Hosta plantaginea flower ameliorates chronic pharyngitis by suppressing inflammation via the JAK‐STAT/PI3K/MAPK signaling axis in rats

Hosta plantaginea flower is an important Chinese herb in treating chronic pharyngitis (CP); however, its pharmacodynamics against CP and the underlying mechanisms remain unclear. This study demonstrated that the ethyl acetate (HPB) and n‐butanol (HPC) fractions of the H. plantaginea flower were identified as the active fractions against CP, significantly increasing the body weight, improving damaged pharyngeal tissues, and reducing TNF‐α, PGE2, IL‐1β, and IL‐6 levels in rats induced by 5% ammonia solution. Metabolomics studies identified 55 differential metabolites, with 26 being reversely regulated by HPB and HPC. These 26 metabolites are closely associated with phosphoinositide 3‐kinase‐protein kinase B (PI3K‐Akt), just another kinase‐signal transducers and activators of transcription (JAK‐STAT), mitogen‐activated protein kinases (MAPKs), and nuclear factor kappa‐B (NF‐κB) pathways. Mechanically, HPB and HPC prominently suppressed the expression of phosphorylated PI3K, Akt1, JAK1, STAT3, JNK, p38, Erk, p65, and inhibitor of NF‐κB (IκBα) proteins. Finally, HPLC analysis identified flavonoids as the primary phytochemicals of HPB and HPC. In conclusion, HPB and HPC are the main active fractions of H. plantaginea flower against CP, acting through regulating energy metabolism and inhibiting PI3K‐Akt, JAK‐STAT, MAPKs, and NF‐κB signaling pathways, and the flavonoids are the primary constituents.