Design, synthesis, and biological evaluation of 3-(1-Aryl-1H-indol-5-yl)propanoic acids as new indole-based cytosolic phospholipase A2α inhibitors

J Med Chem. 2014 Sep 11;57(17):7244-62. doi: 10.1021/jm500494y. Epub 2014 Aug 26.

Abstract

This article describes the design, synthesis, and biological evaluation of new indole-based cytosolic phospholipase A2α (cPLA2α, a group IVA phospholipase A2) inhibitors. A screening-hit compound from our library, (E)-3-{4-[(4-chlorophenyl)thio]-3-nitrophenyl}acrylic acid (5), was used to design a class of 3-(1-aryl-1H-indol-5-yl)propanoic acids as new small molecule inhibitors. The resultant structure-activity relationships studied using the isolated enzyme and by cell-based assays revealed that the 1-(p-O-substituted)phenyl, 3-phenylethyl, and 5-propanoic acid groups on the indole core are essential for good inhibitory activity against cPLA2α. Optimization of the p-substituents on the N1 phenyl group led to the discovery of 56n (ASB14780), which was shown to be a potent inhibitor of cPLA2α via enzyme assay, cell-based assay, and guinea pig and human whole-blood assays. It displayed oral efficacy toward mice tetradecanoyl phorbol acetate-induced ear edema and guinea pig ovalbumin-induced asthma models.

MeSH terms

  • Animals
  • Area Under Curve
  • Asthma / chemically induced
  • Asthma / prevention & control
  • Cytosol / enzymology
  • Dogs
  • Drug Design*
  • Edema / chemically induced
  • Edema / prevention & control
  • Enzyme Inhibitors / chemical synthesis
  • Enzyme Inhibitors / pharmacokinetics
  • Enzyme Inhibitors / pharmacology*
  • Female
  • Group IV Phospholipases A2 / antagonists & inhibitors*
  • Group IV Phospholipases A2 / metabolism
  • Guinea Pigs
  • Haplorhini
  • Humans
  • Indoles / chemical synthesis
  • Indoles / chemistry
  • Indoles / pharmacokinetics
  • Indoles / pharmacology*
  • Male
  • Metabolic Clearance Rate
  • Mice
  • Mice, Inbred C57BL
  • Models, Chemical
  • Molecular Structure
  • Ovalbumin
  • Propionates / chemical synthesis
  • Propionates / pharmacokinetics
  • Propionates / pharmacology*
  • Structure-Activity Relationship
  • Tetradecanoylphorbol Acetate
  • U937 Cells

Substances

  • 3-(1-(4-phenoxyphenyl)-3-(2-phenylethyl)-1H-indol-5-yl)propanoic acid
  • Enzyme Inhibitors
  • Indoles
  • Propionates
  • indole
  • Ovalbumin
  • Group IV Phospholipases A2
  • propionic acid
  • Tetradecanoylphorbol Acetate