A heteropolysaccharide purified from leaves of Ilex latifolia displaying immunomodulatory activity in vitro and in vivo

A novel polysaccharide (ILP50-2) was extracted, isolated and purified from the leaves of Ilex latifolia Thunb. Its structure was characterized as a repeating unit consisting of alpha-L-Araf-(1 ->,-> 3)-alpha-L-Araf-(1 ->,-> 5)-alpha-L-Araf-(1 ->,-> 3,5)-alpha-L-Araf-(1 ->,-> 2)-alpha-L-Rhap-(1 ->,-> 2,4)-alpha-L-Rhap-(1 ->, beta-D-Galp-(1 ->,-> 4)-beta-D-Galp-(1 ->,-> 4)-beta-D-Glcp-(1 ->,-> 6)-alpha-D-Manp-(1 ->, and -> 3,6)-alpha-D-Galp-(1 ->. The absolute molecular weight of ILP50-2 was 1.49 x 10(5) g/mol, which adapted a compact coil conformation in 0.1 M NaCl solution with R-z of 25.4 nm. Furthermore, ILP50-2 exhibited immunoregulatory activity, mainly through enhancing the phagocytosis ability of macrophages and prompting the release of nitric oxide (NO) and cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-1 beta (IL-1 beta). Simultaneously, ILP50-2 was found to significantly increase the release of ROS and NO in zebrafish embryos, showing immunoregulatory effects in vivo.