Research advance in the preparation techniques, structural characteristics, bioactivities and potential applications of Cassia obtusifolia polysaccharides: A systematic review

Cassia obtusifolia polysaccharides (COPs) have attracted considerable attention for their antioxidant, immunomodulatory, anti-fatigue and eye-disease-treating activities, showing promise in medicine and functional foods. However, current research on COPs is hindered by inefficient extraction, unclear structure-activity relationships and ambiguous biological mechanisms. This review comprehensively summarizes the recent advances in extraction techniques, highlighting that combined extraction methods, such as microwave- or enzyme- assisted extraction can effectively enhance yields while preserve the structure of COPs. Mannose and galactose dominate monosaccharide composition of COPs, with mannose (43.0 %–80.3 %) crucial for the structure of COPs. The molecular weight of COPs (24.3 kDa–70.4 kDa) is affected by extraction methods and impacts bioactivities. Separation methods like deproteinization and chromatography are essential to obtain the pure COPs. Furthermore, COPs have diverse biological activities related to their structural features, and a detailed quality evaluation system for COPs is presented. COPs also have potential applications in drug delivery, nutraceuticals and food packaging. In conclusion, optimizing extraction, clarifying structure-function relationships and conducting comprehensive research are vital to fully utilize COPs' therapeutic potential. The review's novelty lies in its comprehensive compilation, the in-depth analysis of combined extraction, the systematic study of structure-activity relationships, and the detailed discussion on quality evaluation and applications.