Hypoglycemic activity of enzymatically extracted Eucommia ulmoides polysaccharide (EUL-w1) on IR-HepG2 cell via the AMPK/PI3K/Akt signaling pathway

This study devised optimal conditions to extract Eucommia ulmoides leaf (EUL) polysaccharides using a cellulase and pectinase composite enzyme system based on one-way experiments and response surface methodology. Crude EUL polysaccharides (EULPs) were extracted and purified using a DEAE chromatography column. The polysaccharides EUL-w, EUL1, EUL2, and EUL3 were obtained by elution with water, 0.1 mol/L NaCl, 0.2 mol/L NaCl, and 0.3 mol/L NaCl, respectively. The EUL-w fraction had the highest hypoglycemic activity based on its α-amylase and α-glucosidase activities. The preliminary structure of purified EUL-w1 was elucidated. In vitro hypoglycemic activity studies and metabolomics analyses suggested that EUL-w1 modulated glucose metabolism by mediating the AMPK/PI3K/Akt signaling pathway. Our findings provide novel insights and data support for the utilization of EULPs as an emerging food resource in functional foods.