Differential inhibitory effects of honokiol and magnolol on excitatory amino acid-evoked cation signals and NMDA-induced seizures

Neuropharmacology. 2005 Sep;49(4):542-50. doi: 10.1016/j.neuropharm.2005.04.009.


The effects of honokiol and magnolol, two major bioactive constituents of the bark of Magnolia officinalis, on Ca(2+) and Na(+) influx induced by various stimulants were investigated in cultured rat cerebellar granule cells by single-cell fura-2 or SBFI microfluorimetry. Honokiol and magnolol blocked the glutamate- and KCl-evoked Ca(2+) influx with similar potency and efficacy, but did not affect KCl-evoked Na(+) influx. However, honokiol was more specific for blocking NMDA-induced Ca(2+) influx, whereas magnolol influenced with both NMDA- and non-NMDA activated Ca(2+) and Na(+) influx. Moreover, the anti-convulsant effects of these two compounds on NMDA-induced seizures were also evaluated. After honokiol or magnolol (1 and 5 mg/kg, i.p.) pretreatment, the seizure thresholds of NMRI mice were determined by tail-vein infusion of NMDA (10 mg/ml). Data showed that both honokiol and magnolol significantly increased the NMDA-induced seizure thresholds, and honokiol was more potent than magnolol. These results demonstrated that magnolol and honokiol have differential effects on NMDA and non-NMDA receptors, suggesting that the distinct therapeutic applications of these two compounds for neuroprotection should be considered.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animals
  • Anti-Anxiety Agents / chemistry
  • Anti-Anxiety Agents / therapeutic use*
  • Biphenyl Compounds / chemistry
  • Biphenyl Compounds / therapeutic use*
  • Calcium / metabolism
  • Cells, Cultured
  • Cerebellum / cytology
  • Disease Models, Animal
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Excitatory Amino Acid Agonists / pharmacology*
  • Excitatory Amino Acid Antagonists / pharmacology
  • Ion Channels / drug effects*
  • Lignans / chemistry
  • Lignans / therapeutic use*
  • Mice
  • N-Methylaspartate
  • Neurons / drug effects
  • Platelet Aggregation Inhibitors / chemistry
  • Platelet Aggregation Inhibitors / therapeutic use*
  • Potassium Chloride / pharmacology
  • Quinoxalines / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Seizures / chemically induced
  • Seizures / drug therapy*
  • Sodium / metabolism


  • Anti-Anxiety Agents
  • Biphenyl Compounds
  • Excitatory Amino Acid Agonists
  • Excitatory Amino Acid Antagonists
  • Ion Channels
  • Lignans
  • Platelet Aggregation Inhibitors
  • Quinoxalines
  • magnolol
  • honokiol
  • FG 9041
  • N-Methylaspartate
  • Potassium Chloride
  • Sodium
  • Calcium