Structural characterization of polysaccharides from Saposhnikovia divaricata and their antagonistic effects against the immunosuppression by the culture supernatants of melanoma cells on RAW264.7 macrophages.
Two purified native polysaccharides, namely, SDNP-1 and SDNP-2 with apparent molecular weight of 67.9×103 and 5.2×103, separately, were isolated from the water extract of Saposhnikovia divaricata by combined ion-exchange and gel permeation chromatography. The structures of these polysaccharides were characterized by high-performance gel permeation chromatography, chemical derivative analysis, GC-MS, FT-IR spectroscopy, and NMR spectroscopy. Results showed that SDNP-1 and SDNP-2 were composed of arabinose and galactose with molar ratio of approximately 1:1. The polysaccharides were deduced to be AGII-type arabinogalactans with distinct molecular weights and backbone chains. The backbone chain of SDNP-2 mainly consisted of (1→3)-linked and (1→6)-linked Galp residues with an approximate molar ratio of 1:3. Approximately half of the (1→6)-linked Galp residues were substituted at O-3, and small amounts of (1→6)-linked Galp were substituted at O-3 and O-4 by branches that mainly consisted of terminal and (1→5)-linked Araf residues. Bioactivity tests showed that SDNP-2 exhibited significant antagonistic effect against immunosuppression as shown by the cell viability of the culture supernatants of melanoma cells on RAW264.7 macrophages. However, SDNP-1 showed no effect. Thus, molecular weight and backbone chain may be the key factors for the antagonistic effects against immunosuppression.
['Dong|Cai-Xia|CX|', 'Liu|Liu|L|', 'Wang|Chang-Ying|CY|', 'Fu|Zheng|Z|', 'Zhang|Ying|Y|', 'Hou|Xuan|X|', 'Peng|Chao|C|', 'Ran|Rui-Xue|RX|', 'Yao|Zhi|Z|']
D000818:Animals D019661:Apiaceae D007108:Immune Tolerance D008545:Melanoma D051379:Mice D008970:Molecular Weight D011134:Polysaccharides D000067996:RAW 264.7 Cells
Structural characterization Polysaccharide Saposhnikovia divaricata Antagonistic effect Immunosuppression