Recent advances in Bletilla striata polysaccharide research: extraction methodologies, structural elucidation, pharmacological mechanisms, structure–activity relationships, and therapeutic delivery applications

Bletilla striata is a traditional Chinese medicine (TCM) used for hemostasis, detumescence, and tissue regeneration. Its major bioactive component, Bletilla striata polysaccharide (BSP), is a water-soluble heteropolysaccharide composed primarily of mannose and glucose. Various extraction techniques-including hot water, ultrasonic assisted, and microbial fermentation methods-have been developed to isolate BSPs, with extraction parameters significantly influencing its structural features. BSPs exhibit diverse pharmacological activities, such as wound healing, immunomodulation, anti-inflammatory, antioxidant, and gut microbiota regulatory effects. Despite extensive studies, the structure-activity relationships (SARs) and toxicological profile of BSPs remain incompletely understood. Owing to its favorable biodegradability and biocompatibility, BSPs show promise as a nanocarrier for drug delivery. This review summarizes advanced purification and structural characterization techniques, pharmacological mechanisms, potential toxicities, and drug delivery applications of BSPs, providing a translational framework for future research and development.