Wang Hongyuan, Jiang Xiaolu, Mu Haijin, Liang Xiaoting, Guan Huashi
Medical College, Ocean University of China, Qingdao, PR, 266003, China.
Microbiol Res. 2007;162(2):124-9. doi: 10.1016/j.micres.2006.01.011. Epub 2006 Mar 31.
The water-soluble exopolysaccharide (WSEPS) from Pantoea agglomerans strain KFS-9 isolated from mangrove forest was prepared by removing bacterial cell from the fermentation liquid following by concentration and cold ethanol precipitation of the supernatant. The polysaccharide material was purified by gel permeation chromatography on a Sephacryl S-300HR column and characterized using chemical and spectral methods. The results show that WSEPS is protein-bound polysaccharide, and it is composed of arabinose, glucose galactose and gulcuronic acid in the molar ratio of 1.0:2.2:2.8:0.9. Their antioxidant activities in vitro were studied by various antioxidant assays, including hydroxyl radical scavenging, superoxide radical scavenging and antilipid peroxidation. The results show that the WSEPS extracted had a high antioxidant activity in a concentration-dependent manner (except the activity of antilipid peroxidation). WSEPS quenched hydroxyl radicals, superoxide radicals at low amounts, the IC(50) of which were 0.07 and 0.15 mg/ml, respectively. These results indicate that the protective effect of WSEPS against UV radiation is most likely to be due to the free radicals-scavenging ability.
从红树林中分离得到的成团泛菌KFS-9菌株所产的水溶性胞外多糖（WSEPS），其制备方法是先从发酵液中去除细菌细胞，然后对上清液进行浓缩和冷乙醇沉淀。多糖物质通过在Sephacryl S-300HR柱上进行凝胶渗透色谱法纯化，并采用化学和光谱方法进行表征。结果表明，WSEPS是一种结合蛋白的多糖，由阿拉伯糖、葡萄糖、半乳糖和古洛糖醛酸以摩尔比1.0:2.2:2.8:0.9组成。通过各种抗氧化实验，包括羟自由基清除、超氧阴离子自由基清除和抗脂质过氧化实验，研究了它们的体外抗氧化活性。结果表明，所提取的WSEPS具有高抗氧化活性，且呈浓度依赖性（脂质过氧化抑制活性除外）。WSEPS能清除少量的羟自由基和超氧阴离子自由基，其IC(50)分别为0.07和0.15 mg/ml。这些结果表明，WSEPS对紫外线辐射的保护作用很可能归因于其自由基清除能力。
