Isolation and purification of an anticoagulant from fermented red seaweed Lomentaria catenata

We attempted to isolate an anticoagulant polysaccharide from marine algae by fermentation of freeze-dried seaweed with nonselective microorganisms present in the seaweed itself. An anticoagulant compound was purified from red algae Lomentaria catenata and the molecular mass of the purified polysaccharide ranged from 100 to 500 kDa. The purified anticoagulant polysaccharide was mainly composed of galactose with small amounts of glucose and it is highly sulfated (21.76% as SO42−). In addition, 9.42% of protein content proved the compound to be a proteoglycan. The anticoagulant activity of the purified compound was assayed by the activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) assays and compared with the classical anticoagulant heparin. It demonstrated >1000 s of APTT activity at 40 μg/mL and the activity is greater than heparin (183 IU/mg, >1000 s of APTT activity at 62.5 μg/mL). The anticoagulant compound showed prolonged activity towards APTT and TT assays but low or no activity for PT. Therefore, the isolated compound may act on the intrinsic and/or common pathways of the blood coagulation system.