| Cancer is a serious disease directly threatening human health and lives. Currently it hasa tendency of global prevalence.Compared with chemical drugs, natrual anticancer activesubstences have become the main choice of the anticancer drug screening with theadvantages of broad–spectrum, high-performance and low toxicity and less sideeffect.Bioactive polyose have become the focus of attention of medical workers and foodscientists due to its multiple biological activities. The sea is the origin of life and has aspecial environment such as high salt, high pressure, low temperature and lack of light.TheMarine biological polysaccharides are different from the terrestrial organisms and itsantitumor activity is especially noticed.Scallop is one of the important marine resources allover the world. It has high nutrition value and contains many physiologically-activecomponents. In this paper, the antitumor active polysaccharides were extracted andpurified from the Bay Scallop, its anticancer activity and mechanism of its toxicity werealso studied.which will lay the foundations for its further reseach and deep development.The main results are as following.(1) Polysaccharides were isolated from bay scallop by hot water extraction technology.This extraction process was optimized by single factor experiment method and responsesurface methodology (RSM). The optimum conditions were determined as follows:extraction temperature90℃, liquid-solid ratio50.0mL/g and extraction time180min.Under those conditions, the average extraction rate of bay scallop polysaccharides was57.7mg/g.(2) The protein removal methods from bay scallop polysaccharides were also explored,the result showed that75%alcohol precipitation combined with TCA method couldeffectively remove the protein in polysaccharides with the rate of removal up to91.80%.Further isolation was carried out using DEAE-52cellulose ion exchange chromatography,neutral and acidic polysaccharides were obtained finally, the acid polysaccharides was itsmain ingredient, but details of the acidic polysaccharides composition and its structureneed further study.(3) The antitumor efficiency and mechanism of bay scallop polysaccharide showed that the polysaccharide had direct cytotoxic effects on tumor cells cultured in vitro, whichcould suppress the growth of marine melanoma cell line B16F10, human epithelial ovariancancer cell line SKOV3and human hepatocellular carcinoma cell line HepG2. Aftertreated with bay scallop polysaccharide of20.0mg/mL, the morphology, microstructureand ultrastructure of these tumor cells were changed, characterized by cell shrinkage,transparency decrease, membrane structure change, nuclear structure change and nuclearchromatin pyknosis etc, and the cell cycle was blocked in varying degrees.(4) By establishing the model of hepatoma cell line H22ascitic tumor bearing mice,the antitumor effect in vivo of different doses of bay scallop polysaccharide given byintragastric administration was studied. The results showed that the appropriate dose of bayscallop polysaccharide could inhibit the appearance of mouse hepatoma cell line H22ascitictumor and prolong the survival time of the mice.(5) The research on the immune enhancing activity of bay scallop polysaccharideshowed that bay scallop polysaccharide had no significant effects on mice liver index, butcould obviously improve spleen index, thymus index, phagocytic index and phagocyticrate of peritoneal macrophages and Spleen T-lymphocyte transformation ability. It hadstrong immune enhancing activity and high safety.(6) The antioxidative activity of bay scallop polysaccharide was studied. Bay scalloppolysacchrides had showed strong antioxidant activity in vitro and could remove hydroxylradicals, DPPH and superoxide anion radicals in the experimental system and had strongreducing capacity. The results showed that the appropriate dose of bay scalloppolysaccharide could improve the activity of SOD, GSH-PX and CAT in mice liver andkidney tissues in vivo, decrease the content of MDA and increase the body’s antioxidantcapacity. |
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