小分子Rhizobium sp. N613胞外多糖的制备及其抗肿瘤活性

Preparation and anti-tumor activity of low molecular weight exopolysaccharide from Rhizobium sp. N613

摘要:

采用微波辐照氧化技术, 降解大分子Rhizobium sp. N613胞外多糖(REPS)为小分子多糖(LREPS), 以改善其理化及抗肿瘤活性, 提高应用价值和拓展应用范围。通过正交试验考察了底物浓度、H2O2浓度、微波辐照强度和辐照时间对降解产物分子量的影响并获得一系列LREPS产物。选取4组分子量段(10以下、10、20和30 kD左右)的LREPS代表性样品进行小鼠体内S180抑瘤效果检测, 其中分子量段为10.352 kD的LREPS效果最佳, 抑瘤率高达52.8%, 确定为LREPS的最适分子

Abstract:

Exopolysaccharide from Rhizobium sp. N613 (REPS) was degraded by microwave irradiation with H2O2 to improve its physical, chemical and anti-tumor activity. Effects of REPS’s concentration, H2O2’s concentration, intensity and time of microwave irradiation on the molecular weight of degradated products were investigated by orthogonal test. Then the antitumor activities of four different molecular weight of LREPS were evaluated in mice bearing sarcoma 180. The results indicated that inhibition rate reached 52.8% when the molecular weight of LREPS reduced to 10.352 kD. LREPS(10.352 kD)’s preparation conditions were as follows: REPS’s concentration was 2 g/L, H2O2’s concentration was 6%, radiation intensity was 375 W, and irradiation time was 2 min. The molecular structure of the LREPS was analyzed by IR. The result indicated that LREPS was a β-glucan. The solubility of LREPS was increased from 8 g/L to 15.73 g/L, and the intrinsic viscosity of LREPS was reduced from 527.64 mL/g to 351.67 mL/g. The technology of preparing LREPS was established. Moreover, relevant technical parameters were obtained. Results of these study lay a certain foundation for the production and application of the polysaccharide.