A review of natural plant polysaccharides: the relationship between extraction methods, physicochemical properties, structures, and biological activity

OBJECTIVES: The pharmacological activities of plant polysaccharides are closely associated with their unique and complex chemical structures. Extraction, as the initial and critical step in polysaccharide preparation, largely determines the yield and quality of the final products. Nevertheless, polysaccharides obtained by different extraction methods often exhibit significant differences in physicochemical properties, structural characteristics and biological activities. Such inherent heterogeneity greatly impedes research on the extraction-structure-bioactivity relationship of polysaccharides. This review aims to elaborate the effects of various extraction methods on the physicochemical properties, structures and biological activities of plant polysaccharides, so as to provide a theoretical basis for the development and utilization of polysaccharides. METHODS: Recent published studies focusing on plant polysaccharide extraction, structural identification and biological functions were collated and narratively integrated to analyze the internal relevance between extraction approaches, structural characteristics and bioactivity. KEY FINDINGS: Extraction methods can directly alter the core structural characteristics of plant polysaccharides, including monosaccharide composition, molecular weight, sugar chain conformation and microstructure. These structural differences further regulate the pharmacological activities of polysaccharides, such as antioxidant, antiviral, antitumour, anti-inflammatory and immunomodulatory effects. CONCLUSIONS: This paper clarifies the relationships between extraction methods and the physicochemical properties, composition, structure as well as biological activities of polysaccharides. The findings facilitate rational selection of polysaccharide extraction approaches, improvement of extraction efficiency, and fuller utilization of plant polysaccharide resources.