Polysaccharides are one of the four essential biomolecules for life and exhibit diverse biological activities and functional properties. The development and application of polysaccharides depend on the discovery of high-quality polysaccharides, the elucidation of their fine structures, and the advancement of their synthesis and preparation technologies. However, conventional extraction and research methods are plagued by high energy consumption, environmental pollution, and low efficiency. Polysaccharide green manufacturing technologies are designed to obtain, modify, and produce functional polysaccharides through environmentally friendly and sustainable approaches. Current research progress mainly involves three aspects: green extraction, green modification, and synthetic biology. Green extraction technologies achieve low energy consumption and high efficiency while maximally preserving the native structure of polysaccharides. On this basis, green modification technologies enable targeted structural modification, thereby improving the physicochemical properties and biological activities of polysaccharides. In addition, synthetic biology provides new strategies for the de novo design and controllable synthesis of polysaccharides with specific structures and functions. This review summarizes recent advances in the green extraction, green modification, and synthetic biology of polysaccharides, aiming to provide theoretical support and technical references for the sustainable development and high-value utilization of polysaccharide resources.

A polysaccharide is a macromolecular polymer composed of more than 10 monosaccharide molecules through condensation and dehydration, and it is an essential substance for life. However, most plant polysaccharides cannot be digested by enzymes encoded by the human genome. The intestinal flora consists of a variety of microorganisms that reside in the gastrointestinal tract of the host, including Bacteroidetes and Firmicutes as well as lesser quantities of Actinobacteria and Protebacteria, which can secrete polysaccharide-degrading enzymes to promote the digestion and absorption of polysaccharides. Non-digestible polysaccharides and short-chain fatty acids (SCFAs) in the fermentation products can further regulate the composition of the intestinal flora, improve intestinal function, and participate in regulating the expression of anti-pathogenic microorganism, anti-inflammatory, anti-tumor genes, thereby treating diseases and maintaining health. This article summarizes recent progress in understanding the interaction between polysaccharides and the intestinal flora, which will provide a scientific basis for further studies on human health and rational diets.

Codonopsis Radix, the dried roots of the genus Codonopsis of Platycodonaceae, has a very long history of culinary and medicinal use in China and is considered to strengthen the middle warmer and benefit vital energy as well as to benefit the stomach and help produce saliva in Chinese medicine. Codonopsis Radix contains a rich variety of chemical constituents, including flavonoids, alkaloids, polysaccharides, saponins, steroids, trace elements and amino acids, with many pharmacological effects, such as enhancing immunity, protecting the heart, nerve and gastrointestinal tract, regulating blood sugar, antioxidant, anti-fatigue, antibacterial, anti-virus, and anti-tumor functions, so it has been increasingly applied as both food and medicine. In this article, the chemical composition, pharmacological actions and application of Codonopsis Radix are reviewed so as to provide a reference for understanding the theoretical basis for the health benefits of Codonopsis Radix as well as for its development and application.

Polysaccharides are a class of natural macromolecular polymers with complex and large molecular structures, which are closely related to their biological activities. However, traditional analytical methods can only provide limited information on the structures of polysaccharides. Mass spectrometry (MS) is an analytical method that measures the mass-tocharge ratio of molecules allowing for determination of the mass and calculation of the the molecular structure. As a powerful tool for polysaccharide structure analysis, MS can provide rich information, including molecular mass, polymerization degree, monosaccharide composition, glycosidic bond type, the order of arrangement of glycosyl groups, and substituent group sites, which has unique advantages in the characterization of polysaccharide structure. This paper summarizes the general pattern of mass spectral fragmentation of polysaccharides, introduces the principles and characteristics of different types of MS as well as representative applications of MS combined with electron ionization source, fast atom bombardment source, electrospray ionization source, matrix-assisted laser desorption ion source, real-time direct analysis source, ion mobility or tandem mass spectrometry for the structural elucidation of polysaccharides. Furthermore, future prospects for the application of new MS techniques for analyzing the structures of polysaccharides are discussed. The aim of this paper is to summarize the application of MS to provide scientific reference for the basic research work of polysaccharide compounds, such as quality standard, structural characterization, pharmacodynamics, pharmacokinetic, constitutive relationship, and the development and creation of polysaccharide food, health food, and clinical drugs.