Rosmarinic acid suppresses the progression of COPD <i>via</i> Syk by modulating airway inflammation and epithelial apoptosis <i>in vivo</i> and <i>in vitro</i>

Rosmarinic acid (RosA), a hydrophilic phenolic compound found in various plants, has several biological effects such as anti-inflammatory and anti-apoptosis activities. However, its potential impact on chronic obstructive pulmonary disease (COPD) and its underlying mechanism has not been investigated. In this study, we explored the potential therapeutic effects and mechanism of RosA on COPD airway inflammation and alveolar epithelial apoptosis <i>in vivo</i> and <i>in vitro</i>. Our data suggested that RosA may be a therapeutic candidate for COPD with low toxicity. The corresponding mechanism lies in its anti-inflammatory effect on macrophage and bronchial epithelial cells, as well as protective effect on lung epithelial apoptosis via the jointly cross-target spleen tyrosine kinase (Syk).