Protective effect of ginger volatile oil against acetic acid-induced colitis in rats: a light microscopic evaluation

Abstract

Ulcerative colitis is a chronically recurrent inflammatory bowel disease of unknown origin. In the present study, the effect of ginger (rhizome of Zingiber officinale Roscoe) volatile oil on a rat model of colitis was evaluated. Volatile oil of ginger with doses of 100, 200, and 400 mg/kg, prednisolone (4 mg/kg), or vehicle were administered orally to groups of male Wistar rats (n = 6) for 5 d. Animals were randomly divided into 6 groups, each group consisting of 6 rats. Colitis was induced by intracolonic instillation of 2 mL of 4% (v/v) acetic acid solution. All rats were sacrificed 24 h later and the tissue injuries were assessed macroscopically and histopathologically. Ginger volatile oil with all doses reduced colon weight/length ratio (P < 0.01) and the effects were similar to the reference drugs. Higher oral doses of volatile oil (200 and 400 mg/kg) reduced ulcer severity (P < 0.05 and P < 0.01), ulcer area (P < 0.01) and ulcer index (P < 0.01). On the other hand, evaluation of microscopic scores showed that the dose of 400 mg/kg of volatile oil was effective to reduce inflammation severity (P < 0.01) and inflammation extent (P < 0.05) compared to the control group. It is concluded that ginger volatile oil could effectively reduce symptoms of experimental colitis in a dose-dependent manner.