Structural Characterization and Molecular Docking Studies of Fresh Coconut Meat Polysaccharides

Abstract

Fresh coconut meat polysaccharides (FCMPs) are high-value natural active polysaccharides with both medicinal and edible uses, but their structural characteristics and potential biological activities have not been well studied. In this work, FFCMP was separated and purified by sequential application of water extraction and alcohol precipitation methods, the Sevag method, DEAE-52 cellulose column chromatography, and Sephadex G-100 gel column chromatography, yielding four components (FCMP 1-FCMP 4). High-performance liquid chromatography (HPLC) was used to determine their molecular weights as 343,016.9, 2279.4, 1363.2, and 2228.9 Da, respectively. Structural characterization and monosaccharide analysis revealed that the FCMP series primarily consists of mannose, glucose, galactose, arabinose, and rhamnose. Methylation experiments and nuclear magnetic resonance (NMR) indicated that FCMP 1 exhibits a complex topological structure with a β-1→4 main chain, β-1→6 branches, and an α-L-rhamnose terminal; FCMP 2 is a heteropolysaccharide with a β-(1→3)-mannan main chain containing β-(1→6)-galactose branches; the main chain of FCMP 3 consists of β-D-mannose and β-D -galactose, with side chains containing α-L-rhamnose and terminal α-L-arabinose and β-D-mannose; and FCMP 4 has a main chain primarily composed of glucose and mannose linked via 1→4 bonds, with some C6 positions exhibiting 1→6 branch structures. Molecular docking predictions suggest that the FCMP series of polysaccharides possess immunomodulatory, anti-inflammatory, and edema-treating properties, providing a theoretical basis for their application in pharmacology and food science research.