Preliminary Study On Extraction,purification And Functional Activity Of Polysaccharides From Typha Angustifolia

Typha angustifolia is a kind of nutrient-rich edible vegetable.It has been planted for more than 3,000 years in China,which is used in Traditional Chinese medicine to remove pathogenic heat from blood and induce diuresis to alleviate edema.However,the extraction,purification,primary structural analysis and functional activity of the polysaccharides of T.angustifolia have hardly been reported.In this study,the crude polysaccharides of T.angustifolia(PTA)were extracted and purified,and the primary structures of purified polysaccharides were identified,the antioxidant activities and the anti-inflammatory activities of purified polysaccharides were evaluated.This study will provide a scientific basis for the development and utilization of polysaccharide of T.angustifolia.1.Study on extraction and isolation of polysaccharides from T.angustifoliaIn this study,the crude polysaccharide(PTA)was extracted from T.angustifolia,the deproteinization and decolorization process of PTA was optimized,and a novel deproteinization and decolorization method was developed,which is called chelating resin method.Based on single-factor experiments,the optimal conditions were obtained and used for the comparison of chelating resin method with Sevag method.The results showed that chelating resin method exhibited a higher deproteinization ratio(Dr%),decolorization ratio(Cr%),recovery ratio(Rr%)and comprehensive adsorption effect index(ξ).Moreover,the proposed chelating resin method does not consume any toxic organic reagents.Meanwhile,no significant differences in the monosaccharide composition,characteristic functional groups and molecular weight degradation of PTA were observed between the proposed method treatment and the Sevag method treatment.The results suggest that chelating resin method doesn’t damage the structure of PTA and is promising for the deproteinization and decolorization of polysaccharides.2.Purification,physical and chemical properties determination and primry structureanalysis of PTAIn this study,DEAE-52 cellulose Chromatography was used for the purification PTA.Two purified polysaccharides were obtained,that is neutral polysaccharide PTA-1 and acid polysaccharide PTA-2.The contents of total sugar,protein and uronic acid were respectively determined.The results showed that the protein content of PTA-1 was 3.66%,the total sugar content was 94.85%,and the content of uronic acid was not detectable.The protein content of PTA-2 was not detectable,the total sugar content was 94.37%,the content of uronic acid was4.32%.The primary structures of PTA-1 and PTA-2 were preliminarily obtained.The molecular weight of PTA-1 is 87619 Da,and it is glucan composed of α-furan glucose residues.The main chain is composed of(1→3)glycosidic bonds.The molecular weight of PTA-2 is 80853 Da,and it is composed of β-pyran glucose(66.7%)and β-pyran rhamnose(33.3%).The main chain is composed of(1→3)glycosidic bonds.3.Preliminary study on the functional activity of PTAIn this study,the hydroxyl radical scavenging activities and the ferrous ion chelating activities of PTA,PTA-1 and PTA-2 were determined.The results showed that there was a good dose-effect relationship between the hydroxyl radical scavenging activities and the concentrations of PTA,PTA-1 and PTA-2.The hydroxyl radical scavenging activity of PTA-2was stronger than that of PTA-1.PTA-1 and PTA-2 both showed strong ferrous ion chelating activities and there was no significant difference between the two.PTA-2 showed stronger antioxidant activities in vitro,thus the anti-inflammatory activity of PTA-2 was then determined.The results showed that after PTA-2 intervention(50,100 and 200 μg/m L),there was no significant influence on RAW264.7 cell viability;After 200 μg/m L of PTA-2 intervention,the expression levels of IL-6 were significantly decreased,PTA-2(100 and 200 μg/m L)also significantly reduced the levels of TNF-α in a dose-dependent manner;PTA-2(50,100 and 200μg/m L)inhibited the activation of NF-κB in a dose-dependent manner;PTA-2 intervention(100and 200 μg/m L)significantly inhibited the expression of ROS.These results showed that PTA-2has strong anti-inflammatory activity.