Donut-shaped [NaP5W30O110]14− polyoxometalate as a promising antidiabetic drug-candidate: putative mechanisms of action

Abstract

The aim of this study was to elucidate the potential mechanism of the antihyperglycemic action of the donut-shaped Preyssler-Pope-Jeannin polyanion salt (NH4)14[NaP5W30O110] 31H2O (NaP5W30) and its effect on metabolic disorders associated with diabetes. For this purpose, relevant parameters of blood glucose regulation, lipid profile, and electrolyte status were monitored in streptozotocin (STZ)-induced diabetic rats that were orally treated with 20 mg/kg/day NaP5W30 for three weeks. The serum insulin concentration was increased in diabetic animals treated with NaP5W30 (20 mg/kg/day, per os, three weeks), which could be one of the possible mechanisms of the confirmed antihyperglycemic effect. In addition, the administration of NaP5W30 significantly reduced hyperglycemia and glycated haemoglobin A1c (HbA1c) in STZ-induced diabetic rats, although normoglycemic values were not achieved. Furthermore, a statistically significant 1.3-fold reduction in serum total cholesterol and a 1.7-fold reduction in high-density lipoprotein (HDL) cholesterol were observed in the NaP5W30 treatment group compared to the diabetic control group. In contrast, NaP5W30 had no effect on homeostasis model assessment of insulin resistance (HOMA-IR) index values, electrolyte concentrations, or serum concentrations of low-density lipoprotein (LDL) cholesterol, apolipoprotein A1 (Apo A1), apolipoprotein B (Apo B), or total triglycerides. In summary, NaP5W30 effectively improved glycoregulation in diabetic rats via the considerable stimulation of insulin as a putative mechanism. Moreover, NaP5W30 did not affect rat weight or disrupt lipid and electrolyte status, common diabetes-followed side effects and risk factors for various life-threatening complications. Thus, NaP5W30 could be considered a promising antidiabetic drug-candidate that deserves further investigation.