不同生长期养殖萱藻(Scytosiphon lomentarius)中褐藻胶和褐藻糖胶的结构分析

Structures analysis of alginates and fucoidans from cultured Scytosiphon lomentarius in different growing stages

目的提取分离不同生长期养殖萱藻的褐藻胶和褐藻糖胶,分析其结构,明确生长期对褐藻胶与褐藻糖胶产率及结构的影响。方法分别以生长期为45、60和75d大连海域养殖的萱藻为材料,经过80℃2%Na2CO3水溶液提取,稀HCl沉淀获得不同生长期萱藻褐藻胶SL45A、SL60A和SL75A,以及褐藻糖胶SL45F、SL60F和SL75F,并通过红外光谱、高效液相色谱、凝胶渗透色谱-多角激光光散射仪联用和核磁共振氢谱等技术对多糖的红外光谱特性、单糖组成、分子量及褐藻胶的精细结构等进行了比较分析。结果不同生长期养殖萱藻褐藻胶与褐藻糖胶的产率及结构存在明显的差异,生长期从45d到75d,褐藻胶产率由12.1%(SL45A)提高到22.5%(SL75A),褐藻糖胶产率由1.8%(SL45F)提高到5.8%(SL75F)。两类多糖的分子量均随生长期延长而降低。褐藻胶的细微结构也发生明显的变化,G/M比从2.88(SL45A)下降到1.50(SL75A),褐藻糖胶的单糖组成中葡萄糖比例随生长期延长增加,岩藻糖比例则随生长期延长而降低。结论生长期对养殖萱藻褐藻胶与褐藻糖胶的产率、单糖组成、分子量和精细结构均有显著的影响,选择合适的采收时间对养殖萱藻多糖的结构有非常重要的影响。

Objective To extract and isolate alginates and fucoidans from cultured Scytosiphon lomentarius in different growing stages,analyze their structures,and understand the effect of growth stages on alginates and fucoidans structure.Methods Three alginates and three fucoidans,named SL45 A,SL60A and SL75 A,SL45F,SL60 Fand SL75F,were extracted from cultured Scytosiphon lomentarius in different growing stages（45、60and 75d）of Dalian sea area by 2% Na2CO3 solution in 80 ℃ and precipitated by dilute hydrochloric acid,respectively.Their infrared spectrometry,monosacchrides composition,molecular weight and fine structures were analyzed by infrared spectroscopy,high performance liquid chromatography,gel permeation chromatography-multiangle laser light scatter and proton nuclear magnetic resonance（1 H-NMR）.Results There were obvious differences in yields and structures of alginates and fucoidans among different growth stages from cultured Scytosiphon lomentarius.Growth stages from 45 days to 75 days,the yield of alginates had increased from 12.1%（SL45A）to 22.5%（SL75A）,the yield of fucoidans had increased from 1.8%（SL45F）to 5.8%（SL75F）.The molecular weight of the two kinds of polysaccharides decreased with the increase of the growth stages.The fine structure of the alginate also occurred obvious changes,ratio of G/M decreased from 2.88（SL45A）to1.50（SL75A）.With the extension of the growing stage,and the ratio of glucose increased,the ratio of fucose decreased for monosaccharide composition of fucoidans.Conclusion There were significant effects of growth stages on yield,monosaccharide composition,molecular weight and fine structure of alginates and fucoidans.So the appropriate harvest time had a very important influence on structure of polysaccharides from cultured Scytosiphon lomentarius.