Extraction,Purification,physicochemical Properties And Biological Activity Research Of Polysaccharides From Eriobotrya Japonica Leaf

Eriobotryajaponica leaf is a traditional Chinese herbal medieine which is mainly distributed in south China,Shanxi,Gansu and Taiwan.It has long been used to eliminate phlegm,treat coughs and yin deficiency.Currently,the study of loquat leaf most focused on active constituents,etc,But little information is available about the structure of homogeneous polysaccharide of Eriobotrya japonica leaf(PEL),much less,the polysaccharide isolated from this plant.There are four parts in this research including determination of optimum extraction conditions of ultrasound-assisted technology of PEL,separation and purification,physicochemical property research,and the biological activity research.The response surface method was used to obtain the optimal process conditions for ultrasonic extraction of PEL,the conditions were confirmed:the ratio of water to material 21,ultrasonic power 380 w,extraction time 42 min,and the PEL extracting yield reached 3.62%under the conditions,so it could effectively improve the efficiency of the loquat leaf polysaccharide extraction.After alcohol precipitation PEL30,PEL60 and PEL80 were obtained.Two water-soluble polysaccharides PEL60A and PEL80A were purified and obtained by using DEAE Sepharose fast flow anion-exchange chromtography and Sephacryl S gel-filtration chromatography from PEL60 and PEL80.HPLC producing a single symmetrical peak indicated PEL60A was homogeneous and its molecular weight was 296 kDa.Lack of absorption at 280 nm and 260 nm by UV scanning indicated that they contained no protein and nucleic acid.The infrared spectrum of PEL60A displayed a broad stretching intense characteristic peak of polysaccharide and indicated it has furan and pyranoside configurations.Sugar compositional analysis of PEL60A was determined by GC-MS.Comparison with the analysis of mixture of monosaccharide standard showed that PEL60A was composed of rhamnose,arabinose and maybe little xylose,galactose,their mole ratio was 0.70:1.00:0.19:0.29.The structure of PEL60A was further investigated by using NMR spectroscopic methods(1H NMR,13C NMR).The results showed that it contains α-arabinose and β-rhamnose configuration;it may contains acetyl structure.PEL applied research focus on three sections:the study of PEL antioxidant activity showed that PEL possesses better antioxidant activity,and its reducing capacity,DPPH-scavenging capacity and ABTS radical scavenging activity were increased after sulfated modification;Antitumor activity research showed that PEL could effectively inhibit lung adenocarcinoma cells(A549)growth in vitro,and nearly non-toxic side effects on the normal cells;The study on the application of cigarette showed:PEL could reduce the loss of tobacco moisture,and be used as a new type of tobacco humectant.