Therapeutic effect of Hosta plantaginea (Lam.) Aschers flowers on acute pharyngitis through inhibition of multi-inflammatory pathways in rats

Hosta plantaginea (Lam.) Aschers flower is a famous Mongolian folk medicine in China and has a therapeutic effect on acute pharyngitis (AP). However, the effect and potential mechanism of H. plantaginea flower on AP have not been fully elucidated. The present work aimed to evaluate the effects and mechanisms of the crude extract of H. plantaginea flowers (HP) and its four fractions of petroleum ether fraction (HPA), ethyl acetate fraction (HPB), n-butanol fraction (HPC), and water residue (HPD) against AP in rats. A 15% ammonia-induced AP rat model in rats was established. Therapeutic effects of HP and HPA∼D in model rats were evaluated based on body weight, histopathological analysis, and inflammatory parameters, including tumor necrosis factor α (TNF-α), prostaglandin E2 (PGE2), interleukin 1β (IL-1β), and IL-6. The protein expression of nuclear factor kappa-B p65 (NF-κB p65), inhibitor of NF-κB alpha (IκBα), c-Jun N-terminal kinases (JNK), mitogen-activated protein kinase (MAPK) p38, extracellular signal-regulated kinase (Erk), just another kinase 1 (JAK1), signal transducer and activator of transcription 3 (STAT3), phosphoinositide 3-kinase (PI3K), and protein kinase B (Akt) were detected by a Western blotting assay. HP, HPB, and HPC treatments markedly alleviated AP in rats by increasing body weight and improving pathological damages in pharyngeal tissues. In addition, HP, HPB, and HPC treatments significantly inhibited inflammation, including decreasing the levels of TNF-α, PGE2, IL-1β, and IL-6, and suppressing phosphorylated protein expression of p65, IκBα, JNK, p38, Erk, JAK1, STAT3, PI3K, and Akt in pharyngeal tissues of rats. Collectively, HP, HPB, and HPC can attenuate pharynx injury in rats by suppressing inflammation via inhibition of NF-κB, MAPKs, JAK-STAT, and PI3K-Akt pathways, which supports the traditional use of H. plantaginea flowers.