Structural characteristics of neutral polysaccharides purified from coix seed and its anti‐insulin resistance effects on HepG2 cells

Abstract Coix seed is recognized as a functional medicinal food due to its valuable biological activities, with polysaccharides being the primary active compounds. In this study, an ultrasonic‐assisted enzymatic extraction technique was employed, and response surface methodology was used to optimize the yield of polysaccharides to 9.55 ± 0.26%. A novel neutral polysaccharide, CSPsN‐1, was purified with a molecular weight of 7.75 kDa. CSPsN‐1 was composed of arabinose, galactose, glucose, xylose, and mannose in molar ratios of 0.48: 7.92: 86.39: 2.42: 2.79. Its backbone composed of →4)‐α‐D‐Glc p ‐(1→ and →3,4)‐α‐D‐Glc p ‐(1→ units, with terminal residues of α‐D‐Glc p . In vitro experiments, CSPsN‐1 enhanced glucose consumption in insulin‐resistant HepG2 cells and upregulated GLUT4 expression by activating the PI3K/AKT signaling pathway. These findings suggest that CSPsN‐1 holds significant promise as a functional ingredient for treating insulin resistance and related metabolic disorders.