| The marine shellfish resources are abundant in China, and the polysaccharides are important bioactivity substances in shellfish. Due to the special marine environment, the shellfish polysaccharides possess unique and complex structure and have a good application prospect in antitumor, antiviral and improving immune function and so on. Research on shellfish polysaccharides has attracted wide attention of scholars both at home and abroad. Sinonovacula constricta and Solen gracilis belong to solenidae, bivalvia, Mollusca. Not only they contain protein, sugar, calcium, iron and vitamins, which have high value of nutrition; but also they have potential pharmaceutical value, possessing the activities of heat-clearing and detoxifying, anti-inflammation, dysentery treating, lactogenesis and so on. In this paper, the crude polysaccharides were extracted by different methods from both Sinonovacula constricta and Solen gracilis, which were obtained from Qingdao coastal area, and were purified by different methods. The physicochemical property and structure of polysaccharides were analyzed. The activities of polysaccharides on anti-HBV and immune were also studied. The results are as follows:1. Sinonovacula constricta polysaccharides were extracted by distilled water at 100 ℃ and alkali solution sequentially, with the yield of 7.20% and 8.90%. The total sugar content of YC-S and YC-J were 55.4% and 38.1%. The protein content of YC-S and YC-J were 29.5% and 25.8%. The monosaccharide composition of YC-S and YC-J consist of only Glc, and four polysaccharides (YC-S1, YC-S2, YC-J2 and YC-J2) were isolated by Q sepharose fast flow anion-exchange chromatography. YC-S2 was further puried by Sepharcryl S-300 gel-permeation chromatography. Its content of total suger and protein were 90.9% and 8.7%. The relative molecular weight of YC-S2 determined by high performance liquid chromatography is 482 kDa. The structure of YC-S2 was determined to be a-(1→4)-D-glucopyranose, with a little β-(1→3,4) and β-(1→4) branched units characterized by IR. methylation method, GC/MS and NMR.2. Solen gracilis polysaccharides were extracted by distilled water at 100 ℃ and alkali solution sequentially, with the yield of 12.9% and 3.5%. Eight polysaccharides were isolated by Q sepharose fast flow anion-exchange chromatography. The total sugar content and protein content of ZC-S were 14.2% and 59.3%. The total sugar content and protein content of ZC-J were 12.6% and 76.3%. The monosaccharide composition of ZC-S and ZC-J was complex. The molar ratio of ZC-S is Glc:GIcN: Gal:GalN:Fuc:Man=16.1:2.9:2.1:1.9:1.7:1. The molar ratio of ZC-J is Glc: GlcN:Gal:Man:GlcN:Fuc=9.1:2.1:1.5:1.1:1.1:1. The structure of the side chains and the main chains was analyzed by a multistage acid hydrolysis strategy. Under the action of TFA with low concentration, the side chains of ZC-S and ZC-J were compsed of Fuc, Gal A and Rha. The main chains of ZC-S and ZC-J were analyzed by a methylation method and GC/MS. The main chains of ZC-S and ZC-J mainly contained three kinds of linkage type units: →4)Glc(l→, →3,4)Man(1→ and →4,6)Gal(1→. In addition,→2,4)Glc(1→ was also found in ZC-S.3. Solen gracilis polysaccharides possessed good immune activity. ZC-S2, ZC-S3-ZC-S4 and ZC-J2-ZC-J4 could significantly promote the immunologic function of mice at concentration of 50 μg/mL,100 μg/mL and 200 μg/mL, respectively. However, YC-S2 only showed a weaker effect on immunological enhancement. ZC-S2 and ZC-S3 had affinity to HBeAg and HBsAg at a concentration of 200 μg/mL, and their inhibition rates were about 38% and 35%, respectively.The recent studies on Sinonovacula constricta and Solen gracilis polysaccharides were mainly focused on the extractionand pharmacological activity, however, there are little reports on the purification, structure, immunostimulatory activity and anti-HBV activity. Our results not only provide basis for further research on the biology activity and structure about Sinonovacula constricta and Solen gracilis polysaccharides, but also provide references on the high-value utilization of marine shellfish resources, such as Sinonovacula constricta and Solen gracilis. |
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