College of Pharmaceutical Science, Zhejiang Univ. of Technology, Hangzhou, 310014, China.
Collaborative Innovation Center of Yangtze River Region Green Pharmaceuticals, Zhejiang Univ. of Technology, Hangzhou, 310014, China.
J Food Sci. 2019 Apr;84(4):754-761. doi: 10.1111/1750-3841.14449. Epub 2019 Mar 25.
Four polysaccharide fractions (P-1: 71.40%, P-2: 1.95%, P-3: 1.14%, P-4: 1.64%) were isolated from crude Polygonatum sibiricum polysaccharide (PSP), processed by water extraction, ethanol precipitation, and further separated with diethylaminoethyl cellulose-52 anion-exchange chromatography. Their molecular weights and monosaccharide compositions were characterized by high performance gel chromatography with evaporative light scattering detector and ultraviolet-visible detector. The antioxidant activity of four polysaccharides fractions were assessed by the electron transfer menchanism (DPPH, ferric reducing power, and ABST assays) and chelation of transition metals (Fe and Cu chelation ability). The highest content fraction P-1 exhibited the lowest antioxidant activity, and the ranking of antioxidant capacity was P-4 > P-3 > P-2 > PSP > P-1. After processed by microwave-assisted degradation, the molecular weight of P-1 was decreased from 2.99 × 10 to 2.33 × 10 Da, while the antioxidant activity of degraded P-1 was about eightfold higher than natural P-1. These results indicated that the proposed microwave-assisted degradation approach was an efficacious methodology to improve their bioactivity by lower the molecular weight of polysaccharides. PRACTICAL APPLICATION: This study provided an environmentally friendly, convenient and efficient microwave-assisted degradation technology to process the neutral polysaccharides from Polygonatum sibiricum. The results could be used for the development and utilization of various plant polysaccharides as a kind of food supplement in our daily life.
四种多糖级分（P-1：71.40%、P-2：1.95%、P-3：1.14%、P-4：1.64%）从粗西伯利亚黄精多糖（PSP）中分离得到，经过水提、乙醇沉淀和进一步用二乙基氨基乙基纤维素-52 阴离子交换色谱分离得到。它们的分子量和单糖组成通过高效凝胶色谱法与蒸发光散射检测器和紫外-可见检测器进行了表征。四种多糖级分的抗氧化活性通过电子转移机制（DPPH、铁还原能力和 ABST 测定）和过渡金属螯合（Fe 和 Cu 螯合能力）进行评估。抗氧化能力最高的级分 P-1 表现出最低的抗氧化活性，抗氧化能力的排序为 P-4 > P-3 > P-2 > PSP > P-1。经微波辅助降解后，P-1 的分子量从 2.99×10 降低到 2.33×10 Da，而降解的 P-1 的抗氧化活性约比天然 P-1 高八倍。这些结果表明，所提出的微波辅助降解方法是一种通过降低多糖分子量来提高其生物活性的有效方法。实际应用：本研究提供了一种环保、方便、高效的微波辅助降解技术，用于处理黄精中的中性多糖。研究结果可用于开发和利用各种植物多糖作为日常生活中的一种食品补充剂。
