Phaeanthus vietnamensis Ban Ameliorates Lower Airway Inflammation in Experimental Asthmatic Mouse Model via Nrf2/HO-1 and MAPK Signaling Pathway

Asthma is a chronic airway inflammatory disease listed as one of the top global health problems. Phaeanthus vietnamensis BÂN is a well-known medicinal plant in Vietnam with its anti-oxidant, anti-microbial, anti-inflammatory potential, and gastro-protective properties. However, there is no study about P. vietnamensis extract (PVE) on asthma disease. Here, an OVA-induced asthma mouse model was established to evaluate the anti-inflammatory and anti-asthmatic effects and possible mechanisms of PVE. BALB/c mice were sensitized by injecting 50 μg OVA into the peritoneal and challenged by nebulization with 5% OVA. Mice were orally administered various doses of PVE once daily (50, 100, 200 mg/kg) or dexamethasone (Dex; 2.5 mg/kg) or Saline 1 h before the OVA challenge. The cell infiltrated in the bronchoalveolar lavage fluid (BALF) was analyzed; levels of OVA-specific immunoglobulins in serum, cytokines, and transcription factors in the BALF were measured, and lung histopathology was evaluated. PVE, especially PVE 200mg/kg dose, could improve asthma exacerbation by balancing the Th1/Th2 ratio, reducing inflammatory cells in BALF, depressing serum anti-specific OVA IgE, anti-specific OVA IgG1, histamine levels, and retrieving lung histology. Moreover, the PVE treatment group significantly increased the expressions of antioxidant enzymes Nrf2 and HO-1 in the lung tissue and the level of those antioxidant enzymes in the BALF, decreasing the oxidative stress marker MDA level in the BALF, leading to the relieving the activation of MAPK signaling in asthmatic condition. The present study demonstrated that Phaeanthus vietnamensis BÂN, traditionally used in Vietnam as a medicinal plant, may be used as an efficacious agent for treating asthmatic disease.