中文摘要：

羊栖菜(Sargassumfusiforme)是一种有“长寿菜”美誉的经济藻类,其中的多糖成分具有良好的抗氧化活性。本文依次用冷水和热水处理羊栖菜藻粉,得到两种多糖:冷水浸提多糖(SFCP)和热水煮提多糖(SFHP);随后对这两种多糖的理化性质进行比较,并通过测定二者对DPPH和羟自由基的清除能力评价其抗氧化活性。结果表明,两种多糖都是含有硫酸根的岩藻聚糖,但是SFCP中糖醛酸含量较高,分子质量分布集中,而SFHP中硫酸根含量较多,分子质量分布较宽,且二者硫酸根取代位置不同。两种多糖对DPPH和羟自由基均有一定的清除效果,且清除率与浓度存在剂量依赖关系。相比较而言,SFCP对自由基的清除效率较好。

英文摘要：

Sargassum fusiforme is an alga with economic significance and a good reputation for food longevity. Its polysaccharide also demonstrates good biological activities. In this study, we extracted two polysaccharide fractions-S. fusiforme cold-water-extracted polysaccharide (SFCP) and S.fusiforme hot-water-extracted polysaccharide (SFHP)-from S. fusiforme with water at 4℃ and 80℃, successively. We determined the physicaland chemical properties of the polysaccharide fractions and evaluated their anti-oxidative activities by the radical scavenging ratios of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free and hydroxyl radicals. The results show that thetwo polysaccharide fractions were both fucosan with sulfate. SFHP showed a wider molecular weight distribution than SFCP and contained more sulfate, whereas SFCP contained more uronic acid. Their sulfate radical substitution positions also differed. SFHP and SFCP demonstrated certain dose-dependent activities for scavenging DPPH and ·OH. SFCP demonstrated better efficiency in removing free radicals.