Anti-Allergic and Anti-inflammatory Effects of Bakuchiol on Ovalbumin-Induced Allergic Rhinitis in Mice

Allergic rhinitis (AR) is a prevalent inflammatory disease primarily affecting the nasal mucosa and is caused by allergies. The common symptoms of AR include rhinorrhea, sneezing, itchy nose, congestion, teary eyes, and nasal rubbings. The present study assessed the beneficial properties of bakuchiol on OVA-induced AR in mice via the regulation of inflammatory responses. AR was induced by injecting (i.p.) OVA (50 µg) and aluminum hydroxide (1 mg) into mice at various time intervals. The bakuchiol treatment was done at dosages of 10 and 20 mg/kg with dexamethasone (2.5 mg/kg) as a positive control. The body weight and nasal symptoms were measured on the day of the last OVA challenge. For in vitro tests, mouse splenocytes were isolated, sensitized with 20 µL OVA, and then treated with 10 µM bakuchiol. The levels of pro-inflammatory cytokines, immunoglobulins, histamine, leukotriene C4 (LTC-4), and prostaglandin D2 (PGD2) were assayed using the corresponding assay kits. The assay kits were also used to analyze the status of oxidative stress markers. The Th1/Th2 cell proportion was assessed using flow cytometry. The bakuchiol (10 and 20 mg/kg) treatment reduced the nasal symptoms in AR mice. Bakuchiol decreased the levels of IL-4, IL-5, IL-13, Igs (IgE and IgG1), histamine, IL-10, IL-33, and TNF-α in AR mice. Bakuchiol also reduced PGDA and LTC-4 levels in the NLF of AR mice. The ROS and MDA levels were decreased, whereas boosted SOD activity was observed in the bakuchiol-treated AR mice. The eosinophil count was decreased in the nasal tissues of bakuchiol-treated AR mice. Bakuchiol also influenced the Th1 and Th2 cell proportions in AR mice. The present findings suggest that bakuchiol is effective against OVA-mediated allergic and inflammatory responses in AR mice through its strong anti-inflammatory properties.

Allergic response; Bakuchiol; Eosinophils; Sneezing; Th2 cytokines.