Carboxymethylation of paramylon derived from Euglena gracilis and its hypoglycemic mechanism in diabetic mice

Paramylon is a polysaccharide primarily composed of β-1,3-glucan, characterized by its high crystallinity and insolubility in water. Enhancing its water solubility through structural modifications presents an effective strategy to unlock its biological activity. In this study, carboxymethylation was employed to produce carboxymethylated paramylon (CEP) with varying carboxyl concentrations. The successful introduction of carboxyl groups led to a notable improvement in water solubility. In vivo experiments demonstrated that CEP reduced fasting blood glucose levels by 24.42 %, improved oral glucose tolerance, and enhanced insulin sensitivity in diabetic mice. Additionally, CEP regulated lipid homeostasis and ameliorated liver damage. Through modulation of the adenosine monophosphate-activated protein kinase/phosphoinositide 3-kinase/protein kinase B pathway and the glucose-6-phosphatase/phosphoenolpyruvate carboxykinase pathway, CEP effectively regulated hepatic glucose absorption and production. Furthermore, CEP mitigated diabetes-induced lipid metabolism disorders. These findings suggest that CEP holds significant promise in ameliorating glucose metabolism disorder, indicating its potential as a novel hypoglycemic functional food.