Abstract：
Marine green algae produce sulfated polysaccharides with diverse structures and a wide range of biological activities. This study aimed to enhance the biotechnological potential of sulfated heterorhamnan (Gb1) from Gayralia brasiliensis by chemically modifying it for improved or new biological functions. Using controlled Smith Degradation (GBS) and O-alkylation with 3-chloropropylamine, we synthesized partially water-soluble amine derivatives. GBS modification increase sulfate groups (29.3 to 37.5 %) and α-l-rhamnose units (69.9 to 81.2 mol%), reducing xylose and glucose, compared to Gb1. The backbone featured predominantly 3- and 2-linked α-l-rhamnosyl and 2,3- linked α-l-rhamnosyl units as branching points. Infrared and NMR analyses confirmed the substitution of hydroxyl groups with aminoalkyl groups. The modified compounds, GBS-AHCs and GBS-AHK, exhibited altered anticoagulant properties. GBS-AHCs showed reduced effectiveness in the APTT assay, while GBS-AHK maintained a similar anticoagulant activity level to Gb1 and GBS. Increased nitrogen content and N-alkylation in GBS-AHCs compared to GBS-AHK may explain their structural differences. The chemical modification proposed did not enhance its anticoagulant activity, possibly due to the introduction of amino groups and a positive charge to the polymer. This characteristic presents new opportunities for investigating the potential of these polysaccharides in various biological applications, such as antimicrobial and antitumoral activities.
摘要：
海洋绿藻产生结构多样、生物活性广泛的硫酸化多糖。这项研究旨在通过对巴西盖拉利亚的硫酸化异鼠南（Gb1）进行化学修饰以改善或新的生物学功能，从而增强其生物技术潜力。使用受控的史密斯降解（GBS）和与3-氯丙胺的O-烷基化，我们合成了部分水溶性胺衍生物。GBS修饰增加硫酸盐基团（29.3至37.5％）和α-L-鼠李糖单位（69.9至81.2mol％），减少木糖和葡萄糖，与GB1相比。主链主要以3-和2-连接的α-L-鼠李糖基和2,3-连接的α-L-鼠李糖基单元为分支点。红外和NMR分析证实羟基被氨基烷基取代。改性化合物，GBS-AHC和GBS-AHK，表现出改变的抗凝血特性。GBS-AHC在APTT分析中显示出降低的有效性，而GBS-AHK维持与Gb1和GBS相似的抗凝活性水平。与GBS-AHK相比，GBS-AHC中氮含量和N-烷基化的增加可能解释了它们的结构差异。提出的化学修饰没有增强其抗凝血活性，可能是由于引入了氨基和聚合物的正电荷。这一特征为研究这些多糖在各种生物应用中的潜力提供了新的机会。如抗菌和抗肿瘤活性。
