The lungs are the internal organ that is most highly exposed to various environmental threats. Therefore, it has evolved the ability to confront oxidative stress induced by reactive oxygen species (ROS) and various stimuli, including pollutants, pathogens, and allergens, which can harm the airways and induce inflammation. Increasing evidence indicates a possible causal link among inflammation, ROS imbalance, and pulmonary disorders, such as asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and acute respiratory distress syndrome. Therefore, most of these diseases are treated with anti-inflammatory therapy to prevent or reduce pulmonary inflammation.

The natural products derived from plants and animals have been used in folk medicine and scientific studies to evaluate the value of these compounds, which have grown in recent years. Many substances derived from plants, such as flavonoids, alkaloids, and terpenoids, have various biological effects in vitro and in vivo due to their polyhydroxy structures. Among the biological activities of natural products derived from plants, the anti-inflammatory, antiviral, antiplatelet, antitumor, anti-allergic, and antioxidant activities as well as immunomodulatory effects can be pointed out, and the substances with different chemical structures have different biological activities. These properties could have the potential for the prevention and treatment of pulmonary inflammatory diseases. Although many reports have evaluated the effects of these compounds in experimental models, studies evaluating structure-activity relationships, toxicity, and therapeutic potential in clinical trials are scarce.

This Special Issue aims to collate the protective effects of natural products against various inflammatory pulmonary diseases including asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and acute lung injury in experimental models and in humans, pointing out possible mechanisms of action. We welcome both original research and review articles.

Potential topics include but are not limited to the following:

• The role of natural products on various stimuli-induced activation of alveolar macrophages, neutrophils, and platelets in the development of lung inflammation
• The impact of natural products on lung microbiota homeostasis to shape lung inflammation and infection
• Novel anti-inflammatory compounds derived from the herbal medicine
• The structure-activity relationships of flavonoids and terpenoids on airway inflammation
• The role of natural products against airway inflammation by regulating immune resistance
• Synergistic effects of bioactive compounds on airway inflammation
• Prospects and paradigms of natural products on airway inflammation
• The clinical investigation of natural products against asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and acute respiratory distress syndrome
• The transcriptomics, proteomics, and metabolomics to reveal the therapeutic mechanism underlying herbal medicine for the treatment of pulmonary diseases
• Plant-derived nanomaterials for the prevention of airway inflammation
• The high-content image-based assay for identifying novel anti-inflammatory compounds in herbal medicine
• Preparation, structure, and activity of natural products by structural modification for airway inflammation therapy