Structure characterization and rheological properties of novel polysaccharides extracted from mango seed kernel, and their effects on immunomodulation and human gut microbiota

Mango seed kernel polysaccharides (MSKP) were investigated for their structural characteristics, rheological properties, immunomodulatory effects, and potential benefits for gut health. The molecular weight of extracted MSKP was 4.2 × 10⁴ Da. The primary monosaccharide in MSKP was found to be xylose, which accounted for 25.74 mol% of the total. Fucose, 22.65 mol%, rhamnose, 12.72 mol%, mannose, 11.87 mol%, ribose, 9.21 mol%, glucose, 7.87 mol%, arabinose, 6.11 mol%, and galactose, 3.81 mol%. The proposed structure of MSKP is →4) β -d-Xyl(1 → 4)α-d-Glc(1 → 4) α -d-Gal(1 → 6)β-d-Rib(1 → 3)β-d-Ara(1 → 6)α-d-Glc(1 → 2)β-d-Fuc(1 → 6)α-d-Rha(1→. MSKP solutions exhibited shear-thinning behavior, where viscosity decreased with increasing shear rates. Using an advanced extraction technique, MSKP was shown to enhance immune responses by stimulating nitric oxide production, acid phosphatase activity, and phagocytosis in RAW 264.7 murine cells. Importantly, simulated digestive tests indicated MSKP's resilience, showing no changes in molecular weight, monosaccharide content, or reducing sugar levels, suggesting it could reach the large intestine intact. This resilience promotes the increase of short-chain fatty acids (SCFAs) in the gut, highlighting MSKP's potential as a functional food for supporting gut health and preventing disease.