Studies On Extraction, Purification And Chemical Of The Polysaccharides From Embryo Of The Seeds Of Nelumbo Nucifera Gaertn

Embryo of the seeds of Nelumbo nucifera gaertn is one of the most important herbs. It has many medical functions, such as reducing the blood pressure,reducing the fever and cardiac. The objective of this dissertation is to study the isolation, physical chemistry property and its analysis methods, and structure of polysaccharides from Embryo of the seeds of Nelumbo nucifera gaertn (ESP). The results are as follows :The primary chemical composition of powder of frozen dried embryo of the seeds of Nelumbo nucifera gaertn were: protein19.2% , crude fat 22.7% , ash 17.3%, moisture 9.4%.Aiming at the extraction of ESP, experiment factors and levels were firstly selected by single-factor tests. Next, on the basis of this and according to the Box-Benhnken center-united experimental design principles, the method of response surface analysis with 3 factors and 3 levels was adopted. Then, the factorsInfluencing the extraction technology were determined by means of regression analysis, and response surface was graphed with the extraction rate of ESP as the response value. The results showed that the optimum conditions were: the extraction temperature of 82.5℃, extraction time of 4.25h, and the ratio of water to material was45:1(v/w). the extraction rate of ESP was up to 10.3 mg/g.The purification and concentration of ESP were carried out via membrane ultrafitration using the membranes with different molecular weight cut-off. The optimum conditions for the ultrafiltration were finally determined. It was found that, for the membrane with a molecular mass cut-off of 5000, when the pressure is 0.20 M Pa, Moreover, as compared with the traditional vacuum concentration, membrane ultrafiltration was easier to obtain high-quality crude ESP with a higher content of polysaccharide, which was helpful for the further extraction and purification of polysaccharides in the following process.The crude ESP which get rid of dissociative protein with sevag reagent was isolated on a ion-exchange column (DEAE- Cellulose 32) to three fractions including ESP-Ⅰ, ESP-Ⅱ,and ESP-Ⅲ. The three fractions were shown to be homogeneous by high performance gel filtration chromatography (HPGFC).ESP-Ⅰ,ESP-Ⅱ,and ESP-Ⅲwere further examined use HPGFC,IC.Results show the molecular weight of ESP-Ⅰ,ESP-Ⅱ,and ESP-Ⅲwere 2.01×104,7.94×103,2.80×105; sulfate content was 1.523%,2.342 %,24.104% ; monosaccharide composition of ESP-Ⅰis D-Xyl : D-Gal : Man =1.00 : 7.18 : 0.51; monosaccharide composition of ESP-Ⅱis D-Xyl : L-Ara : D-Gal : Man =1.00 : 15.05 : 8.10 : 3.05 .