The ocean is rich in biological resources, and the types of Marine organisms account for about 87% of the earth's biological total. These organisms live in a buffer system with certain water pressure, high salinity, small temperature difference, limited dissolved oxygen, and limited light. Due to the special living environment, the synthesis process of polysaccharides in Marine organisms is different from that of terrestrial organisms, and many active substances with novel structures and special functions are produced.

Polysaccharide is one of the major Marine biological active substances, polysaccharides isolated from various Marine organisms, from the source can be divided into Marine animal polysaccharide, Marine plant polysaccharide and Marine microbial polysaccharide.

Marine polysaccharides have proved to have many biological activities and medicinal functions such as anti-tumor, anti-viral, anti-cardiovascular disease, anti-oxidation, immune regulation, etc." Anti-tumor Marine drug research has been playing a leading role in this field of research, and at least 10% of Marine biological extracts have been found to have anti-tumor activity, and 3.5% of compounds obtained from Marine plants have anti-tumor or cytotoxic activity." The antitumor activity of Marine polysaccharides has been paid more and more attention. This article reviews the research progress of Marine polysaccharides in the treatment of tumor diseases.

Classification

Algal polysaccharide

Algal polysaccharide refers to various macromolecular carbohydrates contained in seaweed, including alginic acid, algal starch, algin gum, agargel and carrageenan.

Marine animal polysaccharide

Marine animal polysaccharides include chitosan, fish, shellfish, stichopus japonicus, sea urchin and other organisms contain polysaccharides and acid mucopolysaccharides

Marine microbial polysaccharide

Marine microbial polysaccharides mainly refer to microbial extracellular polysaccharides, which are mostly isolated from bacteria in Marine mud, seawater and seaweed.

Antitumor activity of various Marine polysaccharides

1.1 Antitumor activity of Marine plant polysaccharides

Wang Hui et al. studied the anti-proliferation activity of the water extracts of 12 kinds of seaweed in Hong Kong waters against HL-60 and MCF-7 cell lines. 8 kinds of seaweed extracts inhibited the proliferation of HL-60 cells, and 10 kinds of extracts inhibited the proliferation of MCF-7 cells. Among them, Hydroclathrus clathratus has a good anti-tumor cell proliferation effect, and some

Polysaccharide components extracted from this algae can inhibit the proliferation of HL-60 and MCF-7. The polysaccharide component H3-a, which was extracted from reticulum pancreatic algae, could significantly inhibit the proliferation of ascites sarcoma S180. Fucoidan has strong biological activity, not only has immunopromotion and antiviral effect, but also has anti-tumor activity. Sargassum henslowa-num sulphate polysaccharide had obvious inhibitory effect on Eiderian ascites tumor and ascites sarcoma S180 in mice. SargA, a polysaccharide component extracted from Sargassum stenophyllum, has anti-angiogenic activity and cytotoxic activity of anticancer cells. Sargassum thunbergu polysaccharide has anti-cancer, anti-insect, anti-virus and anti-ulcer effects.

Two high sulfated low molecular weight polysaccharide components SP-3-1 and SP-3-2 were extracted from Caraway wormwood by means of supercritical extraction, ultrasonic extraction, membrane filtration and ion exchange. These two polysaccharide components have good inhibitory activity against HepG2 cells, A549 cells and MGC-803 cells. Polysaccharide Cf-PS extracted from seaweed Capsosiphon fulvescens with hot water inhibited the growth of AGS cells dose-dependent, significantly increased the activity of caspase-3, decreased the expression of Bcl-2, and induced cell apoptosis. Experiments showed that the polysaccharide induced apoptosis of tumor cells by inhibiting IGF-IR-mediated PI3K/Akt pathway. CPPS la and CPPS Ila, two polysaccharide components isolated from Chloreoceras proteinosa, showed good inhibitory activity against the proliferation of human lung adenocarcinoma cell A in vitro. Among them, CPPS Ia activity was better, and the inhibition rate of A549 at 1mg/ml concentration was 68.7%, which was similar to the positive control 5-fluorouracil (68.5%).

