Substituted piperazine conjugated to quinoline-thiosemicarbazide as potent α-glucosidase inhibitors to target hyperglycemia

Sci Rep. 2025 Jan 13;15(1):1871. doi: 10.1038/s41598-024-83917-z.

Abstract

Diabetes mellitus, particularly type 2 diabetes, is a growing global health challenge characterized by chronic hyperglycemia due to insulin resistance. One therapeutic approach to managing this condition is the inhibition of α-glucosidase, an enzyme involved in carbohydrate digestion, to reduce postprandial blood glucose levels. In this study, a series of thiosemicarbazide-linked quinoline-piperazine derivatives were synthesized and evaluated for their α-glucosidase inhibitory activity, to identify new agents for type 2 diabetes management. Structure-activity relationship (SAR) analysis revealed that the nature and position of substituents on the aryl ring significantly impacted the inhibitory potency. Among the synthesized derivatives, the 2,5-dimethoxy phenyl substitution (7j) exhibited the most potent activity with an IC50 value of 50.0 µM, demonstrating a 15-fold improvement compared to the standard drug acarbose. Kinetic studies identified compound 7j as a competitive inhibitor, with a Ki value of 32 µM. Molecular docking simulations demonstrated key interactions between compound 7j and the active site of α-glucosidase, while molecular dynamics simulations confirmed the stability of the enzyme-ligand complex, reflected in low RMSD and RMSF values.

Keywords: Diabetes mellitus; Quinoline-piperazine; Thiosemicarbazide; Α-glucosidase.

MeSH terms

  • Catalytic Domain
  • Diabetes Mellitus, Type 2 / drug therapy
  • Glycoside Hydrolase Inhibitors* / chemical synthesis
  • Glycoside Hydrolase Inhibitors* / chemistry
  • Glycoside Hydrolase Inhibitors* / pharmacology
  • Humans
  • Hyperglycemia* / drug therapy
  • Hypoglycemic Agents / chemistry
  • Hypoglycemic Agents / pharmacology
  • Kinetics
  • Molecular Docking Simulation*
  • Molecular Dynamics Simulation
  • Piperazine / chemistry
  • Piperazine / pharmacology
  • Piperazines / chemistry
  • Piperazines / pharmacology
  • Quinolines* / chemistry
  • Quinolines* / pharmacology
  • Semicarbazides* / chemistry
  • Semicarbazides* / pharmacology
  • Structure-Activity Relationship
  • alpha-Glucosidases* / chemistry
  • alpha-Glucosidases* / metabolism

Substances

  • Glycoside Hydrolase Inhibitors
  • Semicarbazides
  • alpha-Glucosidases
  • thiosemicarbazide
  • Quinolines
  • Piperazine
  • Hypoglycemic Agents
  • Piperazines
  • quinoline