Study On Polysaccharide Components And Antioxidant And Antibacterial Activities Of Commodity Brasenia Schreberi From Four Production Areas

Brasenia schreberi is a perennial aquatic perennial root herb of the Cabombaceae family,and it is rich in protein,trace elements,mineral elements,dietary fiber and polysaccharides.It has a variety of physiological activities,such as lowering blood lipid,lowering blood glucose and anti-cancer,and it is also a dual-use plant for medicinal and edible,known as "ginseng in water,placenta of plant ".Due to the limited of environment for Brasenia schreberi to grow and the large number of products for export,it is scarce in the domestic market,even few people know about it,So studies on Brasenia schreberi are fewer and fewer.Polysaccharide is one of the main components of Brasenia schreberi with anti-inflammatory,antioxidant and antibacterial activities.It is of great significance to strengthen the study of polysaccharides of Brasenia schreberi for rational utilization and further processing and development of products.The active ingredients of plants are greatly affected by the environmental conditions and production conditions in the producing area.In China,the commercial Brasenia schreberi in the market is mainly from 4 cultivation areas,Shizhu of Chongqing,Lichuan of Hubei,Leibo of Sichuan and West lake in Zhejiang.In this experiment,Brasenia schreberi from four places above-mentioned was used as experimental material.the total sugar content was determined by phenol-sulfuric acid method,and the composition and content of polysaccharide were determined by high performance liquid chromatography（HPLC）.Secondly,the method of DPPH,FRAP and ABTS were used to determine the antioxidant activity of polysaccharide of Brasenia schreberi;At the same time,the disk diffusion method was used to compare the inhibitory activities of polysaccharides against Proteus vulgaris,Escherichia coli,Pseudomonas aeruginosa and Bacillus subtilis;Finally,the effects of total sugars and monosaccharides from different Brasenia schreberi on antioxidant and antibacterial activities were analyzed.The differences of Brasenia schreberi from four places are compared in terms of content and composition of polysaccharide,antioxidant activityand bacteriostatic activity.The main research results are as follows:（1）The content of Brasenia schreberi polysaccharide from four producing areas has regional difference.The content of water-soluble polysaccharide varied in the range of（5.32±0.156）mg·g-1^7.36±0.190mg·g-1,comparison the content of polysaccharide: Brasenia schreberi from Lichuan> Brasenia schreberi from West lake > Brasenia schreberi from Shizhu > Brasenia schreberi from Leibo.The content of alkali-soluble polysaccharides varied in the range of（7.14±0.380）mg·g-1^10.15±0.236mg·g-1,Comparison the content of polysaccharide: Brasenia schreberi from Leibo >Brasenia schreberi from Shizhu> Brasenia schreberi from West lake >Brasenia schreberi from Lichuan.Comprehensive comparison of water-soluble polysaccharides and alkali-soluble polysaccharides: Brasenia schreberi from Leibo > Brasenia schreberi from West lake > Brasenia schreberi from Shizhu> Brasenia schreberi from Lichuan.（2）Based on the analysis of alkali-soluble polysaccharides and water-soluble polysaccharides from four producing areas,the main components are 10 monosaccharides such as mannose,galactose and rhamnose,but the monosaccharide content of the two types of polysaccharides is different.The content of galactose was the highest in water-soluble and alkali-soluble polysaccharides,followed by fucose and mannose.The galactose content of water-soluble polysaccharides was the highest in Shizhu（40.33%）and fucose and mannose in Lichuan（16.30%）respectively.The content of galactose and mannose in alkali-soluble polysaccharides was the highest,39.76% and 16.18% respectively.Fucose in West Lake was higher than that in other areas,accounting for 16.68%.