Study On The Activity And Absorption Characterisitic Of Sea Cucumber Fucoidan And Its Partially Degradation Products

Sea cucumber is a traditional costful tonic sea food in China,which contains multi-kinds of bioactive components. It is well known that holothurians are of high nutrition and pharmic values. Sulfated polysaccharide, one of the most important bioactive compositions of sea cucumbers, is including Sea Cucumber Chondroitin Sufate (SC-CHS) and Sea Cucumber Fucoidan (SC-FUC). High molecular mass and viscous nature of fucoidan may hamper its use. Therefore, knowledge of the absorptive characteristics of exogenous fucoidans after oral administration is very important in the view of promoting the whole level of sea cucumber processing industry. On this background, low-price sea cucumber was chosen as material, and sea cucumber fucoidan was employed as the subject of this research. The main researches in this thesis are listed below:1. Preparation of SC-FUC with different molecular mass. Sea cucumber polysaccharide was extracted, and SC-FUC was furthermore purified. Yield, protein content, molecular mass and sugar composition were determined by different methods. The conditions of fucoidan degradation by H2O2, H2SO4 and enzyme were studied. The results showed that the reaction rate of H2O2 degradation was too violent to control, the reaction rate of H2SO4 degradation can be regulated and have a poor reproducibility and lower SO4-2 retention rate, the reaction rate of enzymatic degradation was mild and good reproducibility but complex operation. The sample prepared by acid degradation was 50.0kD, sulfate content of 16.56%. The sample prepared by enzymatic degradation was 437.8 kD,52.7 kD and 20.5 kD, sulfate content of 22.3%,21.4% and 21.7%.2. In order to observe the effects of SC-FUC with different molecular mass on fatty liver, orotic acid fatty liver model was used. The results showed that various SC-FUC did not affect the growth of rats and could significantly reduce the hepatic TC levels (P <0.01), seaweeds fucoidan and low molecular weight sea cucumber fucoidan could significantly reduce the hepatic TG levels (P <0.05). The results indicated that fatty liver regulation activity of SC-FUC was related to its molecular mass and SC-FUC with lower molecular mass had a better effect.3. The determination for fucose content from rat serum. A high performance liquid chromatography with precolumn derivatization (PMP-HPLC) has been developed and compared with the cysteine-phenol-sulfuric method (CPS) for the determination of the levels of fucose in rat serum. The hexoses and fucose could be determined at the same time by the CPS. The fucose recovery was 126.22% and RSD was 5.31%. Compared with CPS, the PMP-HPLC method was more sensitive, accurate, reproducible and suitable for analysis of serum. The recovery is 103.42% for fucose and RSD was 3.34%.4. Oral absorption and bioavailability of SC-FUC and its partially depolymerized products in rats. We characterize the absorptive course of SC-FUC and its partially depolymerized products in rats by PMP-HPLC. The results showed that fucoidan with a high molecular mass and charge density could be absorbed and the polymer cross the gut wall at a rate varying inversely with polymer size.5. Correlation between hepatic lipid concentrations and serum monosaccharide contents in fatty liver. The changes of serum monosaccharide composition were found in fatty liver rat induced by orotic acid and showed a significant correlation to hepatic lipid concentrations. But the serum monosaccharide composition of the acute model induced by CCl4 showed unchanged. Basis of this, the monosaccharide composition of fatty liver cases was studied. The results indicated that glycometabolism may play an important role in the pathogenesis and progression of fatty liver diseases. It suggested that the change of serum monosaccharide composition may be used as a new marker in addition to other markers for fatty livers.Above all, partially depolymerized products of SC-FUC not only improved the absorption characteristics,but also promoted the regulation of fatty liver. Those results provide a theoretical base for low molecular SC-FUC application, and will contribute to development of sea cucumber fine processing and price increment.