The polysaccharides from Hemerocallis citrina Baroni alleviate cognitive impairment in high-fat diet/streptozocin-induced type 2 diabetic mice

Diabetes is a global health crisis linked to cognitive decline and metabolic dysfunctions. Plant-derived polysaccharides are important components for biological functions. This study investigates the beneficial effects of individual polysaccharide components and whole polysaccharide complex extracted from dried flowers of Hemerocallis citrina Baroni ( H. citrina ) on type 2 diabetes mellitus (T2DM). Polysaccharides (HCPS-1 and HCPS-2) were isolated from the crude polysaccharides of H. citrina (HCPS), accompanied by a preliminary characterization of the structure. Polysaccharides intervention significantly exerted hypoglycemic effect and alleviated liver damage in high-fat diet (HFD)/streptozotocin-induced T2DM mice. Additionally, polysaccharides intervention significantly increased the number entering correct arm in the Y-maze test, indicating alleviated cognitive impairment. Furthermore, polysaccharides treatment improved peripheral glucose levels, and maintained energy supply to the brain through enhancing brain glucose metabolism and boosting mitochondrial respiratory chain complex activities. These results highlight the potential of H. citrina polysaccharide in managing T2DM and related cognitive impairment. • Polysaccharides from H. citrina improved glucose tolerance and reduced fasting blood glucose in T2DM mice. • Polysaccharides from H. citrina improved lipid metabolism and alleviated liver damage in T2DM mice. • Polysaccharides from H. citrina improved cognitive functions in T2DM mice. • Polysaccharides from H. citrina enhanced glycolysis and TCA cycle in the brain.