（3）The antioxidant activity of water soluble polysaccharides was stronger than that of alkali soluble polysaccharides.Among water-soluble polysaccharides,the order of comprehensive antioxidant capacity was: Brasenia schreberi from Lichuan>Brasenia schreberi from Shizhu> Brasenia schreberi from Xihu> Brasenia schreberi from Leibo,and the comprehensive APC index of antioxidant was 99.62%,87.42%,84.89% and 79.38%,respectively.Among alkali-soluble polysaccharides,the order of comprehensive antioxidant capacity was: Brasenia schreberi from Leibo> Brasenia schreberi from Shizhu> Brasenia schreberi from Xihu> Brasenia schreberi from Lichuan.The comprehensive APC index of antioxidant was 67.84%,61.73%,55.06%and 51.88%,respectively.Comparing the antioxidant ability of water-soluble polysaccharides and alkali-soluble polysaccharides: Brasenia schreberi from Lichuan >Brasenia schreberi from Leibo > Brasenia schreberi from Shizhu > Brasenia schreberi from Xihu.（4）The polysaccharides from the four producing areas have bacteriostatic activity against Proteus vulgaris,Escherichia coli and Pseudomonas aeruginosa,but have no obvious bacteriostatic effect on Bacillus subtilis.The bacteriostatic activity of water-soluble polysaccharides is stronger than that of alkali-soluble polysaccharides.Among the water-soluble polysaccharides,the order of comprehensive bacteriostasis ability was: Brasenia schreberi from Lichuan> Brasenia schreberi from Shizhu>Brasenia schreberi from West Lake > Brasenia schreberi from Leibo.The comprehensive APC index of bacteriostasis was 94.55%,92.83%,91.11%,81.62%,respectively.Among the alkali-soluble polysaccharides,the order of comprehensive bacteriostasis ability was: Brasenia schreberi from Shizhu> Brasenia schreberi from Leibo> Brasenia schreberi from West Lake > Brasenia schreberi from Lichuan,and the APC index of comprehensive bacteriostasis was 91%,80.42%,75.94% and 74.83%,respectively.The bacteriostatic activities of water-soluble polysaccharides and alkali-soluble polysaccharides were as follows: Brasenia schreberi from Shizhu>Brasenia schreberi from Lichuan> Brasenia schreberi from West Lake> Brasenia schreberi from Leibo.（5）According to the correlation analysis of water-soluble polysaccharide components and their antioxidant and bacteriostatic activities,the main factors that played an important role in DPPH free radical scavenging experiment were polysaccharide content（r=0.784,very significant）,mannose（r=0.822,very significant）,fucose（r=0.965,very significant）,glucuronic acid（r=0.627,significant）.In FRAP iron reduction experiment,the main factors were polysaccharide content（r=0.642,significant）,mannose（r=0.709,extremely significant）,glucuronic acid（r=0.625,significant）,galactose（r=0.607,significant）,fucose（r=0.976,very significant）.In ABTS free radical scavenging experiment,the main factors were mannose（r=0.853,very significant）and xylose（r=0.788,significant）.Polysaccharide content was positively correlated with the inhibition effect of Proteus vulgaris（r=0.837,very significant）;galactose（r=0.690,significant）and fucose（r=0.746,very significant）had strong inhibition effect on Escherichia coli;glucuronic acid（r=0.701,significant）and fucose（r=0.655,significant）had a positive correlation on the inhibition effect of Pseudomonas aeruginosa.From the analysis of the composition of alkali soluble polysaccharides and theircorrelation with antioxidant and bacteriostatic activities,we can see that the main factors in DPPH radical scavenging experiment are polysaccharide content（r=0.872,very significant）,mannose（r=0.819,very significant）,glucuronic acid（r=0.873,very significant）,galactose（r=0.890,very significant）,xylose（r=0.890,very significant）.In FRAP iron reduction experiment,the main factors were polysaccharide content（r=0.933,very significant）,mannose（r=0.723,very significant）,glucuronic acid（r=0.906,very significant）,galactose（r=0.937,very significant）,xylose（r=0.809,very significant）.In the free radical scavenging experiment of ABTS,xylose（r=0.586,significant）,glucuronic acid（r=0.714,very significant）and galactose（r=0.714,very significant）had a positive correlation with the inhibitory effect of Proteus vulgaris.From the above,the commercial Brasenia schreberi from 4 major cultivation areas in China have regional differences in contents of total sugar and monosaccharide.The composition of polysaccharide and its antioxidant capacity and bacteriostatic effect all were different.The research results of this experiment was of great significance for the protection and scientific exploitation of Brasenia schreberi,and It provides theoretical reference for scientific research of Brasenia schreberi.