Composition and cytotoxicity of a novel polysaccharide from brown alga (Laminaria japonica)

A novel polysaccharide WPS-2-1, with an average molecular weight of 80 kDa, was purified from aqueous extracts of Laminaria japonica. Monosaccharides analysis revealed that WPS-2-1 was composed of mannose, rhamnose and fucose with a molar ratio of 1.0:2.3:1.2. Analysis by periodate oxidation-Smith degradation indicated that WPS-2-1 had a backbone of array by (1 → 4)-glycosidic linkages. Cytotoxicity assay showed that WPS-2-1 presented significantly higher antitumor activities against A375 and BGC823 cells with a dose-dependent manner, and exhibited lower cytotoxicity to vascular smooth muscle cells. The results suggested that WPS-2-1 should be explored as a potential antitumor agent with low toxicity.