Abstract: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.
