Novel multi-target compounds in the quest for new chemotherapies against Alzheimer's disease: An experimental and theoretical study

Research output: Contribution to journalArticle

Abstract

The lack of any effective therapy along with the aging world population anticipates a growth of the worldwide incidence of Alzheimer's disease (AD) to more than 100 million cases by 2050. Accumulation of extracellular amyloid-β (Aβ) plaques, intracellular tangles in the brain, and formation of reactive oxygen species (ROS) are the major hallmarks of the disease. In the amyloidogenic process, a β-secretase, known as BACE 1, plays a fundamental role in the production of Aβ fragments, and therefore, inhibition of such enzymes represents a major strategy for the rational design of anti-AD drugs. In this work, a series of four multi-target compounds (1–4), inspired by previously described ionophoric polyphenols, have been synthesized and studied. These compounds have been designed to target important aspects of AD, including BACE 1 enzymatic activity, Aβ aggregation, toxic concentrations of Cu2+ metal ions and/or ROS production. Two other compounds (5 and 6), previously reported by some of us as antimalarial agents, have also been studied because of their potential as multi-target species against AD. Interestingly, compounds 3 and 5 showed moderate to good ability to inhibit BACE 1 enzymatic activity in a FRET assay, with IC50′s in the low micromolar range (4.4 ± 0.3 and 1.7 ± 0.3 μM, respectively), comparable to other multi-target species, and showing that the observed activity was in part due to a competitive binding of the compounds at the active site of the enzyme. Theoretical docking calculations overall agreed with FRET assay results, displaying the strongest binding affinities for 3 and 5 at the active site of the enzyme. In addition, all compounds selectively interacted with Cu2+ metal ions forming 2:1 complexes, inhibited the production of Aβ-Cu2+ catalyzed hydroxyl radicals up to a ∼100% extent, and scavenged AAPH-induced peroxyl radical species comparably to resveratrol, a compound used as reference in this work. Our results also show good anti-amyloidogenic ability: compounds 1–6 inhibited both the Cu2+-induced and self-induced Aβ(1–40) fibril aggregation to an extent that ranged from 31% to 77%, while they disaggregated pre-formed Aβ(1–40) mature fibrils up to a 37% and a 69% extent in absence and presence of Cu2+, respectively. Cytotoxicity was additionally studied in Tetrahymena thermophila and HEK293 cells, and compared to that of resveratrol, showing that compounds 1–6 display lower toxicity than that of resveratrol, a well-known non-toxic polyphenol.

Details

Authors
  • Alberto Martínez
  • Mai Zahran
  • Miguel Gomez
  • Coreen Cooper
  • Johnny Guevara
  • Erik Ekengard
  • Ebbe Nordlander
  • Ralph Alcendor
  • Sarah Hambleton
Organisations
External organisations
  • City University of New York
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Pharmaceutical Sciences

Keywords

  • Alzheimer's disease, Amyloid-beta aggregation, Antioxidant, BACE1, Docking, Ionophoric compound, Molecular design, Multi-target compound, Polyphenol, Reactive oxygen species, Tetrahymena, β-secretase inhibitor
Original languageEnglish
Pages (from-to)4823-4840
Number of pages18
JournalBioorganic and Medicinal Chemistry
Volume26
Issue number17
Publication statusPublished - 2018 Sep 15
Publication categoryResearch
Peer-reviewedYes