海带低分子量岩藻聚糖硫酸酯的制备和抗血小板聚集活性研究

目的：研究低分子量海带岩藻聚糖硫酸酯的制备和纯化技术，筛选抗血小板聚集活性的低分子量海带岩藻聚糖硫酸酯。方法：以海带硫酸多糖为原料，采用自由基降解和强阴离子交换色谱技术，制备纯化出高硫酸根和高岩藻糖的低分子量岩藻聚糖硫酸酯；采用体外凝血酶诱导血小板聚集模型，筛选出抗血小板聚集活性的低分子量岩藻聚糖硫酸酯。结果：强阴离子交换色谱能够有效地将复杂的低分子量海带岩藻聚糖硫酸酯分离纯化，得到4个纯度较高的高硫酸根、高岩藻糖的低分子量多糖，其岩藻糖含量超过85% ~ 95%，硫酸根含量35%以上，分子量在20 ku ~ 30 ku。体外抗血小板聚集试验结果证明，这4个高硫酸根高岩藻糖组分的抗血小板聚集活性最高，而低硫酸根组分含有较高的半乳糖、甘露糖和糖醛酸，其抗血小板活性非常低。结论：采用自由基氧化降解和强阴离子交换色谱法，可获得抗血小板活性高的高硫酸根高岩藻糖的低分子量岩藻聚糖硫酸酯。

Preparation and Purification of Low Molecular Weight Fucoidan from Laminaria japonica with Antiplatelet Activity

Objective: Seperation and purification of low molecular weight fucoidan, with antiplatelet aggregation activity. Methods: By radical degradation and strong anion exchange chromatography, low molecular weight fucoidan from Laminaria japonica was prepared and purified. The antiplatelet activity was assessed by thrombin-induced platelet aggregation model in vitro. Results: Seven low molecular weight fucoidan fractions with different sulfate contents, fucose contents and molecular weight were separated from fucoidan from Laminaria japonica by radical degradation and strong anion exchange chromatography. Four fucoidan fractions had good purity with high sulfate and fucose content at 35% and 85%-95%, and molecular weights of 20-30 ku. By comparison, the high sulfated fucoidan with molecular weight of 20-30 ku exhibited higher inhibitory activity on the thrombin-induced platelet aggregation than low sulfate fraction with high content of galactose, mannose and glucuronic acid. Conclusion: Radical degradation and strong anion exchange chromatography was an effective method to obtain highly sulfated low molecular weight fucoidan with high fucose content from fucoidan from Laminaria japonica, with high antiplatelet activity.