Total alkaloids in Fritillaria cirrhosa D. Don alleviate OVA-induced allergic asthma by inhibiting M2 macrophage polarization

Ethnopharmacological relevance

Fritillaria cirrhosa D. Don (FCD) is a traditional Chinese medicine used to treat respiratory disorders, known for its effects in clearing heat, moistening the lungs, resolving phlegm, and relieving cough. Additionally, the total alkaloids extracted from FCD can alleviate asthma symptoms and reduce airway inflammation. However, no studies have investigated the effects of total alkaloids on lung macrophages.

Aim of the study

This study explored whether the total alkaloids of FCD (TAs-FCD) reduce M2 macrophage polarization and, consequently, attenuate airway remodeling in asthmatic mice. This study further elucidated its mechanism of action in treating allergic asthma.

Materials and methods

The extracted TAs-FCD was analyzed for its composition using UPLC-Q-TOF/MS. Network pharmacology was employed to identify the active ingredients and potential mechanisms of TAs-FCD in the treatment of allergic asthma. A mouse model of ovalbumin-induced allergic asthma was established, adopted, and validated through in vivo experiments. Hematoxylin-eosin staining (H&E), immunohistochemistry (IHC), immunofluorescence staining (IF), enzyme-linked immunosorbent assay (ELISA), Western blotting (WB), and real-time fluorescence quantitative polymerase chain reaction (q-PCR) were used to investigate the role of TAs-FCD in inhibiting M2 macrophage polarization in the context of allergic asthma.

Results

A total of 66 active ingredients were screened from 116 compounds using SWISSADME. The targets of these 66 compounds were predicted by SwissTargetPrediction, resulting in 808 unique drug targets after excluding duplicates. Additionally, 1756 targets related to allergic asthma were identified from the DisGeNET, Genecard, and OMIM databases. This led to 267 cross-targets between the active ingredient targets and allergic asthma targets, including interleukin (IL)-1β, tumor necrosis factor (TNF), and STAT3. Animal experiments demonstrated that TAs-FCD improved histopathological injury in mouse lungs, reduced peri-airway collagen fiber accumulation, airway mucus secretion, and airway smooth muscle proliferation. TAs-FCD also lowered IL-1β, TNF-α and IL-4 levels in lung tissues and alleviated airway inflammation. Furthermore, TAs-FCD significantly reduced levels of Arg1 and CD206, which are closely associated with M2 macrophages, and downregulated the expression of p-STAT3 and p-JAK2.

Conclusion

TAs-FCD may inhibit M2 macrophage polarization by regulating the JAK2/STAT3 pathway, thereby alleviating airway remodeling and inflammation in allergic asthmatic mice.