title: In vitro biological evaluation of eight different essential oils against Trypanosoma cruzi, with emphasis on Cinnamomum verum essential oil.
abstract: BACKGROUND
  Essential oils (EOs) are complex mixtures of secondary metabolites from various plants. It has been shown that several EOs, or their constituents, have inhibitory activity against trypanosomatid protozoa. Thus, we analyzed the biological activity of different EOs on Trypanosoma cruzi, as well as their cytotoxicity on Vero cells.
  
  
  METHODS
  The following EOs were evaluated on T. cruzi epimastigote forms: Cinnamomum verum, Citrus limon, Cymbopogon nardus, Corymbia citriodora, Eucalyptus globulus, Eugenia uniflora, Myrocarpus frondosus, and Rosmarinus officinalis. Inhibitory activity against T. cruzi (IC50/24 h) and cytotoxicity against Vero cells (CC50/24 h) were evaluated by the MTT assay. The EO of C. verum was selected for further evaluation against trypomastigotes and intracellular amastigotes, as well as on parasite metacyclogenesis. Constituents of C. verum EO were identified by GC-MS. One-way ANOVA statistical analysis was performed with GraphPad version 5.01.
  
  
  RESULTS
  Cinnamomum verum EO was the most effective against T. cruzi epimastigotes (IC50/24 h = 24.13 μg/ml), followed by Myrocarpus frondosus (IC50/24 h = 60.87 μg/ml) and Eugenia uniflora (IC50/24 h = 70 μg/ml). The EOs of C. citriodora, E. globulus, and R. officinalis showed no activity at concentrations up to 300 μg/ml. Incubation of T. cruzi metacyclic trypomastigotes and intracellular amastigotes with C. verum EO resulted in IC50/24 h values of 5.05 μg/ml and 20 μg/ml, respectively. Therefore, trypomastigotes are more susceptible than epimastigotes, with selectivity index (SI) about 4.7-fold higher (9.78 and 2.05, respectively). Analysis of C. verum EO by GC-MS showed mainly (E)-cinnamaldehyde (81.52%) and eugenol (16.68%).
  
  
  CONCLUSIONS
  C. verum essential oil is effective against T. cruzi (epimastigotes, trypomastigotes and amastigotes) and interferes with the parasite differentiation process in vitro. Thus, it represents a strong candidate for further studies to improve its activity on pathogenic trypanosomatids.
authors.forename: Camila Maria O
authors.initials: CM
authors.lastname: Azeredo
authors.forename: Thalita Gilda
authors.initials: TG
authors.lastname: Santos
authors.forename: Beatriz Helena Lameiro de Noronha Sales
authors.initials: BH
authors.lastname: Maia
authors.affiliation: Laboratory of Cell Biology, Carlos Chagas Institute/Fiocruz, Rua Prof, Algacyr Munhoz Mader 3775, Cidade Industrial, 81350-010 Curitiba, PR, Brazil. maurilio@tecpar.br.
authors.forename: Maurilio José
authors.initials: MJ
authors.lastname: Soares
mesh_terms: D000981:Antiprotozoal Agents / Q000494:pharmacology*; D014355:Chagas Disease / Q000469:parasitology; D027424:Cinnamomum / Q000737:chemistry*; D031743:Cymbopogon / Q000737:chemistry; D004353:Drug Evaluation, Preclinical; D005052:Eucalyptus / Q000737:chemistry; D005054:Eugenol / Q000494:pharmacology; D006801:Humans; D009822:Oils, Volatile / Q000494:pharmacology*; D010938:Plant Oils / Q000494:pharmacology*; D027842:Syzygium / Q000737:chemistry; D014349:Trypanosoma cruzi / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000981:Antiprotozoal Agents; D009822:Oils, Volatile; D010938:Plant Oils; D005054:Eugenol