The Purification Of Polymannuronic Acids And Polyguluronic Acids As Well As The Research On The Activity Of The Oligosaccharides Of Algin Series

With the development of science and technology, the Mannose acid andGuluronic acid in high purity are widely used in pharmaceutical preparations, clinicalmedical and cosmetics, etc. But the highest purity of M and G which are extractedthrough existing extraction method is at about90%. What’s more, most extracted Mand G are oligosaccharide. Many researches cannot proceed because of this. Therefore,the study of the purification method of polymannuronic acids and polyguluronic acidsof high molecular weight and high purity is extremely urgent. The research canprovide new process for the deep processing of algin, so as to promote theinternational competitiveness of the algin industry of our country.The preparation technology of pure polymannuronic acids and polyguluronicacids and the activity of their oligosaccharides in series were studied on the basis ofprevious.1. The selections of the eluent and the elution concentration with Dowex stronganion exchange column were researched. The eluent of linear elution used HAc, NaCl.The result showed that the Mannuronic acid and Guluronic acid could be eluted andseparated well at a HAc concentration of0.5mol·L-1to2.0mol·L-1. They was elutedrespectively at the concentration around of0.995mol·L-1and0.8mol·L-1with theyield rate34.09%and59.06%.2.The molecular weight and purity of prepared polymannuronic acids andpolyguluronic acids sample were determined based on HPLC and NMR techniques.The result showed that MW(PM)=11930.66Da (polymerization degree is about60),MW(PG)=10741.61Da (polymerization degree is about54). The spectrograms of thetwo glycans were both showed a single-peak curve, and the type of the peaks wassymmetric. These showed that the purities of the both were very high. Combining the NMR, the signal peaks of PM and PG in the1H-NMR spectrograms were identicalwith that of literature. Thus, the two isolates from tests were conformed aspolymannuronic acids and polyguluronic acids. Furthermore, their molecules kept theunique structural features in the macromolecules of algin. There was tiny PG existedin PM through the spectrogram. This might be due to the soft of PM.3. The scavenging effect of oligosaccharides of Algin series on hydroxyl freeradical and superoxide anion free radical and the inhibition effect on lipidperoxidation were studied. The prepared polymannuronic acids and polyguluronicacids in macromolecule were dissolved, and degraded subsequently by adjusting pHunder high temperature. The degradation products was subdivided into fourcomponents (MW<1000,1000<MW<3000,3000<MW<5000and MW>5000)according to their molecular weight by using the ultrafiltration device in order toresearch their antioxidant activities. The result showed that the oligosaccharides ofAlgin series had strong scavenging effect on the two free radicals. Moreover, thescavenging effect was gradually enhanced along with the increased concentration ofthe oligosaccharide according to the test concentration, The higher molecular weightwas the lower ability to scavenge free radicals. The M and G in the same molecularweight had approximately same ability to scavenge the two free radicals. During theinhibition test of lipid peroxidation, the oligosaccharides of Algin series at aconcentration ranging from0to0.2mg/mL could effectively inhibit the lipidperoxidation, and the inhibiting ability was positively related with their respectiveconcentration. However, the inhibiting ability was gradually strengthened with theincreasing molecular weight, so the result was opposite to that of the free radicalsscavenging test.