The Extract of <i>Rosa roxburghii</i> Tratt Alleviates Pulmonary Fibrosis in Mice via Gut Microbiota‐Amino Acid Metabolism and <scp>JAK2</scp> / <scp>STAT3</scp> Inhibition

Tratt (RRT), which has anti-inflammatory and antioxidant properties, exhibits the potential to attenuate organ fibrosis. In this study, we evaluated the bioactive content and antioxidant capacity of different polar extracts of RRT (RRTEs), and explored the multi-target mechanism of the optimal extract in alleviating PF. The ethyl acetate extract of RRT (EAE) exhibited the highest bioactive content and the strongest antioxidant capacity. EAE intervention reshaped the gut microbiota composition in PF mice by enriching beneficial bacteria and reducing pathogenic taxa. Metabolomic analysis identified 11 potential serum biomarkers associated with PF, which were involved in 7 metabolic pathways. Notably, EAE attenuated the disruption of L-tryptophan metabolism, primarily through modulation of serotonin. Moreover, EAE was found to alleviate epithelial-mesenchymal transition (EMT) and inhibit inflammatory cytokine via the JAK2/STAT3 pathway. In conclusion, EAE may exert anti-PF effects associated with the structure of the gut microbiota, correction of amino acid metabolic disorders (notably tryptophan metabolism) and modulating JAK2/STAT3 signaling pathway in the lung. These findings provide new insights into the therapeutic potential of EAE against PF.