Further data on the structure of brown seaweed fucans: relationships with anticoagulant activity

The composition, molecular weight (MW), anticoagulant activity and nuclear magnetic resonance spectra of various low-molecular-weight fucans (LMWFs) o btained by partial hydrolysis or radical depolymerization of a crude fucoid an extracted from the brown seaweed Ascophyllum nodosum are compared. Fucos e units were found mainly sulfated at O-2, to a lesser extent at O-3, and o nly slightly at O-4, contrary to previously published results for fucoidans from other brown seaweeds, and fucose 2, 3-O-disulfate residues were obser ved for the first time. As the sulfation pattern excluded an alpha-(1 --> 2 )-linked fucose backbone and a high proportion of alpha-(1 --> 4) linkages was found, it would appear that the concept of fucoidan structure needs to be revised. Anticoagulant activity is apparently related not only to MW and sulfation content, as previously determined, but also (and more precisely) to 2-O-sulfation and 2,3-O-disulfation levels. (C) 1999 Elsevier Science L td. All rights reserved.