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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的最适分子量段。其制备工艺条件为:REPS浓度为2 g/L、H2O2浓度为6%、微波辐照强度为375 W、微波辐照时间为2 min;理化分析结果表明,LREPS的红外图谱与REPS相似,仍为β-D-吡喃葡聚糖。其溶解度由原多糖的8.00 g/L增至15.73 g/L,特性粘数由原多糖的527.64 mL/g降至351.67 mL/g。建立了LREPS制备工艺并获取了相关理化及抗肿瘤技术参数,为该多糖制剂的生产应用奠定一定基础。
Microwave radiation oxidation was used to degrade the macromolecular Rhizobium sp. N613 extracellular polysaccharide (REPS) as small molecule polysaccharide (LREPS) to improve its physico-chemical and antitumor activity, increase its application value and expand the application range. The effects of substrate concentration, H2O2 concentration, microwave irradiation intensity and irradiation time on the molecular weight of degradation products were investigated by orthogonal experiments. A series of LREPS products were obtained. Four representative LREPS samples with molecular weight below 10, 10, 20 and 30 kD were selected to test the antitumor effect of S180 in mice. LREPS with the molecular weight of 10.352 kD showed the best effect and the tumor inhibition rate was as high as 52.8% , Identified as the LREPS optimal molecular weight segment. The preparation conditions were: REPS concentration of 2 g / L, H2O2 concentration of 6%, microwave irradiation intensity of 375 W, microwave irradiation time of 2 min; physical and chemical analysis showed that the LREPS infrared spectra and REPS similar Is β-D-glucan. Its solubility increased from 8.00 g / L of original polysaccharide to 15.73 g / L, and intrinsic viscosity decreased from 527.64 mL / g of original polysaccharide to 351.67 mL / g. The preparation process of LREPS was established and the related technical parameters of physicochemical and antitumor were obtained, which laid the foundation for the production and application of polysaccharide preparation.