1.2 Antitumor activity of Marine animal polysaccharides

Chitin , namely chitin, chitin, is a kind of natural polymer from Marine invertebrates, fungi, insects, belonging to aminoglycan, the scientific name is β-(1,4) -2-acetamido-d-glucose. Chitin has good antitumor activity, especially chitosan. In 1985,Suzuki et al. used chitosan to conduct anti-tumor tests on mice, and the results showed that the polysaccharide could stimulate the immune system and induce the production of anti-tumor cytokines. The mechanism of action was as follows: N-acetyl-D-glycosamine (GlcNAc) or D-glycosamine (GlcN) residues bound to the surface receptors of macrophages and activated macrophages to release IL-1 At the same time, it causes the expression of IL-2 receptor on the surface of T cells, which in turn accelerates the differentiation and maturation of T cells into cytotoxic T cells, thus producing anti-tumor effects. In addition, the surface of chitosan has more positive charges, which can neutralize the negative charges on the surface of cancer cells, and has the effect of directly inhibiting tumor cells.

Shark bone contains chondroitin is a kind of sulfuric acid polysaccharide, in the head shark and basking shark contain this cartilage component, after processing to extract to galactosamine and Pro, Gly based peptide glucan, animal experiments have proved that the component can inhibit the growth of blood vessels around the tumor, the tumor cells lack of nutrition and atrophy. Liu Chunhui et al. extracted a water-soluble polysaccharide component SEP from the eggs of Strongylocentrotus nudus of Dalian, which could significantly inhibit the growth of ascites sarcoma S180. SEP can also stimulate the proliferation of splenic lymphocytes in mice with S sarcoma, suggesting that the antitumor effect of the polysaccharide may be related to its immunomodulatory effect. Two water-soluble polysaccharides PEF1 and PEF2 were extracted from Ruditapes philippinarum with molecular weights of 2.0x106 and 5.0x103, respectively. The two polysaccharide components have good inhibitory activity on SMMC-7721, and the activity of PEFI is better than that of PEF2. PEFI and PEF2 also inhibited the proliferation of ascites sarcoma S180 in a dose-dependent manner.

1.3 Antitumor activity of Marine microbial polysaccharides

"Flawbacte-rium ugliginorinactan MP-55, a neutral heteropolysaccharide marinactan consisting mainly of glucose, mannose and alginosaccharide, flawbacte-rium ugliginorinactan MP-55, Flawbacte-rium ugliginorinactan MP-55, inhibits the growth of ascites sarcoma S cells". The daily injection of Marinactan10~50mg/kg to mice inhibited the growth of solid tumor S180 after 10d, with a tumor inhibition rate of 70%-90%. Pseudom onasSP.WAK21 strain cultured by Masahiro and others showed cytotoxicity against human tumor cells with an average median inhibitory concentration of 63.2 μg/ml against 39 cell lines. They were particularly sensitive to CNS and lung tumor cell lines. Liang Jingjuan et al. screened a strain of Bacillus pumilus PLM4 from mangrove Marine stasis in Beibu Gulf of Guangxi. The fermentation broth of the bacterium had inhibitory activity on the growth of human throat cancer cells Hep22, liver cancer cells BEL27404 and tongue cancer cells TCA8123. The polysaccharide was purified by ethanol precipitation and gel column chromatography with antitumor activity. Polysaccharide YCP obtained from Marine fungus YC(Keissleriellasp.YC4108, code :YC) can significantly improve the immune function of tumour-bearing mice, and significantly inhibit the growth of Lewis lung cancer transplanted tumors in mice.

The diversity of Marine organisms determines the diversity of Marine polysaccharides. Polysaccharides with anti-tumor activity have been isolated from Marine plants, animals and microorganisms. Due to the different structure of polysaccharides, the anti-tumor mechanism is also different: some polysaccharides produce anti-tumor activity by enhancing the immune activity of the body; Some polysaccharides have cytotoxic activity directly or induce apoptosis of tumor cells. Some polysaccharides inhibited the activity of topoisomerase in tumor cells. Some polysaccharides inhibit angiogenesis. With the deepening of research, it is believed that more polysaccharides with anti-tumor activity will be discovered and utilized.