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目的对来源于南海深海海泥链霉菌Streptomyces pratensis OUCMDZ-3159所产胞外多糖的结构和抗氧活性进行研究。方法利用醇沉法和柱色谱法对菌株所产胞外多糖进行分离纯化,利用多种仪器分析方法,包括PMP柱前衍生高效液相色谱法、红外光谱法和气相质谱联用法等分析了多糖的化学组成和结构,通过测定DPPH自由基清除活性、超氧阴离子自由基清除活性、羟基自由基清除活性和还原能力,对多糖的抗氧化活性进行评价。结果从链霉菌Streptomyces pratensis OUCMDZ-3159发酵液中得到了1种分子量为25.0kDa的多糖组分ZS-11,它是由甘露糖和半乳糖以14.5∶1的比例构成;糖链中包含(1→)-Manp,(1→2)-Manp,(1→3)-Manp,(1→6)-Manp,(1→2,3)-Galf和(1→2,6)-Manp连接方式;多糖ZS-11具有良好的抗氧化活性,在测定的4种活性指标中,清除DPPH自由基的能力最强。结论首次从深海海泥放线菌Streptomyces pratensis OUCMDZ-3159中分离得到抗氧化活性显著的胞外多糖ZS-11,它是1种结构新颖的半乳甘露聚糖。
OBJECTIVE To study the structure and antioxidant activity of exopolysaccharide from Streptomyces pratensis OUCMDZ-3159 in the South China Sea. Methods The ethanol extract and column chromatography were used to separate and purify the exopolysaccharides produced by the strains. The polysaccharides were analyzed by a variety of instrumental analysis methods, including PMP column precolumn derivatization high performance liquid chromatography, infrared spectroscopy and gas chromatography mass spectrometry. The antioxidant activity of polysaccharides was evaluated by measuring the DPPH radical scavenging activity, superoxide anion radical scavenging activity, hydroxyl radical scavenging activity and reducing ability. Results A polysaccharide fraction ZS-11 with a molecular weight of 25.0 kDa was obtained from the fermentation broth of Streptomyces pratensis OUCMDZ-3159. The polysaccharide fraction ZS-11 was composed of mannose and galactose in a ratio of 14.5: (1 → 2) -Manp, (1 → 3) -Manp, (1 → 6) -Manp, (1 → 2,3) -Galf and ; Polysaccharide ZS-11 has a good antioxidant activity, the determination of the four activity indicators, the ability to scavenge DPPH strongest. Conclusions The exopolysaccharide ZS-11 with obvious antioxidant activity was isolated from Streptomyces pratensis OUCMDZ-3159 for the first time. It is a novel galactomannan with novel structure.