Effects of Rourea coccinea ethanolic root extract on ovalbumin-induced allergic astma in rats

Abstract

Rourea coccinea (syn. Byrsocarpus coccineus) Schum. and Thonn. (Connaraceae) is a medicinal plant that is being used for the treatment of various disorders in Tropical Africa. Previously, we reported anti-inflammatory and antioxidant effects of ethanolic extract of R. coccinea root bark (EERc). The present study aimed to test protective potential effects of EERc treatments against ovalbumin-induced airway lung inflammatory and to investigate some of its possible underlying mechanism on allergic asthma. Rats were sensitized and challenged with ovalbumin (OVA), and were orally treated daily with EERc at 200, 400 and 800 mg/kg from day 24 to day 27 post sensitization. The number of total and differential inflammatory cells, leakage of Evans blue dye tracer, histamine and TNF-α level in bronchoalveolar lavage (BAL) fluid were measured. OVA instillation induced airway lung inflammation, which was significantly suppressed by pre-treatment with EERc. Analysis of bronchoalveolar lavage (BAL) revealed that EERc pre-treatment significantly inhibited leukocytosis and reduced Evans blue dye content in the BAL fluid. EERc also significantly decreased the production and release of histamine and TNF-α. Our study shows that EERc possesses significant anti-allergic activity which might be attributed to reduction of histamine, TNF-α in the BAL fluid.