Comparison of behavioral, neuroprotective, and proinflammatory cytokine modulating effects exercised by (+)-cis-EC and (-)-cis-EC stereoisomers in a PTZ-induced kindling test in mice

Fundam Clin Pharmacol. 2018 Oct;32(5):507-515. doi: 10.1111/fcp.12366. Epub 2018 May 8.

Abstract

Epoxy-carvone (EC) has chiral centers that allow generation of stereoisomers, including (+)-cis-EC and (-)-cis-EC, whose effects in the kindling tests have never been studied. Accordingly, this study aims to comparatively investigate the effect of stereoisomers (+)-cis-epoxy-carvone and (-)-cis-epoxy-carvone on behavioral changes measured in scores, in the levels of cytokines (IL-1β, IL-6, and TNFα) and neuronal protection in the face of continuous treatment with pentylenetetrazol. Swiss mice were divided into five groups (n = 10), receiving vehicle, (+) - cis-EC, (-) - cis-EC (both at the dose of 30 mg/kg), and diazepam (4 mg/kg). Thirty minutes after the respective treatment was administered to the animals one subconvulsive dose of PTZ (35 mg/kg). Seven subconvulsives treatments were made on alternate days, in which each treatment several parameters were recorded. In the eighth treatment, the animals receiving the highest dose of PTZ (75 mg/kg) and were sacrificed for quantification of cytokines and histopathologic analysis. All drugs were administered by intraperitoneal route. In the kindling test, (+)-cis-EC and (-)-cis-EC reduced the average scores. The stereoisomer (+)-cis-EC decreased levels of proinflammatory cytokines IL-1β, IL-6, and TNFα, whereas comparatively (-)-cis-EC did not reduce IL-1β levels. Histopathological analysis of the mice hippocampi undergoing this methodology showed neural protection for treated with (+)-cis-EC. The results suggest that the anticonvulsant effect of (+)-cis-EC possibly takes place due to reduction of proinflammatory cytokines involved in the epileptogenic process, besides neuronal protection, yet further investigation of the mechanisms involved is required.

Keywords: (+)-cis-epoxy-carvone; (−)-cis-epoxy-carvone; anticonvulsant; kindling; monoterpene.

MeSH terms

  • Animals
  • Anticonvulsants / chemistry
  • Anticonvulsants / pharmacology*
  • Behavior, Animal / drug effects
  • Cyclohexane Monoterpenes
  • Cytokines / drug effects
  • Kindling, Neurologic / drug effects*
  • Mice
  • Monoterpenes / chemistry
  • Monoterpenes / pharmacology*
  • Neuroprotection / drug effects*
  • Pentylenetetrazole / pharmacology
  • Stereoisomerism

Substances

  • Anticonvulsants
  • Cyclohexane Monoterpenes
  • Cytokines
  • Monoterpenes
  • carvone
  • Pentylenetetrazole