Comparative Evaluation of the Antioxidant and Anti-Alzheimer's Disease Potential of Coumestrol and Puerarol Isolated from Pueraria lobata Using Molecular Modeling Studies

Molecules. 2018 Mar 28;23(4):785. doi: 10.3390/molecules23040785.


The current study assesses the antioxidant effects of two similar isoflavonoids isolated from Pueraria lobata, coumestrol and puerarol, along with the cholinergic and amyloid-cascade pathways to mitigate Alzheimer's disease (AD). Antioxidant activity was evaluated via 1,1-diphenyl-2-picryhydrazyl (DPPH) and peroxynitrite (ONOO-) scavenging ability further screened via ONOO--mediated nitrotyrosine. Similarly, acetyl- and butyrylcholinesterase (AChE/BChE) and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitory activities were assessed together with docking and kinetic studies. Considering DPPH and ONOO- scavenging activity, coumestrol (EC50 values of 53.98 and 1.17 µM) was found to be more potent than puerarol (EC50 values of 82.55 and 6.99 µM) followed by dose dependent inhibition of ONOO--mediated nitrotyrosine. Coumestrol showed pronounced AChE and BChE activity with IC50 values of 42.33 and 24.64 µM, respectively, acting as a dual cholinesterase (ChE) inhibitor. Despite having weak ChE inhibitory activity, puerarol showed potent BACE1 inhibition (28.17 µM). Kinetic studies of coumestrol showed AChE and BChE inhibition in a competitive and mixed fashion, whereas puerarol showed mixed inhibition for BACE1. In addition, docking simulations demonstrated high affinity and tight binding capacity towards the active site of the enzymes. In summary, we undertook a comparative study of two similar isoflavonoids differing only by a single aliphatic side chain and demonstrated that antioxidant agents coumestrol and puerarol are promising, potentially complementary therapeutics for AD.

Keywords: Alzheimer’s disease; BACE1; cholinesterase; kinetics; molecular docking.

Publication types

  • Comparative Study

MeSH terms

  • Acetylcholinesterase / chemistry
  • Alzheimer Disease / drug therapy*
  • Amyloid Precursor Protein Secretases* / antagonists & inhibitors
  • Amyloid Precursor Protein Secretases* / chemistry
  • Animals
  • Antioxidants* / chemistry
  • Antioxidants* / isolation & purification
  • Aspartic Acid Endopeptidases* / antagonists & inhibitors
  • Aspartic Acid Endopeptidases* / chemistry
  • Butyrylcholinesterase / chemistry
  • Coumestrol* / chemistry
  • Coumestrol* / isolation & purification
  • Electrophorus
  • Fish Proteins / chemistry
  • Horses
  • Humans
  • Molecular Docking Simulation*
  • Pueraria / chemistry*


  • Antioxidants
  • Fish Proteins
  • Acetylcholinesterase
  • Butyrylcholinesterase
  • Amyloid Precursor Protein Secretases
  • Aspartic Acid Endopeptidases
  • BACE1 protein, human
  • Coumestrol