Microwave-Assisted Degradation of Polysaccharide from Polygonatum sibiricum and Antioxidant Activity.

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 (Fe2+ and Cu2+ 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 × 105 to 2.33 × 103 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.

Zhang H ，Cai XT ，Tian QH ，Xiao LX ，Zeng Z ，Cai XT ，Yan JZ ，Li QY ... -  《-》

Effect of steaming process on the structural characteristics and antioxidant activities of polysaccharides from Polygonatum sibiricum rhizomes.

Polygonatum sibiricum (P. sibiricum) rhizomes are widely used as a tonic and functional food, and are often processed to enhance their tonic function by repeated steaming and drying. As the most important constituent, the polysaccharide from P. sibiricum rhizomes (PSP) has demonstrated various activities, but the alteration of structural characteristics and activities of the purified PSPs during steaming process was rarely investigated. To well understand the effect of steaming process on the polysaccharides of P. sibiricum, neutral polysaccharides from P. sibiricum rhizomes (PSP0 ~ PSP9) after steaming were first isolated and purified, and then the chemical properties and antioxidant activities were determined. The results showed that the molar ratios of monosaccharides in PSPs were different. The molecular weights of PSPs were increased significantly after the fourth steaming. Morphological studies showed that the surface of PSPs became much tighter during the steaming process. Fourier transform infrared spectroscopy spectra displayed the polysaccharides had similar backbones and chemical groups. Furthermore, the antioxidant activity of PSPs was measured through radical scavenging tests. It was found that the radical scavenging activity of PSPs was elevated strikingly after steaming, and increased gradually with numbers of steaming process. The biological and chemical variance of PSPs revealed considerable segregation of PSP0, PSP1 ~ PSP4 and PSP5 ~ PSP9. In conclusion, our results proposed the fourth time as the optimal number of steaming to extract functional polysaccharide from P. sibiricum rhizomes.

Li Q ，Zeng J ，Gong P ，Wu Y ，Li H ... -  《-》

Extraction, characterization and antioxidant activities of polysaccharides of Chuanminshen violaceum.

A single factor experiment and Box-Behnken design were applied to optimize the microwave-assisted extraction (MAE) of Chuanminshen violaceum polysaccharides (CVPs). The CVPs yield was 34.59 ± 0.51%, which was in accordance with the predicted value of 35.54%, under the following optimum conditions: microwave power of 466 W, extraction temperature of 64.5 °C, extraction time of 15 min, and water-raw material ratio of 40 mL/g. Two CVPs fractions (CVPs-I and CVPs-II) were obtained via stepwise ethanol precipitation. CVPs-II was further purified using DEAE cellulose-52 chromatography to obtain the major fraction of CVPs-IIa. Fourier transform infrared spectroscopy (FTIR) and GC-MS analysis revealed that crude CVPs, CVPs-I, and CVPs-II were neutral polysaccharides and were mainly composed of glucose and galactose. The molecular weights of CVPs-I and CVPs-IIa were 233.69 and 11.02 kDa, respectively. Furthermore, all samples exhibited certain antioxidant activity or reducing power to scavenge the DPPH and ABTS radicals, among which CVPs-II was the strongest. In conclusion, MAE is an efficient method for extracting CVPs of C. violaceum, and this plant root has the potential to be explored as a source of natural antioxidants.

Dong H ，Zhang Q ，Li Y ，Li L ，Lan W ，He J ，Li H ，Xiong Y ，Qin W ... -  《-》

Structural characterization and antioxidant activity of Polygonatum sibiricum polysaccharides.

Polysaccharide is one of the main active components of Polygonatum sibiricum. For this study, P. sibiricum polysaccharides (PSP) were obtained through purification using DEAE-Cellulose52 and Sephacryl G-150 column chromatography. The obtained samples were named PSP1, PSP2 and PSP3. The PSP1 sample was found to have the highest content and the best solubility, and a subsequent. So, its structure and characterization were analyzed. The main sugar residue linkages were found to be → 1)-β-D-Fruf-(2 → 1)-β-D-Fruf-(2 → 1), 1 → -β-D-Fruf-(2 → 6)α-D-Glcp (1→, →4)-β-D-Manp-(1 → 4)-β-D-Manp-(1→ and →6)-β-D-Glcp-(1 → 4)-β-D-Manp-(1→ link existed. Branch chain analysis indicated →1,6)-β-D-Fruf-(2→, β-D-Fruf-(2→, →1,6)-β-D-Fruf-(2→, →6)-β-D- Fruf-(2→ link existed, and the link site was at position C-6. In vitro antioxidant activity tests showed that PSP1 had a certain scavenging effect on DPPH, hydroxyl radical, superoxide anion radical and a particular effect on the chelating ability of ferrous. This suggested that P. sibiricum polysaccharides may be a potential antioxidant.

Wang S ，Li G ，Zhang X ，Wang Y ，Qiang Y ，Wang B ，Zou J ，Niu J ，Wang Z ... -  《-》

[Determination of relative molecular mass and composition for Polygonatum sibiricum polysaccharide by high performance liquid chromatography].

Zhang X ，Gereltu B ，Zhaorigetu ，Narisu ... -  《-》