为了探究余甘子多糖的构效关系,采用热水提取余甘子多糖,用50%和80%乙醇分级醇沉获得两个组分(PEP-50和PEP-80)。PEP-50和PEP-80均具有相同的单糖组成,但含量具有一定的差异,其中半乳糖醛酸为主要成分；且PEP-80组分的分子量主要为234.45 kDa,占99.21%,低于PEP-50(256.26 kDa,92.51%)。同时,PEP-50和PEP-80均具有降糖活性,对α-葡萄糖苷酶的半抑制浓度分别为3.34和0.46 mg/mL,均以混合型抑制的方式起到抑制作用。其中PEP-80的降糖活性大于PEP-50,表现出对游离α-葡萄糖苷酶的结合以及对α-葡萄糖苷酶-底物复合物的结合能力均强于PEP-50,这些差异与其不同的化学组成及分子量密切相关。以上实验表明,分子量对余甘子多糖降血糖功能活性具有重要的影响,也为今后开发不同类型的余甘子健康食品提供了理论依据。

To realize the relationship between structure and activity, this study extracted Phyllanthus emblica L. polysaccharides by hot water and precipitated them by 50% and 80% ethanol into two fractions (PEP-50 and PEP-80). PEP-50 and PEP-80 were made up of comparable types of monosaccharides in varying quantities in which galacturonic acid was the main constituent. Besides, the molecular weight of PEP-80 was mainly distributed in 234.45 kDa (accounting for 99.21%), which was lower than PEP-50 that mainly distributed in 256.26 kDa (accounting for 92.51%). Moreover, PEP-50 and PEP-80 had hypoglycemic activity, and the IC50 values were 3.34 and 0.46 mg/mL respectively. Both of them exhibited a mixed-type inhibition of α-glucosidase. In addition, PEP-80 had stronger inhibitory effects on α-glucosidase than PEP-50, exhibiting stronger binding ability to α-glucosidase and α-glucosidase-substrate complex. These differences might be closely related to different chemical composition and molecular weight. These data suggest the molecular weight of Phyllanthus emblica L. polysaccharides had great impact on their hypoglycemic activity, providing important theoretical guiding significant for developing Phyllanthus emblica L. food products with different types.

植物多酚与活性多糖协同降血糖研究及健康焙烤食品的开发