Capsicum annuum L. methanolic extract inhibits ovalbumin-induced airway inflammation and oxidative stress in a mouse model of asthma.

The pepper fruit of Capsicum annuum L. is used as a food, spice, and topical medicine. Here, we investigated the effect of a methanolic C. annuum L. extract (CAE) in a mouse model of ovalbumin-induced allergic airway inflammation. Animals were treated with CAE by oral gavage before ovalbumin challenge. After ovalbumin challenge, airway responsiveness to methacholine, influx of inflammatory cells into the lung, cytokine levels in bronchoalveolar lavage fluid and lung, nuclear factor-κB (NF-κB) activity in lungs, and lung histopathology were assessed. Oral treatment with CAE significantly reduced the pathophysiological signs of allergic airway disease, including increased inflammatory cell recruitment to the airways, airway hyperresponsiveness, and increased levels of T-helper type 2 cytokines. Reactive oxygen species were also decreased in cells from bronchoalveolar lavage fluid. In addition, we found that administration of CAE attenuated ovalbumin-induced increases in NF-κB activity in lungs. Collectively, these results suggest that CAE may be an effective oral treatment for allergic airway inflammation by virtue of its antioxidant activity.