Terpinen-4-ol, the main component of the essential oil of Melaleuca alternifolia (tea tree oil), suppresses inflammatory mediator production by activated human monocytes

Inflamm Res. 2000 Nov;49(11):619-26. doi: 10.1007/s000110050639.


Objective and design: To evaluate potential antiinflammatory properties of tea tree oil, the essential oil steam distilled from the Australian native plant, Melaleuca alternifolia.

Material and methods: The ability of tea tree oil to reduce the production in vitro of tumour necrosis factor-alpha (TNFalpha), interleukin (IL)-1beta, IL-8, IL-10 and prostaglandin E2 (PGE2) by lipopolysaccharide (LPS)-activated human peripheral blood monocytes was examined.

Results: Tea tree oil emulsified by sonication in a glass tube into culture medium containing 10% fetal calf serum (FCS) was toxic for monocytes at a concentration of 0.016% v/v. However, the water soluble components of tea tree oil at concentrations equivalent to 0.125% significantly suppressed LPS-induced production of TNFalpha, IL-1beta and IL-10 (by approximately 50%) and PGE2 (by approximately 30%) after 40 h. Gas chromatography/mass spectrometry identified terpinen-4-ol (42 %), a-terpineol (3 %) and 1,8-cineole (2%, respectively, of tea tree oil) as the water soluble components of tea tree oil. When these components were examined individually, only terpinen-4-ol suppressed the production after 40 h of TNFalpha, IL-1beta, IL-8, IL-10 and PGE2 by LPS-activated monocytes.

Conclusion: The water-soluble components of tea tree oil can suppress pro-inflammatory mediator production by activated human monocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology*
  • Cyclohexane Monoterpenes
  • Cyclohexanols*
  • Cyclohexenes
  • Cytokines / biosynthesis*
  • Emulsions / pharmacology
  • Eucalyptol
  • Humans
  • Interleukin-1 / biosynthesis
  • Lipopolysaccharides / pharmacology
  • Macrophages / drug effects
  • Macrophages / immunology
  • Menthol / analogs & derivatives*
  • Menthol / pharmacology
  • Monocytes / drug effects
  • Monocytes / immunology*
  • Monoterpenes*
  • Plants, Medicinal*
  • Solubility
  • Tea Tree Oil / chemistry
  • Tea Tree Oil / pharmacology*
  • Terpenes / pharmacology*
  • Tumor Necrosis Factor-alpha / biosynthesis


  • Anti-Inflammatory Agents, Non-Steroidal
  • Cyclohexane Monoterpenes
  • Cyclohexanols
  • Cyclohexenes
  • Cytokines
  • Emulsions
  • Interleukin-1
  • Lipopolysaccharides
  • Monoterpenes
  • Terpenes
  • Tumor Necrosis Factor-alpha
  • Menthol
  • alpha-terpineol
  • terpinenol-4
  • Tea Tree Oil
  • Eucalyptol