Studies on the hepatoprotective effect of fucoidans from brown algae Kjellmaniella crassifolia

For illustrating the relation of different structural characteristics correlated with the hepatoprotective effect, studies of fucoidan from algae Kjellmaniella crassifolia, a brown alga distributed in north Japan, were carried out. The fucoidan fractions of K. crassifolia were extracted, separated, and purified using a combinatorial procedure consisting of enzymolysis, ethanol precipitation, DEAE and size-exclusion chromatographies. The fundamental characteristics of the four enriched fucoidan fractions (KF1-KF4), including their sulphate content and monosaccharide composition, were investigated. The fucose was the main composition of monosaccharide for KF1-KF4, that of KF4 was up to 91.4%. The Glu-UA was the special composition of monosaccharide. FTIR and NMR spectroscopy were employed to elucidate the structural features of all fractions which further illustrated that fucose was the main monosaccharide. It was found all the four fractions showed antioxidative activity against hydroxyl radical and had the bioactive effects on CCl4-induced liver injury.