Characterization of Water-Soluble Oxidized Paramylon and Its Hypoglycemic Effects by Alleviating Insulin Resistance

Paramylon (EP) is a type of β-glucan found in Euglena gracilis, which is characterized by a crystalline structure and insolubility, thereby limiting its practical applications. This study aimed to enhance its utility by preparing water-soluble oxidized EP (OEP) using a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation process. When compared with EP, OEP was found to boost glucose intake in insulin-resistant cells while increasing insulin receptor substrate 1 (IRS1) and glucose transporter 4 (GLUT4) levels. OEP effectively reduced fasting blood glucose levels in diabetic mice from 13.41 to 8.86 mmol L–1. OEP protected the liver from damage by enhancing hepatic glucose absorption through modulation of the IRS1/GLUT4 signaling pathway. OEP adjusted hepatic lipid composition, reducing the accumulation of diglycerides and triglycerides, ultimately ameliorating diabetes. Therefore, the OEP demonstrates significant potential as a nutritional substance for regulating blood glucose levels.