title: Importance of sulfate groups for the macrophage-stimulating activities of ascophyllan isolated from the brown alga Ascophyllum nodosum.
abstract: To investigate the role of sulfate groups on the macrophage-stimulating activities of ascophyllan, we prepared desulfated ascophyllan, and its effects on RAW264.7 cells were compared with native ascophyllan. The chemical structural analysis revealed that nearly 21% of sulfate groups of ascophyllan were removed by desulfation reaction, while no significant changes in the molecular mass and monosaccharide composition occurred after desulfation. NO- and cytokine- (TNF-α and G-CSF) inducing activities of the desulfated ascophyllan on RAW264.7 cells were significantly decreased as compared to native ascophyllan. Furthermore, the activity of desulfated ascophyllan to induce reactive oxygen species (ROS) generation from RAW264.7 cells decreased to almost negligible level. Our results suggest that the level of sulfate groups of ascophyllan is an important structural element responsible for the macrophage-stimulating activities. Probably, even the limited removal of sulfate residues sensitive to desulfation reaction may result in significant decrease in the bioactivities of ascophyllan.
authors.affiliation: Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, Nagasaki 852-8521, Japan.
authors.forename: Zedong
authors.initials: Z
authors.lastname: Jiang
authors.forename: Mikinori
authors.initials: M
authors.lastname: Ueno
authors.forename: Tomoki
authors.initials: T
authors.lastname: Nishiguchi
authors.forename: Ryogo
authors.initials: R
authors.lastname: Abu
authors.forename: Shogo
authors.initials: S
authors.lastname: Isaka
authors.forename: Takasi
authors.initials: T
authors.lastname: Okimura
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Oda
mesh_terms: D000818:Animals; D044646:Ascophyllum / Q000737:chemistry*; D002460:Cell Line; D019069:Cell Respiration / Q000187:drug effects; D016207:Cytokines / Q000096:biosynthesis; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008970:Molecular Weight; D009569:Nitric Oxide / Q000096:biosynthesis; D011134:Polysaccharides / Q000737:chemistry* / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013329:Structure-Activity Relationship; D013431:Sulfates / Q000737:chemistry*
chemical_list: D016207:Cytokines; D011134:Polysaccharides; D017382:Reactive Oxygen Species; D013431:Sulfates; C058519:ascophyllin; D009569:Nitric Oxide
keywords: Ascophyllan; Ascophyllum nodosum; DMEM; Desulfated ascophyllan; Dulbecco’s modified Eagle’s minimum essential medium; ELISA; FBS; G-CSF; HBSS; Hanks’ balanced salt solution; LPS; Macrophage-stimulating activity; NBT; NO; ROS; Sulfate groups; TNF-α; enzyme-linked immunosorbent assay; fetal bovine serum; granulocyte colony-stimulating factor; lipopolysaccharide; nitric oxide; nitro blue-tetrazolium; reactive oxygen species; tumor necrosis factor-α