Citral, a component of lemongrass oil, activates PPARα and γ and suppresses COX-2 expression

Biochim Biophys Acta. 2010 Nov;1801(11):1214-20. doi: 10.1016/j.bbalip.2010.07.004. Epub 2010 Jul 23.

Abstract

Lemongrass is a widely used herb as a food flavoring, as a perfume, and for its analgesic and anti-inflammatory purposes; however, the molecular mechanisms of these effects have not been elucidated. Previously, we identified carvacrol from the essential oil of thyme as a suppressor of cyclooxygenase (COX)-2, a key enzyme for prostaglandin synthesis, and also an activator of peroxisome proliferator-activated receptor (PPAR), a molecular target for "lifestyle-related" diseases. In this study, we evaluated the essential oil of lemongrass using our established assays for COX-2 and PPARs. We found that COX-2 promoter activity was suppressed by lemongrass oil in cell-based transfection assays, and we identified citral as a major component in the suppression of COX-2 expression and as an activator of PPARα and γ. PPARγ-dependent suppression of COX-2 promoter activity was observed in response to citral treatment. In human macrophage-like U937 cells, citral suppressed both LPS-induced COX-2 mRNA and protein expression, dose-dependently. Moreover, citral induced the mRNA expression of the PPARα-responsive carnitine palmitoyltransferase 1 gene and the PPARγ-responsive fatty acid binding protein 4 gene, suggesting that citral activates PPARα and γ, and regulates COX-2 expression. These results are important for understanding the anti-inflammatory and anti-lifestyle-related disease properties of lemongrass.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acyclic Monoterpenes
  • Animals
  • Cattle
  • Cell Line
  • Cyclooxygenase 2 / biosynthesis*
  • Cyclooxygenase Inhibitors / pharmacology*
  • Humans
  • Ligands
  • Models, Chemical
  • Monoterpenes / pharmacology*
  • PPAR alpha / metabolism*
  • PPAR gamma / metabolism*
  • Plant Oils / chemistry*
  • Promoter Regions, Genetic
  • RNA, Messenger / metabolism
  • Terpenes / chemistry*
  • U937 Cells

Substances

  • Acyclic Monoterpenes
  • Cyclooxygenase Inhibitors
  • Ligands
  • Monoterpenes
  • PPAR alpha
  • PPAR gamma
  • Plant Oils
  • RNA, Messenger
  • Terpenes
  • lemongrass oil
  • Cyclooxygenase 2
  • citral