Effects of aqueous extract of Allium cepa (red onion) on ovalbumininduced allergic asthma in wistar rats

Abstract

Asthma is a chronic inflammatory disease of airways that involves inflammatory cells and mediators to elicit inflammatory response. Allium cepa is a common plant used as condiment and has anti–inflammatory, antifungal and antibacterial properties. The aim of this study was to investigate the effect of aqueous extract of Allium cepa (EAC) on leucocytes infiltration and lung histology in Ovalbumin-induced allergic asthma in Wistar rats. Allergic asthma was induced in rats by systemic sensitization with ovalbumin (OVA) via intraperitoneal (i.p.) injections followed by intranasal (i.n.) challenge. Extract of Allium cepa at doses of 150mg/kg and 300mg/kg b.w. ; and dexamethasone (1mg/kg) were given to the treated groups. The asthmatic group showed a significant (p<0.05) increase in number of eosinophil and lymphocyte in the Blood and bronchoalveolar fluid (BALF), which was  significantly (p<0.05) decreased in Allium cepa treated groups. Histological assessment of the lung tissue showed various degrees of inflammation in all OVA-induced animals, but a decreased inflammation was observed in those treated with Allium cepa and dexamethasone. It is therefore, concluded that aqueous extract of Allium cepa reduced cellular infiltration and lung inflammation of allergic asthmatic Wistar rats.

Key words: Asthma, Ovalbumin, Allium cepa, Leucocytes, Rat