Five distinct fucan sulfates from sea cucumber Pattalus mollis: Purification, structural characterization and anticoagulant activities

Fucan sulfates from echinoderm possess characteristic structures and various biological activities. Herein, comprehensive methods including enzymolysis, ion-exchange chromatography and size exclusion chromatography lead to the purification of five fucan sulfates (FSI, FSII, FSIII, FSIV, FSV) from the sea cucumber Pattalus mollis. Chemical composition analysis showed that they were all composed of l-fucose. Their sulfate content was determined by a conductimetric method. The molecular weight (Mw) of FSI, FSII, FSIII, FSIV and FSV were measured as 238.3 kDa, 81.0 kDa, 82.0 kDa, 23.2 kDa and 6.12 kDa, respectively. Detailed NMR spectroscopic analysis revealed that the structural sequence of FSI and FSII was →3)-l-FucS-α(1→, where FucS were Fuc2S4S (10%), Fuc2S (44%), Fuc0S (10%), Fuc4S (36%), that of FSIII was →4)-l-Fuc2S-(α1 → 4)-l-Fuc2S-(α1 → 4)-l-Fuc0S/3S-(α1→, where Fuc0S and Fuc3S were in equal molar, and that FSIV was →4)-l-Fuc2S3S-(α1 → 4)-l-Fuc2S3S-(α1 → 4)-l-Fuc2S-(α1→4)-l-Fuc2S-(α1 → 4)-l-Fuc2S-(α1 → 4)-l-Fuc2S-(α1 → . This is the first report that such a diversity of fucan sulfates were obtained from the same sea cucumber species. Biological activity showed that FSI, FSII, FSIII and FSIV exhibited potent anticoagulant by prolonging the APTT. Among them, FSII, FSIII and FSIV showed the similar potency, while FSI owned the strongest. Structure-activity relationships analysis showed that molecular weight and sulfation degree should be the crucial factors for the activity.