Abstract: This study was performed in order to explore the correlation between the monosaccharide composition and hypoglycemic activity of Berberi dasystachya polysaccharides (BDPs). BDPs were extracted with hot water from B. dasystachya fruit from five regions of Qinghai province (I–V). The chemical compositions and primary structures of BDPs were determined, and their in vitro hypoglycemic activity was evaluated in terms of α-glucosidase and α-amylase inhibitory activities, and their protective effect against apoptosis induced by glucolipotoxicity (GLTy) in RIN-m5F cells was assessed. The results showed that BDPs were heteropolysaccharides connected by β-glycosidic bonds that had apyranose backbone without a triple-helix conformation, and exhibited excellent thermal stability at temperatures below 200 ℃. In addition, the monosaccharide composition and molecular mass of BDPs varied significantly depending on geographical origin. BDP-I showed good hypoglycemic activity in vitro, and the inhibitory rate of BDP-I on α-amylase was as high as 67.41% (P < 0.05). BDPs exhibited good protective effects on GLTY-induced apoptosis in RIN-m5F cells, and BDP-I had the best cell proliferation-promoting activity, which effectively decreased the levels of reactive oxygen species (ROS) and tumor necrosis factor-α (TNF-α). Finally, correlation analysis showed that monosaccharides such as glucose (Glc), galactose (Gal), rhamnose (Rha) exhibited a strongly positive correlation with hypoglycemic activity in vitro, and there was a strongly negative correlation between mannose (Man) and ROS levels. This study provides a theoretical basis for the utilization and development of B. dasystachya Maxim. berry in terms of hypoglycemic activity.

Key words: Berberi dasystachya polysaccharides; monosaccharide; RIN-m5F cells; in vitro hypoglycemic activity; glucolipotoxicity; correlation analysis