Antioxidative, hypolipidemic, and anti-inflammatory activities of sulfated polysaccharides from Monostroma nitidum

Polysaccharides from seaweed have different biological activities. Two types of sulfated polysaccharides (SPs) were purified from Monostroma nitidum (MF1 and MF2) and investigated for biological activities in vitro. The MF1 and MF2 fractions exhibited strong antioxidant activities assessed using superoxide dismutase (SOD) assays. Stimulation of lipid-loaded hepatocytes by the MF1 and MF2 fractions significantly (p < 0.05) reduced cellular lipid concentrations, compared with controls. Quantitative PCR analysis revealed that reductions in cellular lipid concentrations accompanied reduced expressions of cholesterol synthesis genes, and induced gene expressions for cholesterol degradation, LDL uptake, and peroxisomal beta-oxidation. Gene expressions related to inflammation, including inducible NO synthase (iNOS), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), interleukin-8 (IL-8), and visfatin, were suppressed in lipid-loaded hepatocytes stimulated with MF1 and MF2. SPs from M. nitidum exhibited hypolipidemic and anti-inflammatory activities.