Structural characterization and fermentation of a novel Moringa oleifera leaves polysaccharide with hypoglycemic...

Moringa oleifera leaf-derived natural products offer diverse health benefits in metabolic disorders. However, the structural attributes of M. oleifera leaf polysaccharides, their transformations during gastrointestinal digestion, and their influence on gut microbiota and hypoglycemic activity remain insufficiently understood. This study isolated and purified a hypoglycemic polysaccharide (MOP-3) from M. oleifera leaves, primarily composed of arabinose, rhamnose, and galactose, with a molecular weight of 2.019 × 10⁴ Da. Structural analysis identified glycosidic linkages, including →2)-α-L-Fucp-(1→, →2)-α-L-Araf-(1→, →2)-α-L-Rhap-(1→, →3,6)-β-D-Galp-(1→, →6)-β-D-Glcp-(1→, →2)-α-D-Xylp-(1→, →2,4)-β-D-Manp-(1→, →2,3)-α-D-GalpA-6-OMe-(1→, and →4)-β-D-GlcpA-6-OMe-(1→. MOP-3 reshapes gut microbiota by decreasing Firmicutes while increasing Bacteroidetes and Proteobacteria, concurrently stimulating SCFA production, and enhancing GLP-1 secretion in STC-1 cells. The structural characterization and hypoglycemic properties of MOP-3 in this study provide a theoretical basis for further utilization of food polysaccharides.