Polysaccharides (polysaccharides) are sugar chains composed of glycosidic bonds, which are polymer sugar carbohydrates composed of at least 10 monosaccharides, and can be represented by the general formula (C₆H₁₀O₅)_n. Polysaccharides composed of the same monosaccharides are called homopolysaccharides, such as starch, cellulose and glycogen. Polysaccharides composed of different monosaccharides are called heteropolysaccharides. For example, gum arabic is composed of pentose and galactose. The polysaccharide is not a pure chemical substance, but a mixture of substances with different degrees of polymerization. Polysaccharides are generally insoluble in water, have no sweet taste, can not form crystals, and have no reducing and turning phenomena. Polysaccharides are also glycosides, so they can be hydrolyzed. During the hydrolysis process, a series of intermediate products are often produced, which are finally hydrolyzed to obtain monosaccharides.

Figure 1. Cellulose.

Applications:

• Immunomodulation: After ultrasonically crushing and extracting the cells of Bifidobacterium spp., polysaccharides with immunoenhancing activity can be purified by ultrafiltration equipment, anion exchange resin and gel chromatography. The polysaccharides isolated from Perilla also have anti-allergic effects. Polysaccharides extracted from the fruiting bodies of mushroom (Agr/cus) plants have an immunosuppressive effect, which can reduce the side effects of commonly used immunosuppressants (such as cytotoxicity, decreased anti-infection ability of the body, and suppression of the proliferation of bone marrow hematopoietic cells). The polysaccharide can be made into a medicine for oral medication or injection, and can also be made into functional food.

Figure 2. The construction of biopolysaccharide-based hydrogel is used in the field of immune engineering.

• Anti-virus and anti-cancer: The antiviral mechanism of most polysaccharides is to inhibit the adsorption of viruses to cells. A large number of water-soluble substances with anti-cancer active ingredients can be isolated from the culture of mushroom (Agr/cus) plants, including acidic polysaccharides, water-soluble neutral polysaccharides and fruit polysaccharides isolated from the fruiting bodies of mushroom plants water-soluble proteoglycan. The polysaccharides and sulfated polysaccharides with anticancer activity isolated from chlorella and spirulina can also inhibit tumor metastasis, and the safety is better than traditional surgical treatment and chemotherapy. From the antioxidant acid polysaccharides extracted from the nuts of the pecan tree and the legume plant aspa athus linearis can not only inhibit the replication of HIV and other reverse transcriptase viruses but also play an immunoregulatory role to a certain extent. To some extent, it can replace traditional antiviral drugs that are expensive and have large side effects.
• Emulsification: Polysaccharides with emulsification can be extracted from the somatic cell walls of Gramineae Festuca plants (such as barley), which can be widely used as emulsifiers in industrial production, and are safe and pollution-free. By cultivating the gene-producing bacteria geneshuus B, a polysaccharide composed of trehalose and mannose can be obtained and isolated. This polysaccharide has good solubility in water and good stability. It can be used as a stabilizer for abrasives and emulsifiers and thickeners.
• Treatment: Salvia miltiorrhiza polysaccharide isolated from Salvia miltiorrhiza can inhibit the secretion of urine protein and relieve the symptoms of liver and kidney diseases. It can be made into oral or intramuscular preparations to reduce adverse reactions caused by long-term use of steroids such as dipyridamole or platelet inhibitors. Polysaccharide preparations containing sulfated fucoidan active ingredients can also reduce the side effects of non-steroidal anti-inflammatory analgesics such as indomethacin and aspirin.

Figure 3. Salvia miltiorrhiza polysaccharide

References:

1. Zhang Quanbin, Xu Zuhong.(1996) "Research progress of kelp polysaccharide sulfate ester chemistry." China Marine Drugs. (4):38-41.
2. Liu Ke, Wang Qilin, Lu Hui, et al. (2002) "Extraction, purification and treatment of kelp sulfated polysaccharides Chemical analysis." Chinese Journal of Biochemical Drugs. 23 (3):114-116.