Structural characterization, antiproliferative and immunoregulatory activities of a polysaccharide from Boletus Leccinum rugosiceps

A homogeneous water-soluble flaky polysaccharide named LRP-1 (18.82 kDa) was extracted and purified from the rare edible and medicinal fungi Leccinum rugosiceps. The structure characterization of LRP-1 was analyzed by GPC, GC, GC-MS, FT-IR, SEM, 1D/2D NMR, and its antitumor and immunoregulatory activities were determined. The results show that LRP-1 is a new polysaccharide with a backbone which is mainly composed of -> 1-alpha-D-Fucp-3 ->, -> 1-alpha-D-Rhap-3 ->, -> 1-beta-D-Glcp-6 ->, -> 1-beta-D-Glcp-3 -> ,-> 1-alpha-D-Glcp-4 ->,-> 1-beta-D-Galp-6 -> and -> 1-alpha-D-Manp-6 ->. Results of MTT assay show that LRP-1 inhibit the growth of human hepatoma cells HepG-2 and human breast carcinoma MCF-7 cells in vitro. LRP-1 could also induce the secretion of NO and immune factors (IL-6 and TNF-alpha) of RAW264.7. This study suggests that LRP-1 has potential to be used as nu traceutical food with antitumor and immunoregulatory activities. (C) 2020 Elsevier B.V. All rights reserved.