Extraction, purification, structural characterization, and biological activity of polysaccharides from Dendrobium...

Dendrobium huoshanense C. Z. Tang & S. J. Cheng is a perennial herb belonging to the genus Dendrobium in the Orchidaceae family. Its stem is used for medicinal purposes. The species has a long history of both edible and medicinal use and is recognized as a Chinese geographical indication product. The D. huoshanense polysaccharides (DHPs) are the main active components of D. huoshanense, and are primarily composed of glucose, mannose, galactose, xylose, arabinose, rhamnose, and so forth. D. huoshanense is regarded as a natural remedy for enhancing immunity. DHPs exhibit significant immunomodulatory effects, enhancing immunity and inhibiting tumor cell growth. They also possess antioxidant, liver-protective, anti-inflammatory, and hypoglycemic effects. The main extraction methods for DHPs include water extraction, ultrasonic- and microwave-assisted extraction, and enzyme extraction. Different extraction methods and conditions significantly influence the yield and purity of polysaccharides, with modern extraction technologies generally exhibiting higher extraction efficiencies. This study aimed to comprehensively review the research progress of DHPs in recent years, covering extraction and separation methods, structural characterization, biological activity, and structure-activity relationship. It provides a foundation for optimizing efficient extraction and purification of polysaccharides in the future, further elucidating their structure-activity relationship and investigating their mechanism of action. Moreover, this study is expected to provide valuable references for advancing research on the pharmacological activities of DHPs, such as immune regulation, promoting innovative approaches, such as multi-target coordinated regulation, and supporting the development of polysaccharide-based health foods.