Isolation And Purification Of Polysaccharides From Dendrobium Huoshanense And Their Probiotic Effects

Dendrobium huoshanense is an orchid plant with high medicinal value.It mainly contains polysaccharides,amino acids,polyphenols,alkaloids,flavonoids and other active ingredients.Modern pharmacological studies have proved that Dendrobium huoshanense polysaccharide has the functions of improving immunity,preventing and treating diabetes mellitus,antioxidant,antiviral,anti-tumor,anti-bacterial and anti-inflammatory.In this paper,three main polysaccharide components were isolated and purified from Dendrobium huoshanense polysaccharide,and their effects on the physiological activity of lactic acid bacteria were studied.The most significant component DHP1-2,which promoted the growth of lactic acid bacteria,was obtained.The structure and composition of the polysaccharide component DHP1-2 were analyzed and studied.Later,the beneficial life of the polysaccharide component DHP1-2 was further studied.The main research contents are as follows:1.Isolation and purification of Polysaccharides from Dendrobium huoshanenseCrude polysaccharides were extracted from dried Dendrobium powder by water extraction,alcohol precipitation,deproteinization and decolorization.Then,three main polysaccharides were purified by DEAE-52 cellulose anion exchange column and agarose CL-6B gel column,named DHP1-2,DHP2-1 and DHP2-2,respectively.The recoveries of DHP1-2,DHP2-1 and DHP2-2 were 98.3%,25.43%and 70.3%,respectively.The viability of three main polysaccharides,DHP1-2,DHP2-1 and DHP2-2,was preliminarily studied.The results showed that DHP1?2 had the most obvious effect on the growth of Lactobacillus acidophilus.Preliminary determination of the most beneficial components of DHP1-2.2.Study on the Composition and Structure of DHP1-2Ultraviolet spectroscopy showed that the polysaccharide component DHP1-2 had no absorption peak at 260-280 nm,indicating that there were no impurities such as nucleic acid and protein in DHP1-2.Infrared detection showed that DHP1-2 contained O-H,C-H,C=O,C-O-C and C-O-H chemical bonds,and contained mannose pyranose-oxime bonds with beta-configuration.The molecular weight of DHP1-2 was 1080Da determined by high performance gel filtration chromatography(GPC).Analysis of monosaccharide components by liquid phase chromatography showed that the main polysaccharide component DHP1-2 was composed of glucose,galactose,mannose and arabinose,accounting for 95.37%?1.78%?0.8%and 0.6%of the polysaccharide component DHP1-2,respectively.Nuclear magnetic spectrum analysis showed that DHP1-2was mainly composed of beta-configuration glycoside bonds.3.Effect of DHP1-2 on physiological activity of lactic acid bacteriaThe effects of DHP1-2 on biomass,reducing sugar utilization,protein synthesis,acid production and extracellular polysaccharide synthesis of Lactobacillus acidophilus and Lactobacillus casei were studied.The results showed that DHP1-2 could promote the proliferation of Lactobacillus acidophilus,increase the utilization efficiency of carbon sources by probiotics,promote the synthesis of protein in cells,increase the acid production of Lactobacillus acidophilus and synthesis of extracellular polysaccharides.Power.The anti-digestion experiment of simulated gastric juice showed that the maximum hydrolysis rate of DHP1-2 was only 3.12%,while that of alpha-amylase was only 4.91%.It indicated that DHP1-2 had strong anti-digestion ability and could be used by probiotics in intestine.The scavenging rates of DHP1-2 on ABTS and DPPH free radicals were 73.5%and 75%,respectively.The results showed that DHP1-2 had good antioxidant activity.