Determination And Preparation Of L-fucose From Laminaria Japonica

Laminaria japonica Aresch, mainly cultured in the coastline, is one of theimportant economic seaweed in brown seaweeds. In the past years, L-fucose haveacquired special significance as a constitutent of the common brown seaweed . Itspreparation from Laminaria japonica will increase the high economic merit of ouralgal industry and advance the further development of algal culture industry. L-fucose (also named 6-Deoxy-L-galactose) is a rare monosaccharide that isoccurring in the L-configuration naturally. It is almost present in the all brownseaweed but to a differ in the content . A peculiar characteristic of L-fucose is itspresence in organisms at the non-reducing terminal position.In kelp,its presence is inthe form of fucoidan. Fucoidans present in brown seaweeds are usually very complexnonregular polysaccharides, which may be even mixtures of molecules of differentstructural types.Its component is different for a variety of seaweeds. but it is mainlycomposed of L-fucose-4-sulfate. Previous reports and experiments showed that L-fucose as well as some othermonosaccharides exhibit interesting biological properties. For example, it has beendemonstrated that L-fucose and L-fucose containing oligosaccharides have potentialapplication in the medical field in preventing tumour cell colonization of the lung(anticancer effect), in controlling the formation of white blood cells(anti-inflammatory effect), in the treatment of rheumatoid arthritis, in the synthesis ofantigens for antibody production(rational immunization) et al. Moreover, L-fucose isan important biochemistry reagent. For all these reasons on the pharmacological properties of L-fucose , it is crucial 3for us to devise a simple and efficient method for preparation of L-fucose, anddetermine the content of L-fucose by advanced test means. and to ensure its biologicalactivity and the application in the medical fields have an important theoreticsignificance and applied value. In this study, we determined the content of L-fucose in fucoidans fromLaminaria japonica and established the optimum producing technological conditionof L-fucose from Laminaria japonica through lots of experiments. The preparation ofL-fucose has the following flow chart:kelp powder distill polysaccharide enrichment acid degradation L-fucose In the present paper, we described Dische colorimetry and GC methods for thedetermination of L-fucose content in fucoidans. Colorimetry indicated that the contentof L-fucose in the selected fucoidan samples was 29.08％,26.31％,25.62％,28.59％,respectively, with the coefficient of variaton from 0.98‰ to 1.75‰. GC analytical method indicated that the content of L-fucose in the selectedfucoidan samples was 32.9072％,32.3147％,32.2924％,32.3571％,respectively. Therecovery ranges from 97.1％ to 99.9％ with the coefficient of variaton from 0.23‰to 0.60‰. Though a series of experiments and on the basis of ultimate yield ,monomercontent,optical rotation,chromaticity, crystal and so on , we obtained optiumtechnology conditions. Meanwhile, we investigation the inflence of de-salt andde-colorization craft on the product quality.By IR , H-NMR and 1 13C-NMR,ourexperimental products are consistent with that of Sigma corp. This work establish anexcellently technological guarantee for the future industrializaton. In conclusion, this study is a strongly supplement for the high annexable productof algal industry. It has an important significance for the comprehensive utilization ofLaminaria japonica .