Undaria pinnatifida ameliorates nasal inflammation by inhibiting eosinophil and mast cell activation and modulating the NF-κB/MAPKs signaling pathway

Background: Allergic rhinitis (AR) is the most prevalent form of atopic disease. Undaria pinnatifida has potent antioxidative, antidiabetic, and anti-inflammatory properties. Aims: We investigated the immunomodulatory effect of Undaria pinnatifida extract (UPE) on allergic inflammation in an AR mouse model. Materials & Methods: Mice were sensitized and intranasally challenged with ovalbumin (OVA), and the Th1/Th2 and Th17/Treg-related cytokines and histopathology were exanimated after UPE treatments. Enzyme-linked immunosorbent assay was performed using serum samples and NALF to detect OVA-specific immunoglobulins and inflammatory cytokines. Mitogen-activated protein kinases (MAPKs) were measured by western blotting analysis, and an in vitro study measured mast cell activation induced by compound 48/80. Results: After UPE treatment, nasal and lung allergy symptoms, nasal mucosal swelling, and goblet cell hyperplasia were ameliorated. Oral UPE regulated the balance of Th1/Th2 and Th17/Treg cell differentiation in AR mice in a dose-dependent manner. In addition, UPE attenuated the migration of eosinophils and mast cells to the nasal mucosa by suppressing nuclear factor kappa B (NF-κB)/MAPKs. The levels of anti-OVA IgE and IgG₁ were also decreased. Discussion: UPE inhibited inflammation by regulating the NF-κB/MAPKs signaling pathway and supressing the activation of critical immune cells such as eosinophils and mast cells. Conclusion: UPE may have therapeutic potential for AR.