Abstract
Acute respiratory distress syndrome is a high mortality clinical disorder characterized by lung inflammation. Several monoterpenes from essential oils have an anti-inflammatory activity. The tymol and carvacrol show hydroxyl at C-3 and C-2 positions, respectively, in their chemical structures while in p-cimene, the hydroxyl group is not present. We evaluated the effects of these natural compounds in a model of acute lung injury (ALI). Mice received intratracheal LPS or saline and were evaluated after 6 or 24hs to determine if lung inflammation is already present after 6hs. Then, mice were treated with tymol, carvacrol, p-cimene, dexametasone or vehicle 6hs after the LPS or saline intratracheal instillation. Lung inflammation and mechanics were evaluated after 24 hours. Animals presented an increase in neutrophils and lymphocytes in BALF 6hs after LPS, that was persistent for 24 hs (P<0.05 compared to saline group). We evaluated three different doses of the compounds and 20mg/Kg was more effective to reducing total and neutrophils cells in BALF of LPS. Comparing the effect of the dose of 20mg/Kg of the three compounds, we have found that all of them were able to reduce significantly total cells, neutrophils and lymphocytes in BALF and to reduce airway respiratory resistance and elastance as well as tissue elastance compared to LPS and vehicle treated animals (P<0.05). In conclusion, tymol, carvacrol and p-cimene reduce lung inflammation and improve lung function in a murine ALI model. The presence or the position of hydroxyl does not seem to be important to counteract lung inflammation in ALI model. The mechanisms of action needs to be investigated. Supported by FAPESP/CNPq/CAPES.
- © 2014 ERS