The Bioactive Compounds From Hizikia Fusiformis

In this thesis, the bioactive compounds from Hijikia fusiformis, such as brown algae polyphenols, water-soluble polysaccharide and glycoprotein were studied. The results will be helpful for the application of H. fusiformis.Screening of potential antibacterial activities of total phenolic compounds isolated from a brown alga H. fusiformis was performed using two antibacterial assays. Significant differences were observed both in total phenolic contents and antibacterial activities of extracts from H. fusiformis collected along the coast of East China Sea and South China Sea against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Enterobacter aerogenes and Shewanella sp. Methanol extracts from H. fusiformis collected in Zhoushan and Mazu exhibited the more antibacterial activities against E. coli. Ethanol extract from H. fusiformis collected in Naozhou had higher antibacterial activity against B. subtilis.Water-soluble polysaccharides were isolated from the brown alga H. fusiformis and separated using hydrophobic chromatography on an ME-1resin column. Three major polysaccharide fractions, FG, GM-1and GM-2, were analyzed by high-performance liquid chromatography, Fourier-transform infrared and13C nuclear magnetic resonance spectroscopy. These three fractions showed free radical scavenging activity against hydroxyl radical and1,1-diphenyl-2-picrylhydrazyl radical in vitro. Among these three fractions, GM-2had the best free radical scavenging activity. Thus, only GM-2was used in the acute oxidative stress experiments in the CCl4-induced liver injury model. GM-2also protected against oxidative injury induced by CCl4in vivo.The weight, loading swimming time, the activities of blood SOD, the content of blood MDA, liver glycogen, muscle lactic acid, the content of blood urea nitrogen were measured after15days through being given different doses (50mg/mL·d and150mg/mL·d) of ME-2to mice. The results showed that the loading swim time, the activity of SOD and the concentration of liver glycogen were enhanced while the concentration of MDA, muscle lactic acid, and urea in blood were decreased.The glycoprotein (HFGP-A) was isolated from H. fusiformis by ammonium sulfate precipitation. ion exchange on Cellulose DE52and HPLC. The total carbohydrate content was found to be41%. The sulfate contents of HFGP-A were no determined. SDS-PAGE showed that the HFGP-A had a molecular mass of19kDa. Gel filtration of HEGP-A on TSK-gel G4000PWx1. indicates that it exists oligomer in its native state. For HEGP, glucose, galactose and fucose were the monosaccharide units, accounting for6%,14%and80%. HFGP-A contains high amount of acidic amino acid Asx. According to the principle of β-elimination reaction, the oligosaccharide moiety and peptide moiety of HFGP-A might belong to N-glucosidic linkage. HFGP-A was analyzed by Fourier-transform infrared,1H and13C nuclear magnetic resonance spectroscopy. HFGP-A showed free radical scavenging activity against hydroxyl radical, DPPH radical and ABTS+·radical.In summary, H. fusiformis contains bioactive compunds, such as brown algae polyphenols, water-soluble polysaccharide and glycoprotein. Whiches will be developed health foods or medicine with antibacterial activity, antioxidant activity or hepatoprotective effect.