title: Synergistic chondroprotective effects of curcumin and resveratrol in human articular chondrocytes: inhibition of IL-1beta-induced NF-kappaB-mediated inflammation and apoptosis.
abstract: BACKGROUND
  Currently available treatments for osteoarthritis (OA) are restricted to nonsteroidal anti-inflammatory drugs, which exhibit numerous side effects and are only temporarily effective. Thus novel, safe and more efficacious anti-inflammatory agents are needed for OA. Naturally occurring polyphenolic compounds, such as curcumin and resveratrol, are potent agents for modulating inflammation. Both compounds mediate their effects by targeting the NF-kappaB signalling pathway.
  
  
  METHODS
  We have recently demonstrated that in chondrocytes resveratrol modulates the NF-kappaB pathway by inhibiting the proteasome, while curcumin modulates the activation of NF-kappaB by inhibiting upstream kinases (Akt). However, the combinational effects of these compounds in chondrocytes has not been studied and/or compared with their individual effects. The aim of this study was to investigate the potential synergistic effects of curcumin and resveratrol on IL-1beta-stimulated human chondrocytes in vitro using immunoblotting and electron microscopy.
  
  
  RESULTS
  Treatment with curcumin and resveratrol suppressed NF-kappaB-regulated gene products involved in inflammation (cyclooxygenase-2, matrix metalloproteinase (MMP)-3, MMP-9, vascular endothelial growth factor), inhibited apoptosis (Bcl-2, Bcl-xL, and TNF-alpha receptor-associated factor 1) and prevented activation of caspase-3. IL-1beta-induced NF-kappaB activation was suppressed directly by cocktails of curcumin and resveratrol through inhibition of Ikappakappa and proteasome activation, inhibition of IkappaBalpha phosphorylation and degradation, and inhibition of nuclear translocation of NF-kappaB. The modulatory effects of curcumin and resveratrol on IL-1beta-induced expression of cartilage specific matrix and proinflammatory enzymes were mediated in part by the cartilage-specific transcription factor Sox-9.
  
  
  CONCLUSIONS
  We propose that combining these natural compounds may be a useful strategy in OA therapy as compared with separate treatment with each individual compound.
authors.affiliation: Musculoskeletal Research Group, Institute of Anatomy, Ludwig-Maximilians-University Munich, Pettenkoferstrasse 11, 80336 Munich, Germany. constanze.csaki@med.uni-muenchen.de
authors.forename: Constanze
authors.initials: C
authors.lastname: Csaki
authors.forename: Ali
authors.initials: A
authors.lastname: Mobasheri
authors.forename: Mehdi
authors.initials: M
authors.lastname: Shakibaei
mesh_terms: D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D003474:Curcumin / Q000494:pharmacology*; D004357:Drug Synergism; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000378:metabolism; D053583:Interleukin-1beta / Q000187:drug effects; D046529:Microscopy, Electron, Transmission; D016328:NF-kappa B / Q000187:drug effects; D000077185:Resveratrol; D015398:Signal Transduction / Q000187:drug effects; D013267:Stilbenes / Q000494:pharmacology*
chemical_list: D000893:Anti-Inflammatory Agents; D053583:Interleukin-1beta; D016328:NF-kappa B; D013267:Stilbenes; D003474:Curcumin; D000077185:Resveratrol