Abstract
Lotus leaf provides unique nutritional properties to the traditional Chinese dish Jiao Hua Ji. However, its functional polysaccharides remain inadequately characterized. This study evaluates the physicochemical properties and hypoglycemic effects of lotus leaf polysaccharides in Jiao Hua Ji. Ultrasonic-assisted enzymatic extraction significantly improved the yield of polysaccharides to 10.35 ± 0.39%. The yield of the polysaccharides as well as uronic acid content demonstrated a strong correlation with the bioactivity. FTIR analysis confirmed the characteristic infrared spectral features associated with glucans. Four polysaccharides were purified and characterized as 719 kDa (Glc/Gal/Ara 98.91:0.44:0.65), 1010 kDa (Glc/Gal/Ara 98.43:1.18:0.39), 447 kDa (Glc/Gal/Ara 97.17:2.02:0.82), and 327 kDa (Glc/Gal/Ara 97.54:2.06:0.4). The purified polysaccharides exhibited enhanced inhibition of α-amylase, positively correlating with molecular weight and glucose content. Molecular docking studies revealed that the polysaccharide successfully occupies the hydrophobic pocket of α-amylase through hydrogen bonds, with a low binding energy of -6.548 kcal/mol. Notably, the purified polysaccharide significantly improved glucose utilization by 157.5% without cytotoxicity. This study may provide a foundational basis for the application of Jiao Hua Ji in hypoglycemic dietary intervention.