Rehder & E.H.Wilson. Bark Extract and Magnolol Alleviate Allergic Rhinitis via Modulating NF-κB/MAPK Signaling.

Abstract

Rehder & E.H.Wilson. bark is famous as a traditional herbal medicine used in prescriptions for treating gastrointestinal discomfort, respiratory and inflammatory disorders. Magnolol, one of its principal bioactive constituents, exhibits potent anti-inflammatory and immunomodulatory properties. However, its therapeutic mechanisms in allergic rhinitis (AR) remain to be elucidated. In this study, the anti-allergic effects and molecular mechanisms of.bark aqueous extract (MOAE) and magnolol were investigated using an ovalbumin (OVA)-induced AR mouse model. Nasal symptoms, histopathological alterations, and serum inflammatory mediators, including histamine and immunoglobulins (IgE, IgG1, IgG2a), were evaluated to assess efficacy. Both MOAE and magnolol significantly alleviated nasal rubbing and sneezing, reduced eosinophil infiltration and mucus hypersecretion, and improved tissue morphology in nasal and lung sections. Moreover, treatment markedly decreased serum levels of histamine and OVA-specific antibodies. Integrative network pharmacology, RNA sequencing, and molecular docking analyses revealed 33 co-regulated target genes mainly involved in the NF-κB and MAPK signaling pathways, suggesting that modulation of these pathways underlies the observed anti-inflammatory effects. These findings demonstrate that MOAE and magnolol exert protective effects against AR through the regulation of key inflammatory signaling cascades. This study provides modern pharmacological evidence supporting the traditional use ofbark and highlights its potential as a natural therapeutic candidate for AR.