Cinnamaldehyde is an effective anti-inflammatory agent for treatment of allergic rhinitis in a rat model.

Objectives: The effect of cinnamaldehyde on the treatment of allergic rhinitis (AR) was investigated in rat model.

Methods: Twenty-eight female Wistar albino rats were randomly divided into four groups: Group 1 (control) (C), Group 2 (AR with no treatment) (AR+NoTr), Group 3 (AR+Azelastine HCl) (AR+Aze), and Group 4 (AR+cinnamaldehyde) (AR+Cin). At day 21, AR+Aze rats were given an Azelastine HCl drop, and AR+Cin rats were given cinnamaldehyde intranasally. In all groups, allergic symptoms histopathological results were evaluated.

Results: The AR+NoTr group showed the worst allergic symptoms, cilia loss and greater inflammation. In the AR+Aze and AR+Cin groups, allergic symptom scores were higher than those in the control group. However, between AR+Aze and AR+Cin groups, there were no significant differences in the allergic symptom scores Histopathological analysis revealed vascular congestion and an increase in goblet cell numbers in the AR+Cin group. However, AR+Cin rat nasal mucosa had less plasma cell infiltration compared with the AR+NoTr group. In rats from the AR+Aze group, analysis of the nasal mucosa revealed less eosinophil infiltration than that seen in the AR+NoTr group. A lower score for mast cell (MC) infiltration was observed in the nasal mucosa of rats treated with Azelastine HCl compared with cinnamaldehyde.

Conclusions: In this study we observed that both Azelastine HCl and cinnamaldehyde reduced allergic symptoms in an AR rat model. Cinnamaldehyde decreased vascular congestion as well as plasma cell, eosinophil, and inflammatory cell infiltration into the lamina propria.