Extraction, Structure, Antioxidant And Antiaging Activity Of Polysaccharides And Their Degradation Products By Lentinus Edodes SD-08

Lentinus edodes, an edible mushroom also known as mushrooms and shiitake, is an edible mushroom. It belongs to Eumycophyta, Pleurotaceae, Lentinus. Lentinus edodes. L. edodes was the second most popular edible mushroom in the world. The biological activity of lentinan which extract from fermentation broth and mycelium are mainly including antioxidant, anti-aging, anti-tumor, hypoglycemic, hypolipidemic, anti-fatigue and enhance the immunity.Zinc is one of the essential trace elements for human body, and as the most important component of many enzymes, it plays an important role in growth and development, recognition memory, maintaining the integrity of the cell and the biosynthesis of protein and nucleic acid. But there is low-level-zinc in our daily diet structure, and the zinc can not be synthesized in vivo, therefore, cultivating this mushroom will benefit food provision and recycling of agricultural by-products.the culture conditions of Zn-accumulated by Lentinus edodes SD-08In this paper, the extraction conditions of L. edodes SD-08 extracellular polysaccharides(EPS), mycelia polysaccharides(MPS) and mycelia Zinc polysaccharide(MZPS) in submerged culture were optimized on the basis of Plackett-Burman(PB) design and response surface methodology(RSM) in this paper. The chemical structure, molecular weight and the antioxidant activities in vitro and antiaging activities were determined. The antioxidant activities in vitro of the components of EPS, MZPS and their hydrolysate and enzymatic hydrolysis products(EEPS、SEPS、EMZPS、SMZPS) were also determined.(1) The optimal conditions of EPS and MZPS extractionThe three most significant factors influence on the amount of lentinan extraction were determined by PB experiments. RSM result shows that extraction of the theoretical amount of EPS and MZPS were 2.74g/L and 1.480%, in their optimum extraction conditions respectively. The results showed that the actual yields of EPS and MZPS were 2.75g/L and 1.48% respectively.(2) Isolation and purification of EPS and MZPSAfter DEAE-cellulose ion exchange separation column, EPS obtain component EPS-1 and EPS-2, MPS obtain component MPS-1 and MPS-2, MZPS obtain component MZPS-1 and MZPS-2, EEPS obtain component EE-1 and EE-2, SEPS obtain component SE-1, EMZPS obtain component EP-1 and EP-2, SMZPS obtain component SP-1, respectively.(3) The in vitro antioxidant of lentinan and the fractionsThe reducing powers of EPS, EEPS and SEPS at the dosage of 1000mg/L were 0.44±0.03, 1.13±0.001 and 1.19±0.05. The in vitro inhibition effects on hydroxyl radicals were 93.64±1.25%, 99.87±1.12% and 73.47±3.64%, and on DPPH radicals were 15.93±0.13%, 97.21±0.57% and 60.73±2.01%. At the dosage of 100mg/L, the reducing power of EPS-1、EPS-2、EE-1、EE-2 和 SE-1 were 0.25±0.02, 0.77±0.01, 0.22±0.03, 0.26±0.01 and 0.19±0.01, the scavenging effects on hydroxyl radicals were 46.08±0.02%, 39.70±0.01%, 10.13±0.03%, 89.01±0.01% and 19.28±0.01%, and the scavenging effects on DPPH were 12.02±0.02%、8.28±0.01%、16.21±0.03%、17.87±0.01% and 67.28±0.01%, respectively. The in vitro results showed that the antioxidant activity of EPS after enzymatic and acid of hydrolysis were improved, and the antioxidant activity of the components was obviously higher than that of raw polysaccharide at same concentration.The reducing powers at 700 nm of MPS, MZPS, EMZPS and SMZPS at the dosage of 1000mg/L were 0.14±0.03、0.77±0.001、0.52±0.05 and 0.31±0.03. The in vitro inhibition effects on hydroxyl radicals were 58.99±1.03% 、 66.20±1.34% 、 78.58±2.33% and 92.10±2.57%, and on DPPH radicals were 13.77±0.37%,77.33±0.28%,52.79±0.58% and 31.08±0.87%. At the dosage of 100mg/L, the reducing power of MZPS-1、MZPS-2、EP-1、EP-2 and SP-1 were 0.03±0.02、0.04±0.01、0.49±0.03、0.50±0.01 and 0.38±0.01, the scavenging effects on hydroxyl radicals were 34±0.02%、10.63±0.01%、22.04±0.03%、19.22±0.01% and 25.14±0.01%, and the scavenging effects on DPPH were 4.98±0.02%、9.97±0.01%、13.39±0.03%、22.03±0.01% and 13.90±0.01%, respectively. The in vitro results showed that the antioxidant activity of MPS and MZPS after enzymatic and acid of hydrolysis were improved, and the antioxidant activity of the components was obviously higher than that of raw polysaccharide at same concentration.(4) Anti-aging activity of lentinan in vivoThe results showed that EPS, MPS and MZPS promoted the level of T-AOC, the activity of SOD, GSH-Px and reduced the content of MDA in blood and tissue cells. Compared with the model group, the results of the test group polysaccharide reached a significant level, indicating EPS, MPS and MZPS have a strong anti-aging activity, and the activity of MZPS was higher than that of MPS.(5) Monosaccharide composition and molar ratio of lentinanEPS, MPS and MZPS were determined their monosaccharides composition and molar ratio by GC. The result showed that EPS was constituted with rhamnose, arabinose, mannose and glucose, and their molar ratio was 2.7:1.0:2.9:1.8; MPS was constituted with r rhamnose, arabinose, mannose, and their molar ratio was 1.7:1.0:3.0; MZPS was constituted with rhamnose, mannose and glucose, and their molar ratio was 7.2:2.3:1.0:8.4.(6) Chemical structure determination of lentinanEPS and MZPS were scaned by IR in the 4000-400cm-1 section, the result showed that they were D- pyranoid.(7) Molecular weight determination of lentinanThe Mn(number-average molecular weight), Mw(weight-average molecular weight), and the Mw/Mn value of EPS were 5.32×102, 3.58×104 and 67.26, and the Mn, Mw, and the Mw/Mn value of MZPS were 7.14×102, 1.20×105 and 168.19.