Cell signaling pathways in the mechanisms of neuroprotection afforded by bergamot essential oil against NMDA-induced cell death in vitro

Br J Pharmacol. 2007 Jun;151(4):518-29. doi: 10.1038/sj.bjp.0707237. Epub 2007 Apr 2.


Background and purpose: The effects of bergamot essential oil (BEO; Citrus bergamia, Risso) on excitotoxic neuronal damage was investigated in vitro.

Experimental approach: The study was performed in human SH-SY5Y neuroblastoma cells exposed to N-methyl-D-aspartate (NMDA). Cell viability was measured by dye exclusion. Reactive oxygen species (ROS) and caspase-3 activity were measured fluorimetrically. Calpain I activity and the activation (phosphorylation) of Akt and glycogen synthase kinase-3beta (GSK-3beta) were assayed by Western blotting.

Key results: NMDA induced concentration-dependent, receptor-mediated, death of SH-SY5Y cells, ranging from 11 to 25% (0.25-5 mM). Cell death induced by 1 mM NMDA (21%) was preceded by a significant accumulation of intracellular ROS and by a rapid activation of the calcium-activated protease calpain I. In addition, NMDA caused a rapid deactivation of Akt kinase and this preceded the detrimental activation of the downstream kinase, GSK-3beta. BEO (0.0005-0.01%) concentration dependently reduced death of SH-SY5Y cells caused by 1 mM NMDA. In addition to preventing ROS accumulation and activation of calpain, BEO (0.01%) counteracted the deactivation of Akt and the consequent activation of GSK-3beta, induced by NMDA. Results obtained by using specific fractions of BEO, suggested that monoterpene hydrocarbons were responsible for neuroprotection afforded by BEO against NMDA-induced cell death.

Conclusions and implications: Our data demonstrate that BEO reduces neuronal damage caused in vitro by excitotoxic stimuli and that this neuroprotection was associated with prevention of injury-induced engagement of critical death pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium / metabolism
  • Cell Death / drug effects
  • Cell Line, Tumor
  • Glycogen Synthase Kinase 3 / metabolism
  • Glycogen Synthase Kinase 3 beta
  • Humans
  • N-Methylaspartate / toxicity*
  • Neurons / drug effects
  • Neurons / metabolism
  • Neuroprotective Agents / pharmacology*
  • Oils, Volatile / pharmacology*
  • Phosphatidylinositol 3-Kinases / physiology
  • Phosphorylation
  • Plant Oils / pharmacology*
  • Proto-Oncogene Proteins c-akt / metabolism
  • Signal Transduction / drug effects*


  • Neuroprotective Agents
  • Oils, Volatile
  • Plant Oils
  • bergamot oil
  • N-Methylaspartate
  • Phosphatidylinositol 3-Kinases
  • GSK3B protein, human
  • Glycogen Synthase Kinase 3 beta
  • Proto-Oncogene Proteins c-akt
  • Glycogen Synthase Kinase 3
  • Calcium