Studies On The Purification And Structural Characteristics Of Fucoidan Extracted From Kjellmaniella Crassifoliaon Cultured In Dalian

In this study, Kjellmaniella crassifolia cultured in Dalian was as raw material,sudied fromthree main aspects. The findings and conclusions are as follows:The contents of moisture, ash, protein and fat of Kjellmaniella crassifolia cultured in Dalianwere determined as7.63%,6.26%,34.17%and0.67%, respectively. The orthogonal test wasdesigned to optimize the extracting factors. It was found that the optimal conditions were as thefollowing：the solid-liquid ratio was1:17, the ratio of cellulose, pectased and papain was4:1:1,mixed enzymes added620U/g, pH of4.5, temperature of45℃,and time of60minutes. Underthese conditions, fucoidan yield was1.98%, in which the content of polysaccharides and SO42-were63.33%and25.14%separatedly.Fucoidan purified by anion-exchange chromatography on DEAE-Sepharose Fast Flow.Three fractions, F-1, F-2and F-3were obtained and the yields were10.55%，37.72%and21.98%, respectively. The SO42-contents of F-1, F-2and F-3were15.26%，8.37%and27.16%,respectively. The relative molecular weights were estimated to be145KD for f1,258KD for f2,258KD for f3and69KD for f4by Sephacryl S-300gel filtration chromatography.Molecular structural charateristics of the fucoidan fractions were studied by IR spectrum,GC and NMR.The results of IR spectrum indicated that absorption peaks of O-H（3348-3490cm-1）, C-H(2933-2947cm-1) and S=O(1243-1255cm-1) existed in each fraction, whichdemonstrated that all fractions were fucoidans with sulfate substitutes. The IR band of the f2, f3and f4fractions exhibited adsorptions at approximately850cm-1, which indicated the presenceof sulphategroups at positions4. The IR band of the f1fractions exhibited absorption at834cm-1,which indicated that the f1is likely to have the structure of the double sulfur replace. Thefindings of the monosaccharide composition of these fractions by GC chromatography showedthat, the monomers were fucose, galactose, mannose, xylose and glucose. However, thecomposition ratio of monosaccharides in each component are not the same. f1mainly consists ofgalactose and fucose. In f2, f3and f4, fucose is the major constituent. The results of NMR asfollows:1H NMR spectrum revealed that methyl presented at high field(1.3ppm), acetyl signalpeak presented in2.1-2.2ppm.13C NMR spectra of f1-f4were complex.Intense signals wereobserved in the C1region, and the spectra of f1-f4also appeared to have signals in the high-fieldregion of16-18ppm,which are due to fucopyranoside.The f1-f4showed complex signals ofcarbons C2-5in the region of68-84ppm, which indicates the complex structural patterns of themonomer composition and their glycosylation, sulphation.