Structure and immunostimulating activity of polysaccharides derived from the roots and leaves of dandelion

Two polysaccharides were obtained from dandelion roots (DPR) and dandelion leaves (DPL) via water extraction and ethanol precipitation. Both DPR and DPL were an acid heteropolysaccharide, with a molecular weight of 5.89 × 104 and 28.2 × 104 Da, respectively. Monosaccharide composition results showed that both DPR and DPL contained Man, Glc, Rha, GalA, Glc, Gal, and Ara with a molar ratios of 2.98:1.00:3.67:6.41:2.98:16.70:2.48 and 1.23:1.00:1.06:5.74:2.88:8.59:1.84, respectively. Methylation and NMR analysis showed DPR and DPL, with triple-helix conformations, were mainly composed of 4-ɑ-Galp and 4-ɑ-GalAp, terminated with t-ɑ-Araf, t-ɑ-Rhap, t-ɑ-Glcp and t-ɑ-Manp. DPL showed an immunoprotective effect in cyclophosphamide (Cy)-induced black-bone silky chickens by improving chicken growth performance, increasing the spleen, thymus, and bursa of Fabricius indices, and promoting blood lymphocyte proliferation, the secretion of cytokines (IL-2, IL-6, and INF-γ) and serum immunoglobulin (IgA, IgG, and IgM) levels in a dose-dependent manner. Moreover, the oxidative stress damage in immunosuppressed chickens was significantly reformed after DPL treatment. These findings provide useful information on the potential for application of dandelion polysaccharides as natural nutrients to enhance chicken immune and antioxidant functions.