College of Food Science and Engineering, Ocean University of China, No. 5, YuShan Road, Qingdao, Shandong Province 266003, PR China.
College of Food Science and Engineering, Ocean University of China, No. 5, YuShan Road, Qingdao, Shandong Province 266003, PR China.; The Technology Center of Qingdao Customs, No. 70, Qutangxia Road, Qingdao 266001, China.
Int J Biol Macromol. 2019 Jul 1;132:738-747. doi: 10.1016/j.ijbiomac.2019.03.127. Epub 2019 Mar 20.
To minimize undesired pharmacological activities and improve the bioavailability, the fucoidan and fucosylated chondroitin sulfate (FCS) from Holothuria floridana were depolymerized under hydrothermal conditions and the mechanism underlying hydrothermal depolymerization was proposed. Our results demonstrated that fucoidan and FCS from Holothuria floridana were able to be gradually depolymerized without desulfation at 100-121 °C by control of pH at 5-6 to obtain controlled molecular weight. It was the first time to find that pH also plays a key role on the hydrothermal depolymerization of fucoidan and FCS. The monosaccharide composition, FT-IR and NMR analysis showed that the structure of the optimized hydrothermal depolymerized fucoidan and FCS remained almost unchanged. By comparison, FCS was more difficult to be depolymerized than fucoidan under the same hydrothermal condition. The oligosaccharide profile in depolymerized fucoidan and FCS by HILIC-MS analysis further revealed that FCS was depolymerized with preferential cleavage of β-1 → 4 glycosidic linkage and decarboxylation on glucuronic acid during hydrothermal treatment, which was quite different with the random fracture type of fucoidan due to their different structure. These results indicated that hydrothermal depolymerization and action mechanism of fucoidan and FCS from sea cucumber were quite different for their different structure.
为了最小化非预期的药理活性并提高生物利用度，采用水热条件对仿刺参中的岩藻聚糖硫酸酯和硫酸软骨素进行降解，并提出了水热降解的作用机制。结果表明，通过控制 pH 值在 5-6 之间，可以在 100-121℃的温度范围内实现仿刺参岩藻聚糖硫酸酯和硫酸软骨素的逐步降解而不发生脱硫，从而得到可控分子量的产物。这是首次发现 pH 值在岩藻聚糖硫酸酯和硫酸软骨素的水热降解中也起着关键作用。单糖组成、FT-IR 和 NMR 分析表明，优化后的水热降解岩藻聚糖硫酸酯和硫酸软骨素的结构几乎保持不变。相比之下，在相同的水热条件下，硫酸软骨素比岩藻聚糖更难降解。通过 HILIC-MS 分析对降解后的岩藻聚糖硫酸酯和硫酸软骨素的寡糖图谱进一步表明，在水热处理过程中，硫酸软骨素优先通过β-1→4糖苷键断裂和葡萄糖醛酸脱羧进行降解，这与岩藻聚糖的随机断裂类型完全不同，这是由于它们的结构不同所致。这些结果表明，由于结构的不同，海参岩藻聚糖硫酸酯和硫酸软骨素的水热降解和作用机制有很大的不同。
