Protective effect of eucalyptus oil on pulmonary destruction and inflammation in chronic obstructive pulmonary disease (COPD) in rats

Abstract

Eucalyptus oil (EO), an essential oil isolated from Eucalyptus leaves, was examined for its effect on lipopolysaccharide (LPS) and Klebsiella pneumoniae-induced COPD in rats. The COPD model was induced by instilling intratracheally with LPS and K. pneumoniae. The test compound, EO (30, 100 and 300 mg/kg), prednisone acetate (10 mg/kg) or vehicle was instilled intragastrically after three weeks exposure to LPS and K. pneumoniae, lasting for 4 weeks. EO significantly reduced amounts of inflammatory cells in bronchoalveolar lavage fluid (BALF) and blood, and decreased bronchiolitis, emphysematous changes and thickness of bronchioles. It also significantly reduced the increased AB-PAS-positive goblet cells in bronchioles. Prednisone acetate attenuated pulmonary inflammation and airway mucus hypersecretion, but no significant difference was found on emphysema. Pretreatment with EO markly reduced the production of proinflammatory cytokines TNF-α and IL-β in lung homogenate, significantly decreased the elevated malondialdehyde (MDA) level and and increased superoxide dismutase (SOD) activity. These findings indicate that EO could exert an protective effect against LPS plus K. pneumoniae-induced lung indury via inhibition of proinflammatory cytokines production and improvement of anti-oxidant status. The results provide evidence that EO might have its potential to be a proper candidate drug in the treatment of COPD. Key words: Eucalyptus globulus, lipopolysaccharide, cytokine, chronic obstructive pulmonary disease.