Comparative Study of Hypoglycemic Effects and Mechanisms of Crude and Wine-Processed Polysaccharides From Polygonatum sibiricum.

Polygonatum sibiricum (PS), a traditional food and medicinal plant, primarily consists of PS polysaccharides (PSP), which have been documented to possess hypoglycemic properties. Despite the fact that wine-processed PSP (PSPW) represents the predominant form utilized in clinical applications of PS, research has predominantly concentrated on its crude PSC (PSPC). The exact pathways responsible for the hypoglycemic effects of PSPW need further elucidation. To evaluate the hypoglycemic effects and related mechanisms of PSPC and PSPW, we applied PSPC and PSPW to an oxidative stress injury model using HepG2 cells and a T2DM rat model induced by streptozotocin (STZ). Data showed that both PSPC and PSPW can decrease the glucose oxidase (GOD) activity and reduce ROS levels in the oxidative stress injury model of HepG2 cells. Furthermore, PSPC and PSPW can not only ameliorate liver and kidney damage in T2DM rats, but also significantly improve symptoms such as FBG and weight loss. They can also reduce the activities of TG, TC, and GSP in serum, increase the activities of NEFA and INS, and upregulate the mRNA expression levels of PI3K, AKT, INSR, and GLUT-2 in liver tissue, as well as the protein expression levels of P-AKT, PI3K, p-IRS1, and GLUT-2. Moreover, the PSPW group shows a more significant improvement effect than the PSPC group. Overall, our study demonstrates that PSPC and PSPW exert their hypoglycemic effects by regulating oxidative stress and the insulin signaling pathway. Our observations aim to offer novel perspectives on PSPW's potential utilization as a therapeutic candidate and functional food components.