Extraction, purification, structural features, biological activities, and applications of polysaccharides from Opuntia ficus-indica (L.) Mill. (cactus): a review - Liu, Xudong; Xing, Yan; Liu, Guijun; Bao, Dapeng; Hu, Wenjing; Bi, Haizheng; Wang, Meng (Frontiers in Pharmacology, 2025)