Juglans regia (J. regia) has been used traditionally to treat cough and asthma. The present study evaluates the immunomodulatory and anti-inflammatory potential of J. regia against ovalbumin (OVA)-induced allergic asthma. Intraperitoneal sensitization proceeded by intranasal challenge with OVA was used to induce allergic asthma. BALB/c mice were treated with methanol, n-hexane, and ethyl acetate extracts of J. regia and methylprednisolone one week after 2nd sensitization with OVA and continued for 7 days. mRNA expression levels of IL-4, IL-5, IL-13, AQP-1, AQP-5 TNF-α, TGF-ß, and NF-kB were determined using reverse transcription polymerase chain reaction. Hematoxylin and eosin, and periodic acidic-Schiff stains were used for histopathological studies of lung tissues. The data presented all three extracts of J. regia significantly ameliorated airway inflammation by reducing expression levels of IL-4, IL-5, and IL-13 and TNF-α in OVA-treated mice. The suppression of goblet cells hyperplasia and inflammatory cells infiltration by J. regia involved low TGF-ß and NF-kB levels. Pretreatment with J. regia also increased the AQP-1 and AQP-5 expression levels in mice treated with OVA. This study supported the traditional use of J. regia and proposed that J. regia ameliorated allergic asthma by suppression of proinflammatory cytokines and elevation of AQP-1 and AQP-5 expression levels.
