Quercetin Attenuates Acute Lung Injury Caused by Cigarette Smoke Both In Vitro and In Vivo.

Cigarette smoke is highly toxic and is a major risk factor for airway inflammation, oxidative stress, and decline in lung function-the starting points for chronic obstructive pulmonary disease. Quercetin is a potent dietary antioxidant that displays anti-inflammatory activities. The goal of this study was to evaluate the effects of quercetin on reducing the redox imbalance and inflammation induced by short-term cigarette smoke exposure. In vitro, 25 and 50 μM quercetin attenuated the effects of cigarette smoke extract (increased generation of reactive oxygen species and nitric oxide) on J774A.1 cells (macrophages). We further examined the effects of quercetin in vivo. Male C57Bl/6 mice that received 10 mg/kg/day of quercetin via orogastric gavage before exposure to five days of cigarette smoke demonstrated reduced levels of leukocyte, oxidative stress, histological pattern changes of pulmonary parenchyma, and lung function alterations compared to the group that did not receive quercetin. These results suggest that quercetin may be an effective adjuvant for treating the effects of cigarette smoke exposure.