The Influence of Monosaccharide Composition on the Bioactivity of Medicinal Plant Polysaccharides

Polysaccharides are natural polymers that are widely found in medicinal plants. Structurally, they are complex molecules composed of long chains of monosaccharide units linked by glycosidic bonds. Modern pharmacological research shows that the bioactivity of polysaccharides is closely related to their monosaccharide composition. This review summarises the monosaccharide composition of 210 polysaccharides from 72 medicinal plants. They were classified into 10 types through principal component analysis (glucans; homogalacturonan; galactans; arabinogalactans; mannans; glucomannans; arabinans; xylans; fructans; rhamnogalacturonan-I). The relationship between monosaccharide composition and biological activity was further analysed. The results are as follows: glucans make significant contributions to immunomodulation, antioxidant activity, and gut microbiota regulation; galactans are crucial for antioxidant effects, immunomodulation, and gut microbiota regulation; mannans play a key role in immunomodulation, antitumor activity, and neuroprotection; fructans are vital for gut microbiota regulation, immunomodulation, and antioxidant effects; and pectins exhibit notable immunomodulatory, antioxidant, and hypoglycaemic properties. Consequently, developing polysaccharides from medicinal plant resources based on their monosaccharide composition is expected to speed up the search for polysaccharides with high biological activity and provide a theoretical reference for polysaccharide research.