In vitro and in vivo action of terpinen-4-ol, γ-terpinene, and α-terpinene against Trypanosoma evansi

Exp Parasitol. 2016 Mar;162:43-8. doi: 10.1016/j.exppara.2016.01.004. Epub 2016 Jan 8.


This study aimed to evaluate the susceptibility in vitro and in vivo of Trypanosoma evansi to terpinen-4-ol, γ-terpinene and α-terpinene, the three main compounds of tea tree oil (Melaleuca alternifolia) with known efficacy in the treatment of trypanosomosis. In vitro, a trypanocidal effect of terpinen-4-ol, γ-terpinene, and α-terpinene was observed when used alone or associated at 0.5, 1 and 2% concentrations i.e., the α-terpinene showed a faster trypanocidal effect when compared to chemotherapy (diminazene aceturate - D.A.). In vivo studies were performed in two experiments: I and II where experiment I used T. evansi infected mice treated with terpinen-4-ol, γ-terpinene and α-terpinene alone (at a dose of 1.0 mL kg(-1)) or associated (two compounds, dose of 0.5 mL kg(-1) of each compound; tree compounds, dose of 0.335 mL kg(-1) of each compound); Treatment with α-terpinene was able to extend animal longevity, but showed no curative efficacy. In experiment II, T. evansi infected mice were treated with D.A. associate with α-terpinene, where a curative efficacy of 57.14% was found, a much better result when D.A. was used alone (14.28%). In summary, α-terpinene associated with D.A. can be used as an alternative treatment for T. evansi infection. The compound α-terpinene from M. alternifolia essential oil is the one responsible for the trypanocidal effect, a fact confirmed by in vitro results and the increased longevity observed on treated mice.

Keywords: Majority compounds; TTO; Trypanosomosis; α-terpinene.

MeSH terms

  • Animals
  • Cyclohexane Monoterpenes
  • Diminazene / analogs & derivatives
  • Diminazene / pharmacology
  • Diminazene / therapeutic use
  • Dogs
  • Dose-Response Relationship, Drug
  • Female
  • Mice
  • Monoterpenes / pharmacology*
  • Monoterpenes / therapeutic use
  • Rats
  • Terpenes / pharmacology*
  • Terpenes / therapeutic use
  • Trypanocidal Agents / pharmacology*
  • Trypanocidal Agents / therapeutic use
  • Trypanosoma / drug effects*
  • Trypanosomiasis / drug therapy*
  • Trypanosomiasis / parasitology


  • Cyclohexane Monoterpenes
  • Monoterpenes
  • Terpenes
  • Trypanocidal Agents
  • gamma-terpinene
  • terpinenol-4
  • diminazene aceturate
  • Diminazene