Investigation Of Chemical Composition And Biological Activities Of Polysaccharides From Enteromorpha

A large-scale green tide occurred in the Yellow Sea just before the 29th Olympic Games. The green tide algae was classified as Enteromorpha prolifera. Enteromorpha is a common green algae distributing in Qingdao coast. This work determined chemical composition of two samples, which are growing naturally (QE) and the green tide algae (GE) in Qingdao coast, and investigated the properties of the polysaccharides from them.Chemical analysis indicated that the content of moisture, carbohydrate, ether extract and protein are higher in GE, but QE had a larger amount of ash than its counterpart. Among the founded amino acids, Glutamic and Aspartic acid were present in the highest quantity. Essential amino acids accounted for 42.755% and 44.989% of total amino acids. Unsaturated fatty acids represented 34.156% and 34.278%, respectively. Enteromorpha was recommended for human consumption because it has several beneficial components, such as minerals, protein, essential amino acids, and essential fatty acid.Polysaccharides from QE and GE were named QEP and GEP, respectively. The isolation and purification of the polysaccharides were performed on a DEAE-Sepharose FF anion-exchange column. Neutral sugars were analyzed by HPLC. Rhamnose represented 67.55% and 65.56%; Xlyose account for 24.61% and 19.33% of total neutral sugars. Anion-exchange chromatography indicated that, QEP had two sub-fractions, glucuronoxylorhamnan and glucuronoxylogalactorhamnan; and GEP had one main glucuronoxylomannorhamnan fraction. Structure features of QEP were analyzed by FTIR, methylation analysis and NMR. A computational method by ChemNMR had been proposed for assistance in the assignment of the structure. The polysaccharides were branched and contained (1→4)- and (1→2,4)-linked rhamnopyranosyl, (1→4)- xylopyranosyl. Sulfate groups were located at C-3 of rhamnose units.The in vitro scavenging activities on superoxide radical, hydroxyl radical and DPPH, and reduction power of QEP and sub-fractions were investigated. All fractions showed certain antioxidant activities, especially QEP. The properties of moisture absorption and moisture retention of GEP and FPS samples were investigated by controlling the relative humidity and compared with glycerol and hyaluronic acid. GEP, low molecular FPS and acetylated low molecular FPS had similar properties with HA. It is concluded that polysaccharides from Enteromorpha linza can be developed as natural moisturizer, because of its richness of raw material, easy preparation and strong activities.