Structural Identification of Lentinus edodes Cellulose Derivative that Inhibits Aflatoxin Production by Aspergillus flavus

Purpose: To identify the structures of cellulose-extract derivative (CED) formed by heating Lentinus edodes cellulose in water surroundings that can efficiently inhibit aflatoxin production by Aspergillus flavus. Methods: CED was purified on Sepharose CL-6B columns, and then structurally characterized using amino acid analyzer, gas chromatography, Fourier transform infrared spectroscopy, and polyacrylamide gel electrophoresis. Results: CED completely inhibited aflatoxin AFB1 production by A. flavus at concentrations ≥ 100 μg/ mL. Chemical analysis indicated that CED contained 82 % carbohydrate and 18 % protein and has a molecular weight of approximately 24 kDa. Monosaccharide component analysis indicates that glucose was the predominant monosaccharide of CED. Analysis by Smith degradation and enzymatic hydrolysis indicate that there were only (1, 4)-glycosidic linkages in the CED polysaccharide chains. The protein backbone of CED contained 15 kinds of amino acid with higher levels of glutamic acid, aspartic acid, leucine and alanine. Conclusion: CED was identified as a complex of peptide and polysaccharide structures possessing β(1, 4)-glucan backbones, and it provides a theoretical basis for developing polysaccharide preparations to control aflatoxin contamination with medical and food science applications.