Structure characterization of high molecular weight soluble dietary fiber from mushroom Lentinula edodes (Berk.) Pegler and its interaction mechanism with pancreatic lipase and bile salts.

Aimed to evaluate the hypolipidemic effects of high molecular weight soluble dietary fiber extracted from L. edodes (LEHSDF), this study investigated the structure and interaction mechanism of LEHSDF with pancreatic lipase (PL) and bile salts (BS) that were involved in lipid digestion. 1D/2D NMR spectra indicated that the main chain of LEHSDF consisted of (1 → 2,4)-linked β-D-arabinopyranosyl, (1 → 3)-linked α-L-rhamnopyranosyl, (1 → 4)-linked β-D-xylopyranosyl, (1 → 6)-linked and (1 → 4)-linked β-D-glucopyranosyl, with β-D-galactopyranosyl and α-D-mannopyranosyl as terminal unit. Oil red O staining results suggested that LEHSDF had an effective inhibitory effect on lipid accumulation in HepG2 cells. Isothermal titration calorimetry, fluorescence and circular dichroism spectra showed that BS did not specifically bind to LEHSDF, and the strong inhibitory effect of LEHSDF on lipase was dominated by hydrophobic forces, electrostatic forces, encapsulation and adsorption interactions. The results will be helpful for the design of food containing LEHSDF as a functional additive to control lipid digestion.