Extraction, Fractionation, and Chemical Characterisation of Fucoidans from the Brown Seaweed Sargassum pallidum

The fucoidans were obtained by extraction with water and gradient precipitation with different concentrations of ethanol. The main structural characterisations and bioactivities were achieved. Four fractions of water-soluble crude fucoidans with different molecular weights - SPC60, SPC70, SPH60, SPH70 - were extracted from S. pallidum collected from the Yellow Sea, China, using cold water and hot water extraction, and fractional precipitation with gradient concentrations of ethanol. Chemical analysis demonstrated that all of these fucoidan fractions consisted of fucose, rhamnose, xylose, mannose, glucose, and galactose with different monosaccharide mole ratios. Fractions SPC60, SPC70, and SPH70 showed moderate cytotoxic activity against P388 murine leukaemia cells. Fucoidan is a kind of bioactive polysaccharide from the brown algae. This study provides a fast and feasible method to obtain fucoidans from S. pallidum, which can be used as pharmaceutical material and functional food.