Anti-neuroinflammatory properties of synthetic cryptolepine in human neuroblastoma cells: possible involvement of NF-κB and p38 MAPK inhibition

Eur J Med Chem. 2013 May:63:333-9. doi: 10.1016/j.ejmech.2013.02.004. Epub 2013 Feb 19.


Cryptolepis sanguinolenta and its bioactive alkaloid, cryptolepine have shown anti-inflammatory activity. However, the underlying mechanism of anti-inflammatory action in neuronal cells has not been investigated. In the present study we evaluated an extract of C. sanguinolenta (CSE) and cryptolepine (CAS) on neuroinflammation induced with IL-1β in SK-N-SH neuroblastoma cells. We then attempted to elucidate the mechanisms underlying the anti-neuroinflammatory effects of CAS in SK-N-SH cells. Cells were stimulated with 10 U/ml of IL-1β in the presence or absence of different concentrations of CSE (25-200 μg/ml) and CAS (2.5-20 μM). After 24 h incubation, culture media were collected to measure the production of PGE2 and the pro-inflammatory cytokines (TNFα and IL-6). Protein and gene expressions of cyclooxygenase (COX-2) and microsomal prostaglandin synthase-1 (mPGES-1) were studied by immunoblotting and qPCR, respectively. CSE produced significant (p < 0.05) inhibition of TNFα, IL-6 and PGE2 production in SK-N-SH cells. Studies on CAS showed significant and dose-dependent inhibition of TNFα, IL-6 and PGE2 production in IL-1β-stimulated cells without affecting viability. Pre-treatment with CAS (10 and 20 μM) was also found to inhibit IL-1β-induced protein and gene expressions of COX-2 and mPGES-1. Further studies to determine the mechanism of action of CAS showed inhibition of NF-κBp65 nuclear translocation, but not IκB phosphorylation. At 10 and 20 μM, CAS inhibited IL-1β-induced phosphorylation of p38 MAPK. Studies on the downstream substrate of p38, MAPK-activated protein kinase 2 (MAPKAPK2) showed that CAS produced significant (p < 0.05) and dose dependent inhibition of MAPKAPK2 phosphorylation in IL-1β-stimulated SK-N-SH cells. This study clearly shows that cryptolepine (CAS) inhibits neuroinflammation through mechanisms involving inhibition of COX-2 and mPGES-1. It is suggested that these actions are probably mediated through NF-κB and p38 signalling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus / drug effects
  • Anti-Inflammatory Agents / chemical synthesis
  • Anti-Inflammatory Agents / chemistry
  • Anti-Inflammatory Agents / pharmacology*
  • Cell Line, Tumor
  • Cryptolepis / chemistry
  • Cyclooxygenase 2 / genetics
  • Cyclooxygenase 2 / metabolism
  • Cytokines / metabolism
  • Dinoprostone / metabolism
  • Dose-Response Relationship, Drug
  • Gene Expression Regulation, Enzymologic / drug effects
  • Humans
  • Immunoblotting
  • Indole Alkaloids / chemical synthesis
  • Indole Alkaloids / chemistry
  • Indole Alkaloids / pharmacology*
  • Interleukin-1beta / pharmacology
  • Intramolecular Oxidoreductases / genetics
  • Intramolecular Oxidoreductases / metabolism
  • Molecular Structure
  • Neuroblastoma / genetics
  • Neuroblastoma / metabolism
  • Neuroblastoma / pathology
  • Phosphorylation / drug effects
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology
  • Prostaglandin-E Synthases
  • Quinolines / chemical synthesis
  • Quinolines / chemistry
  • Quinolines / pharmacology*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / drug effects
  • Transcription Factor RelA / metabolism*
  • p38 Mitogen-Activated Protein Kinases / metabolism*


  • Anti-Inflammatory Agents
  • Cytokines
  • Indole Alkaloids
  • Interleukin-1beta
  • Plant Extracts
  • Quinolines
  • Transcription Factor RelA
  • cryptolepine
  • Cyclooxygenase 2
  • PTGS2 protein, human
  • p38 Mitogen-Activated Protein Kinases
  • Intramolecular Oxidoreductases
  • PTGES protein, human
  • Prostaglandin-E Synthases
  • Dinoprostone