Extraction, purification, characteristics, bioactivities, application, and toxicity of Gastrodia R. Br. polysaccharides: A review.

Gastrodia elata BL. is a dried tuber of the orchid plant Gastrodia R. Br., mainly distributed in Jilin, Sichuan, Guizhou, Yunnan, and other places, with wind quenching antispasmodic, suppressing the liver and Yang and other efficacy, is one of China's traditional Chinese medicinal herbs. Polysaccharides are the main bioactive substances of Gastrodia R. Br., and they have attracted extensive attention of researchers both at home and abroad. In the past few decades, various methods (such as hot water extraction, ultrasonic extraction, enzymatic extraction, etc) have been applied to extract polysaccharides from Gastrodia R. Br. (GRPs) and the structural features of GRPs are closely related to the methods of extraction and purification. Many studies have confirmed that GRPs possess various remarkable bioactivities, including anti-oxidation, anti-tumor, immune regulation, anti-aging, improving cerebral ischemia, improving memory, lowering blood pressure and glucose, anti-bacterial activities, etc. GRP, as a natural polysaccharide, is widely used in the fields of medicine, food, and health products, and has important research and development value. However, the intrinsic relationship and mechanism of action between its advanced structure and pharmacological effects need further in-depth study. This paper systematically reviews the research on the extraction and purification, structural characteristics, biological activity, modification, and potential applications of GRPs in recent years, providing a theoretical basis for further studying the structure-activity relationship of GRPs and their applications as therapeutic agents and functional foods.