essential oil reduced acetic acid-induced rat colitis through suppression of NF-κB pathway.

OBJECTIVE

The aim of this study was to evaluate the anti-inflammatory effect of essential oil on colonic inflammation and the role of suppression of NF-κB pathway in rat colitis induced by acetic acid solution.

MATERIALS AND METHODS

Induction of acute colitis was done by intra-luminal instillation of 2 ml of acetic acid (4%) diluted in normal saline. Two hours after colitis induction, 0.2% tween 80 in normal saline, prednisolone (4 mg/kg) or essential oil (100, 200, and 400 mg/kg) were administered to the rats orally and continued for 5 consecutive days. The severity of macroscopic and microscopic damages was assessed. Myeloperoxidase and TNF-α activity was evaluated by biochemical analysis and ELISA respectively and protein expression of p-NF-κB was assessed by immunohistochemistry (IHC).

RESULTS

Prednisolone and essential oil (100, 200, and 400 mg/kg) decreased macroscopic and microscopic injuries compared to the acetic acid group. On the other hand, prednisolone and essential oil (200 and 400 mg/kg) decreased the activity of MPO and TNF-α in the colon tissue of rats compared with the acetic acid group. Furthermore, they suppressed the expression of p-NF-κB protein induced by acetic acid administration.

CONCLUSION

It is suggested that the anti-inflammatory effect of essential oil on acetic acid-induced colitis in rats may be due to the suppression of NF-κB pathway.