Study On The Preparation And Bioactivity Of High Purity Fucoidan From Laminaria Japonica

Laminaria japonica,a kind of universal economic seaweed,is an important rawmaterial in the pharmaceutical industry.Fucoidan exctrated from Laminaria japonica is a unique bioactive compound which has great potential in antiviral,antitumor,antihyperlipidemia and other physiological activities.Therefore,fucoidan has attracted increasing attention from all over the world for its outstanding physiological activities.The Laminaria japonica of Quangang Fujian was used as the raw material to extract fucoidan by hot water and further to purified the coarse alga polysaccharide,obtained different high purity seaweed fucoidan components in this article.Besides,the preliminary structure of different fucoidan was analysed.The main research results are as follows:1.The effects of reaction conditions were investigated to improve the efficiency of Dische colorimetry,and verification methodology was investigated.The research results show that the modified Dische colorimetry can greatly shorten color reaction time,and precision,color stability and added standard recovery are in accordance with the relevant regulations.2.After comparing the yield and the content of sulfate of fucoidan preparated by water extraction and acid,water extraction was used to extract fucoidan.The optimum extraction conditions for the preparation of fucoidan was optimizated with single factor experiment and orthogonal experiment which was as follows:extraction time 3.0 h,temperature 70?,solid-liquid ratio 1:30.The degree of extraction rate was 2.15%under the optimum conditions.Then the physicochemical properties of extracted fucoidan were evaluated with the total sugar content was 35.83%,fucose content 16.66%,protein content 4.39%,and sulfate content 16.06%.3.Ethanol precipitation were used to purify the crude fucoidan.DEAE-cellulose52 and Sephadex G-200 were applied to separate the purified fucoidan.After that,five fucoidan named SF2-1,SF3-1,SF4-1,SF5-1 and SF6-1 were got.The molecular weights were estimated to be 108.7 kDa,92.3 kDa,183.5 kDa,137.4 kDa and 106.1kDa,respectively.4.The monosaccharide composition and mole ratios of SF2-1,SF3-1,SF4-1 and SF5-1 were detected by PMP derivation.The study showed that the different fucoidan fractions was mainly composed of D-?+?-mannose,L-?+?-rhamnose,D-?+?-glucose,D-?+?-galactose,D-?-?-xylose and L-?-?-fucose.Infrared spectrum?IR?and nuclear magnetic resonance?NMR?spectrum were applied for studying the structures of the four fucoidan fractions.In the IR spectra,the existence of absorption peaks of O-H(3470 cm^-1),C-H(2935 cm^-1),and S=O(1250 cm^-1)indicated that all fractions were fucoidans with sulfate substitute.In the ¹H NMR spectra,the chemical shift of the anomeric proton signal at?_H 5.0-5.8 ppm suggested the four components all have sulfated fucose residues.The difference in the anomeric proton region demonstrated various sulfated patterns of FucCS.The ¹³C NMR spectra indicated that the carbon skeleton signals of different fucoidan were similar,mainly composed of L-Fuc.5.The effects of inhibiting cancer cells proliferation and lipid accumulation in vitro of fucoidan in Laminaria japonica.The results showed that the four fucoidan had a strong inhibitory effect on HeLa cells after treatment for 48 h and 72 h.And the fucoidan could suppress the lipid accumulation and decreased the levels of intracellular TG in HepG2 cells.In this paper,the preparation and biological activity of fucoidan from Laminaria Japonica were studied,which provided a theoretical basis for the rational exploitation and utilization of Laminaria japonica.