Abstract:The content of Bletillɑ striɑtɑ polysaccharides was determined by the phenol-sulfuric acid method，the monosaccharide composition was measured by the ion chromatography method， and the dynamic parameters of inhibiting tyrosinase activity of Bletillɑ striɑtɑ polysaccharides were obtained by adopting the enzymolysis assay. The results showed that the content of Bletillɑ striɑtɑ polysaccharides extracted by the multi-enzyme method was （51.97±1.52）%. By employing ion chromatography， the study found that the monosaccharide composition of Bletillɑ striɑtɑ polysaccharides included seven kinds： Rha， Ara， Gal， Glc， Man， GAL-UA and GLc-UA， and the proportions of monosaccharides were 0.17%， 0.36%， 1.86%， 41.81%， 54.21%， 0.71%，and 0.88% respectively. In vitro， Bletillɑ striɑtɑ polysaccharides exerted an inhibitory effect on tyrosinase’s activity， with the IC50 of Bletillɑ striɑtɑ polysaccharides being 59.31 mg/mL. Additionally， Bletillɑ striɑtɑ polysaccharides could reduce the initial reaction speed of tyrosinase， which indicated that Bletillɑ striɑtɑ polysaccharides had a delayed effect on the catalysis of tyrosinase. Meanwhile， with the increasing mass concentration of Bletillɑ striɑtɑ polysaccharides， they had a stronger inhibition effect on tyrosinase′s activity， with the characteristics of dose-dependency and reversibility. The Lineweaver-Burk double-reciprocal curve showed that with the rising mass concentration of Bletillɑ striɑtɑ polysaccharides， the value of the Michaelis constant Km gradually increased， while Vmax gradually decreased. This indicated that the inhibitory effect of Bletillɑ striɑtɑ polysaccharides on tyrosinase was a type of non-competitive and competitive mixed inhibition.