The structure property and endothelial protective activity of fucoidan from Laminaria japonica

Four antithrombotic fucoidan fractions F1, F2, LF1, and LF2 with different monosaccharide composition, molecular weight, and degree of sulfation and sulfate position were prepared from Laminaria japonica by hot water extraction and radical degradation. Their endothelial protective activity and possible action mechanism were studied using both cell- and rat-based models systematically. By comparison, the low molecular weight (LMW) fucoidan LF1 and LF2 were more potent than the medium molecular weight (MMW) fucoidan F1 and F2 in endothelial protection, down-regulation of von Willebrand Factor, CD31 and CD51 expressing endothelial microparticles in adrenalin-induced arterial endothelial injury rats and human umbilical vein endothelial cell system. However, the highly sulfated fucoidan fractions F2 and LF2 were better at inducing FGFR1c-expressing BaF₃ cell proliferation in the presence of FGF-1, -2, -7, -8, -9 or -10. These results indicated that the chemical property of fucoidan was correlated to its specific biological activity tested. Therefore, defying fucoidan's monosaccharide composition, molecular weight, and degree of sulfation might be important in developing it into a medicine.