Effects of different extraction methods on the structural characterization and bioactivities of polysaccharides extracted from Polygonatum sibiricum

Polygonatum sibiricum is a traditional Chinese medicine with homology of medicine and food. Exploring different methods for extracting polysaccharides from Polygonatum sibiricum will provide broader insights into the study of its structural characteristics and biological activities. In this study, polysaccharides (PSPs) were extracted from by different methods with water (cold and hot), alcohol solutions (different concentrations) under ultrasound. The structure characterization of PSPs was mainly composed of Glc, Man and Gal with different molar ratio. HPLC data showed that the glycosidic bond of PSPs existed in α, β-D-configurations. Congo red experiment indicated that PSPs had similar triple helix structure. The PSPs extracted by different methods had different biological activities. PSP-5 had the best ability to inhibit AChE activity, and its mechanism was further explored. Results showed AChE inhibitory activity of PSP-5 was reversible, and the inhibitory mechanism was mixed type I competitive inhibition. Compared with the AChE inhibitors, PSP-5 had the potential to become an excellent AChE inhibitor.