Ethnopharmacological Evaluation of Breu Essential Oils from Protium Species Administered by Inhalation

Background Breu is an aromatic oleoresin which has been used by Amazonian traditional communities as a remedy for headaches and migraines by burning and inhaling the smoke produced during its combustion. This study evaluated the antinociceptive and sedative activities of formulations containing breu essential oils administered by inhalation. Methods Five different formulations (A-E) containing breu essential oils were evaluated for their sedative and antinociceptive activities in mice. They were delivered for 20 minutes using an inhalation chamber coupled with a nebulizer and the air inside was collected by static headspace and analyzed by GC-FID. Results All nebulized formulations had similar chemical compositions and major compounds as the original essential oils. None of them resulted in significant increase in response time during the hot plate test. In the formalin test, Formulation E showed a significant inhibition of licking responses in the early (46.8%) and late (60.2%) phases. Formulation B was effective (36.9%) in the first phase and Formulation D (37.9%) in the second. None of the formulations presented sedative effects. Conclusion Breu essential oils, when inhaled, may present antinociceptive and anti-inflammatory properties without sedation. Additionally, nebulization proved to be an efficient method for administration of formulations containing these essential oils.