Planta Med 2005; 71(12): 1173-1175
DOI: 10.1055/s-2005-873173
© Georg Thieme Verlag KG Stuttgart · New York

Relaxant Effects of the Essential Oil of Eucalyptus tereticornis and its Main Constituent 1,8-Cineole on Guinea-Pig Tracheal Smooth Muscle

Lívia Noronha Coelho-de-Souza1 , José Henrique Leal-Cardoso2 , Francisco José de Abreu Matos3 , Saad Lahlou4 , Pedro Jorge Caldas Magalhães1
  • 1Departamento de Fisiologia e Farmacologia, Universidade Federal do Ceará, Fortaleza, CE, Brasil
  • 2Instituto Superior de Biomedicina, Universidade Estadual do Ceará, Fortaleza, CE, Brasil
  • 3Laboratório de Produtos Naturais, Centro de Ciências, Universidade Federal do Ceará, Foraleza, CE, Brasil
  • 4Departamento de Fisiologia e Farmacologia, Universidade Federal de Pernambuco, Recife, PE, Brasil
Further Information

Publication History

Received: December 31, 2004

Accepted: June 20, 2005

Publication Date:
10 November 2005 (online)


The effects of the essential oil of Eucalyptus tereticornis Sm. (EOET) on guinea-pig tracheal smooth muscle were investigated. EOET (10 - 1000 μg/mL) relaxed the tracheal basal tonus with an EC50 value of 125.3 [52.2 - 300.9] μg/mL. Its maximal relaxation (40 ± 6 %) was significantly lower than that evoked by aminophylline (209 ± 34 %). The K+-(60 mM)-induced contractions were significantly reduced by both EOET (200 - 1000 μg/mL) and its main constituent 1,8-cineole (600 - 1000 μg/mL). Acetylcholine (1 μM)-induced contractions were significantly enhanced by 1,8-cineole (10 - 1000 μg/mL). However, they were significantly enhanced and reduced by lower (200 - 400 μg/mL) and higher (800 - 1000 μg/mL) concentrations of EOET, respectively. Electrical field stimulation-induced contractions were significantly increased by EOET (100 - 600 μg/mL). In conclusion, EOET produces myorelaxant effects on guinea-pig isolated trachea, an effect that seems to result from a complex interaction between its monoterpenoid constituents.


Prof. Pedro J. C. Magalhães

Departamento de Fisiologia e Farmacologia

Universidade Federal do Ceará

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