Preparation of relative low molecular mass fucoidan from Laminaria japonica and its effect on the fibrinolytic system

Objective To investigate relationship of the chemical character and fibrinolytic activity of relative low molecular mass fucoidan from Laminaria japonica.Methods Two relative low molecular mass fucoidan fractions were obtained by radical depolymerization and ultrafiltration of a crude fucoidan from Laminaria japonica.The effects of relative low molecular mass fucoidan on the fibrinolytic system in rabbit were evaluated by euglobulin lysis time,plasma clot dissolution time and activities of u-PA,t-PA and PAI-1.Results and Conclusion Two highly sulfated fucoidan from Laminaria japonica with weight-average molecular mass(Mw) 7.68kD and 3.89kD were obtained by hydroxyl radical generated from copper-catalyzed decomposition of H2O2 and step-by-step ultrafiltration.Fucoidan fraction with Mw of 7.68 kD was mainly composed of fucose and galactose,and its sulfate group content was 30.32%,which was lower than that of fraction with molecular mass of 3.89kD(32.4%).The analysis of FT-IR showed that the sulfate group was mainly on the C4.Euglobulin lysis time and plasma clot dissolution time in rabbit blood were effectively shortened by relative low molecular mass fucoidan intravenously.Relative low molecular mass fucoidan could effectively enhance the activity of t-PA and inhibit the activity of PAI-1,but had no influence on u-PA.Fucoidan fraction with Mw of 7.68kD exhibited better effect on euglobulin lysis time and t-PA.The results showed that relative low molecular mass fucoidan from L.japonica had good fibrinolytic activity.