| Spirulina platensis is an ancient lower prokaryotic plant.Researches showed that there were abundant bioactive substances in Spirulinaplatensis,such as,protein,polysaccharide,unsaturated fatty acid and so on.Polysaccharide is one of the most important active substances in Spirulina platensis.Spirulina platensis polysaccharide has biological activities such as improving human immunity,anti-inflammatory,anti-tumor and anti-oxidation.Spirulina platensis polysaccharide has wide application prospects in medicine,biology and food.Due to the complicated extraction process,the workload is heavy,the cost of extraction is high,and so the variety and quantity of polysaccharide products has been unable to meet the real need of consumers.This study mainly introduced the extraction of polysaccharide from Spirulina platensis.A pilot production line of Spirulina platensis polysaccharide was established by previous laboratory.The crude polysaccharide of Spirulina platensis was further separated and purified to obtain two polysaccharides,the basic structure and biological activity of these two polysaccharides were studied simultaneously.The main research results are as follows:(1)The condition of crude polysaccharide extraction using alkali leaching method is optimized,and the best extraction condition is as follows:extraction temperature 80℃,alkali concentration 1.25%,extraction time 3h,material-liquid ratio 1:20.Two methods of deproteinization were compared that the polysaccharide yield is 6.33±0.15%by Sevag method,and the yield of polysaccharide is 7.55±0.13%by the combined process of isoelectric point precipitation and ion exchange resin separation technology.In conclusion,the hot alkali leachingisoelectric point protein removal-column chromatography method was determined as the basic process method of the pilot experiment.The experiment built the crude polysaccharides pilot production line consisting of a pretreatment wall breaking unit,a filtration-concentration unit,a column chromatography purification unit and a finished product drying preparation unit.(2)The Spirulina platensis crude polysaccharide(SP)was purified by DEAE-52 cellulose and Sephadex G-100 chromatography column to obtain PSP-1 and PSP-2,and their structures were identified by spectral analysis and physicochemical data.The results showed that the purity of SP,PSP-1 and PSP-2 were 73.80±0.98%,96.54±0.18%and 95.10±0.23%respectively;SP,PSP1 and PSP-2 had a little protein,which were 1.93±0.021%,0.17±0.015%and 0.38±0.26%respectively;SP,PSP-1 and PSP-2 had a little sulfate,which were 2.07±0.31%,0.57±0.14%and 1.05±0.19%respectively.The composition analysis of PSP-1 and PSP-2 by HPLC,FI-IR and NMR showed that PSP-1 and PSP-2 were linear dextran,and their structures were(1→4)-linkedα-D-Glcp as the main chain,and C-6 replaced the single α-D-Glcp as the linear structure of the branch chain.(3)The biology activity SP,PSP-1 and PSP-2 were studied.The SP had certain DPPH radical scavenging ability;The PSP-1 and PSP-2 showed strong xanthine oxidase inhibitory activity.Simultaneously measuring the effects of various components on the cell proliferation ability of LO2 and HepG2,it was found that SP,PSP-1 and PSP-2 had no effect on the cell proliferation ability of LO2.Besides SP could be significant Inhibit the proliferation of liver cancer cells HepG2.The polysaccharide can significantly improve the phagocytic ability of macrophage RAW264.7 and stimulate the phagocyte to produce No.As well as the secretion of NOS and IL-6 related factors and the expression of related genes.The research results show that Spirulina platensis polysaccharides can be applied to the development and utilization of new functional foods,and laid the foundation for the comprehensive utilization of Spirulina platensis. |
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