香菇多糖的化学修饰及结构表征

为明确改性效果,本文选择适宜的方法对香菇多糖分子结构进行了化学修饰和结构表征.选用氯磺酸-吡啶法和浓硫酸法对香菇多糖硫酸酯化,并进行了比较,利用一氯乙酸法对其进行羧甲基化,借助红外光谱和核磁共振碳谱对样品分别进行了结构表征.结果表明,氯磺酸-吡啶法硫酸化取代度达1.38,产率达79.23%,硫含量达14.59%,效果优于浓硫酸法;1247和807 cm~(-1)的特征吸收峰证明了硫酸基的引入,碳谱δ 79.06附近的峰证明了C2和C4被部分硫酸基取代;羧甲基化碳谱中C2和C4位附近出峰说明其位上羟基被取代,且异头碳为单一β-D-吡喃环糖苷键构型.通过红外光谱和核磁共振碳谱对香菇多糖结构表征证实,硫酸酯化和羧甲基化二种化学修饰方法对香菇多糖分子结构改性是可行的,且氯磺酸-吡啶法更适合香菇多糖硫酸化.

Chemical Modification and Structure Characterization of Lentinan

The processes of sulfation modification of lentinan were conducted with chlosulfonic-pyridine and concentrated sulfuric acid methods,which were compared correspondingly.Carboxymethyl lentinans were treated with monochloroacetic acid and then the structure characterization was employed to identify the modification effect by using IR and 13C NMR.The substitution degree of it with chlosulfonic-pyridine method was better than that of concentrated sulfuric acid method with 79.23% yield and 14.59% sulfur contents.Sulfate groups were introduced successfully with the absorbance of 1247 and 807 cm-1 IR spectrum.The absorbance of δ79.06 showed that hydroxyl groups of C2 and C4 were partly substituted by sulfate groups.The absorbance nearby C2 and C4 identified that hydroxyl groups had been replaced by carboxymethyl group,which also elucidated the β-D-pyranoside configuration of its anomeric carbon.It' s feasible to modify the molecular structure of lentinan by sulfate and carboxymethyl reagents through IR and ~(13)C NMR spectral studies.