ROS accumulation. Fer-1 produced similar protective effects, whereas GW and ETO partially attenuated Y003-mediated protection. These findings suggest that the protective effects of Y003 are associated with restoration of PPARα/CPT1A-associated fatty acid oxidative capacity and attenuation of ferroptosis-related injury.Conclusion Y003 may ameliorate metabolic disturbances and cognitive dysfunction in DACD through microbiota-gut-brain axis-associated fatty acid metabolic remodeling and restoration of PPARα/CPT1A-associated fatty acid oxidative capacity, providing a scientific basis for further preclinical and clinical investigation.