香菇多糖的成分及其分子量研究

Studies on Components and Molecular Weights of Polysaccharides from Lentinus Edodes

从香菇子实体中用０．９％ＮａＣｌ水溶液、８５％乙醇、热水、１％草酸铵、５％ＮａＯＨ／０．０５％ＮａＢＨ４和２％ＮａＯＨ／２％尿素分别提取出四种杂多糖（Ｌ－ＦⅠ＿Ｌ－ＦⅣｎ）和两种葡聚糖（Ｌ－ＦⅤ和Ｌ－ＦⅥｎ）．红外光谱和高效液相色谱分析结果表明杂多糖主要由葡萄糖、葡萄糖醛酸、木糖、甘露糖、半乳糖和鼠李糖组成，而且按照分离过程的进行多糖中葡萄糖含量递增．由光散射和膜渗透压法研究了多糖的重均分子量Ｍｗ、均方根旋转半径〈Ｓ２〉１／２、第二维利系数Ａ２及数均分子量Ｍｎ．Ｌ－ＦⅡ、Ｌ－ＦⅢ、Ｌ－ＦⅤ及Ｌ－ＦⅥｎ的Ｍｗ值依次为１９．７×１０４、１９２．３×１０４、１３６．４×１０４和１３６．７×１０４，它们的多分散系数Ｍｗ／Ｍｎ在３～５范围．

Four heteropolysaccharides(L FⅠ_L FⅣ n ) and two glucans(L FⅤ and L FⅥ n ) were isolated from the fruit bodies of lentinus edodes by using aqueous 0 9% NaCl, 85% ethanol, hot water(120 ℃, high pressure), aqueous 1% ammonium oxalate, aqueous 5% NaOH/0 05% NaBH 4 and 2% NaOH/2% urea, respectively. The results analyzed with IR and HPLC showed that the heteropolysaccharides consist of D glucose, glucuronic acid, xylose, mannose and galactose and rhamnose, and the D glucose content in the polysaccharides increases with the progress of isolation process. The weight average molecular weights w, root mean square radii of gyration 〈 S 2〉 1/2 , second Virial coefficients A 2 and number average molecular weights n of the polysaccharides were studied by using light scattering and membrane osmometry. The w values of the samples of L FⅡ, L FⅢ, L FⅤ and L FⅥ n are 19 7×10 4, 192 3×10 4, 136 4×10 4 and 136 7×10 4, respectively. The polydispersity indexes of the polysaccharides w/ n lie in the range of 3￣5.