Currently, the synthesis of polysaccharide metal ion complex is predominantly categorized into three approaches: chemical synthesis, physical synthesis and biosynthesis method. According to research, polysaccharide metal ion complexes usually exhibit superior biological activities than metal ions or polysaccharides alone, including antioxidant, hypoglycemic, hypolipidemic, immune regulation, anti-tumor, anti-inflammatory and antibacterial activities. In this paper, the preparation process, biological activity and structural characteristics of polysaccharide metal ion complexes were reviewed, aiming to provide references for the development of new therapeutic drugs and adjuvants. And the complexation of Tremella fuciformis polysaccharides and metal ions was prospected.

Tremella fuciformis polysaccharide (TFP) is an important bioactive substance in T. fuciformis, which contributes to its application as medicine and food. In the present work, TFP was extracted with enzymatic combined with wet beating and its physicochemical as well as biological activities were investigated in the study. The result showed that the purity of TFP1 reached 92.14% (m/m). The TFP1, purified by DEAE column, had a molecular weight (M_w) of 5.8 × 10³ kDa and consisted mainly of mannose, xylose, fucose, glucose and glucuronic acid at a molar ratio of 1.91: 0.1: 2.49: 6.23: 0.95. The structure of TFP1 was preliminarily investigated by infrared spectroscopy, nuclear magnetic resonance and atomic force microscope (AFM) analysis. Moreover, the antioxidant assays showed that TFP1 could scavenge DPPH, ABTS⁺ and hydroxyl radicals. The excellent water holding capacity of TFP1 implied its application in the food, pharmaceutical andcosmetic industries.