International Journal of Molecular Medical Science, 2025, Vol.15, No.2, 89-97 http://medscipublisher.com/index.php/ijmms 90 care and medical treatment. It is hoped to provide reference for researchers and industry professionals and support the utilization of Cordyceps sinensis polysaccharides in the development of drugs and health products. 2 Structural characterization of Cordyceps polysaccharides 2.1 Chemical Components of Cordyceps polysaccharides Cordyceps sinensis polysaccharides are mainly composed of monosaccharides such as glucose, galactose and mannose. For example, the neutral polysaccharide SDQCP-1 in Cordyceps militaris is composed of mannose, glucose and galactose in a molar ratio of 13.3: 1.0: 9.7 (Zhang et al., 2020). Another polysaccharide, CMP-III, was obtained from Junjiao Grass and was composed of glucose, mannose and galactose in a ratio of 8.09:1.00:0.25 (He et al., 2019). These data demonstrate the coexistence of the same monosaccharides in different polysaccharides. In addition to monosaccharides, Cordyceps sinensis polysaccharides sometimes also contain proteins or polypeptides. For example, Cordyceps militaris polysaccharides extracted from subcritical water do not contain protein, indicating that the extraction method can affect the presence of protein (Luo et al., 2017). Different purification processes can lead to variations in the contents of proteins and polypeptides in polysaccharides. 2.2 Molecular weight and structural diversity The molecular weight range of Cordyceps sinensis polysaccharides is relatively wide and is affected by the extraction and purification conditions. For example, the average molecular weight of CMP-III reaches 4.796×104 kDa (He et al., 2019). Another research report indicates that the molecular weights of CMP-W1 and CMP-S1 are 3.66×105 Da and 4.60×105 Da respectively, suggesting a significant difference in molecular weights (Luo et al., 2017). The molecular weight of polysaccharides has a significant influence on biological activity. For instance, high-molecular-weight CMP-III can significantly enhance phagocytosis and cytokine secretion in macrophages, indicating that its molecular weight is related to immunomodulatory ability (He et al., 2019). Polysaccharides with specific structures such as CMPB90-1 can promote lymphocyte proliferation and enhance NK cell toxicity, further demonstrating the importance of molecular weight and branch structure to function (Bi et al., 2018). 2.3 Glycosidic bond types and chain structures Cordyceps sinensis polysaccharides contain a variety of glycosidic bonds, which increase their structural diversity and activity. Common key types include 1→3, 1→4 and 1→6 keys (Wu et al., 2005; Guan et al., 2011; Wu et al., 2014). For example, the main chain of CMPB90-1 is alternately composed of (1→6)-and (1→3)-α-D-glucose residues, and has branches at the O-6 position (Bi et al., 2018). The main chains of another polysaccharide are (1→2) -α -D-mannose and (1→4) -β -D-glucose structures, and the side chains fork at O-6 (Zhang et al., 2020). The existence of these bonds is crucial to the stability and function of polysaccharides. By comparing linear and branched-chain polysaccharides, it can be known that branched-chain structures usually have stronger activity. For example, the branches of CMP-III contain 1→4,6)-α -D-mannose and 1→2,6)-α -D-galactose bonds, which are associated with their significant immunomodulatory efficacy (He et al., 2019). Linear polysaccharides containing only the (1→3)-α-D-glucose main chain have a relatively simple structure but still maintain certain biological functions (Wang et al., 2011). 2.4 Structural analysis techniques The sugar composition of Cordyceps sinensis polysaccharides is commonly determined by high performance liquid chromatography (HPLC) and gas chromatography (GC). For example, HPLC and GC have been used to determine the proportions of glucose, mannose and galactose in various Cordyceps polysaccharides (He et al., 2019; Zhang et al., 2020). Nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR) are key tools for resolving bond forms and functional groups. NMR can identify the bond types of 1→2, 1→4 and 1→6 in polysaccharides (Liu et al., 2016; He et al., 2019), while FTIR can confirm the pyranose conformation and specific functional groups (Luo et al., 2017).
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