Synthesis and Spectral Identification of Three Schiff Bases with a 2-(Piperazin-1-yl)- N-(thiophen-2-yl methylene)ethanamine Moiety Acting as Novel Pancreatic Lipase Inhibitors: Thermal, DFT, Antioxidant, Antibacterial, and Molecular Docking Investigations

Molecules. 2020 May 11;25(9):2253. doi: 10.3390/molecules25092253.

Abstract

Three new tetradentate NNNS Schiff bases (L1-L3) derived from 2-(piperidin-4-yl)ethanamine were prepared in high yields. UV-Visible and FTIR spectroscopy were used to monitor the dehydration reaction between 2-(piperidin-4-yl)ethanamine and the corresponding aldehydes. Structures of the derived Schiff bases were deduced by 1H and 13C NMR, FTIR, UV-Vis, MS, EA, EDS, and TG-derived physical measurements. DFT/B3LYP theoretical calculations for optimization, TD-DFT, frequency, Molecular Electrostatic Potential (MEP), and highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) / were performed for L2. The in vitro antimicrobial activities of the three Schiff bases were evaluated against several types of bacteria by disk diffusion test using Gentamicin as the standard antibiotic. Schiff bases revealed good antioxidant activity by the DPPH method, and the IC50 values were compared to the Trolox standard. Pancreatic porcine lipase inhibition assay of the synthesized compounds revealed promising activity as compared to the Orlistat reference.

Keywords: DFT; Schiff base; antimicrobial; pancreatic lipase inhibitors.

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Antioxidants / pharmacology*
  • Inhibitory Concentration 50
  • Klebsiella pneumoniae / drug effects
  • Ligands
  • Lipase / antagonists & inhibitors*
  • Magnetic Resonance Spectroscopy
  • Mass Spectrometry
  • Molecular Docking Simulation
  • Pancreas / enzymology
  • Piperazine / chemistry
  • Pseudomonas aeruginosa / drug effects
  • Schiff Bases / chemical synthesis*
  • Schiff Bases / chemistry*
  • Schiff Bases / pharmacology
  • Spectrophotometry, Ultraviolet
  • Spectroscopy, Fourier Transform Infrared
  • Staphylococcus aureus / drug effects
  • Static Electricity
  • Temperature
  • Thiophenes / chemistry
  • X-Ray Diffraction

Substances

  • Anti-Bacterial Agents
  • Antioxidants
  • Ligands
  • Schiff Bases
  • Thiophenes
  • Piperazine
  • Lipase