Oleuropein ameliorates airway inflammation and emphysema in a chronic obstructive pulmonary disease model

Chronic obstructive pulmonary diseases (COPD) such as emphysema and chronic bronchitis are progressive lung diseases characterized by irreversible airflow obstruction and chronic inflammation of the airways, lung tissue and pulmonary blood vessels as a result of exposure to inhaled irritants. The current study investigated that oleuropein, a phenylethanoid found in olive leaves, inhibited eosinophilic airway inflammation evident in COPD in interleukin (IL)‐4‐exposed airway epithelial BEAS‐2B cells and ovalbumin (OVA)‐sensitized mice. Nontoxic oleuropein at 1–20 μM attenuated the induction of eosinophil chemotactic protein eotaxin‐1 and its receptor CCR3 in 50 ng/ml IL‐4 stimulated epithelial cells. The in vivo study explored the demoting effects of oleuropein on allergic inflammation in cigarette smoke/OVA‐exposed BALB/c mice. Mice were exposed to cigarette smoke for 30 min in a smoke chamber. It has been reported that IL‐4 production increased in smoke‐induced COPD and emphysema. Oral supplementation of 20 mg/kg oleuropein reduced the number of eosinophils and neutrophils elevated in bronchoalveolar lavage fluid of cigarette smoke/OVA‐exposed mice. Oral administration of oleuropein suppressed the induction of CD11b(+) and F4/80(+) with congruent small airway destruction in cigarette smoke/OVA‐exposed mice airways and lungs. These results demonstrated that oleuropein inhibited eosinophilia and inexorable emphysema associated with allergic cellular inflammation by cigarette smoke/OVA irritants. Therefore, oleuropein may be a potential agent targeting against chronic inflammation and emphysema in COPD.