Biochemical and Histopathological Evidence on the Beneficial Effects of Essential Oil of Pistacia atlantica Oleoresin in Acetic Acid-induced Colitis

Pistacia atlantica subsp. kurdica is an endemic plant of Iran which belongs to Anacardiaceae family. This plant has been proposed as an efficacious remedy for gastrointestinal diseases such as inflammatory bowel disease, colitis, and peptic ulcer.

In this study we decided to evaluate the efficacy and pharmacological mechanisms involved in anti-colitis effect of essential oil of Pistacia atlantica in Wistar rats.

Sixty Wistar rats were selected for this study and were categorized to 6 groups. Experimental colitis was induced with 3% acetic acid solution. Animals of treatment groups received different daily doses of the essential oil (25, 50, and 100 mg/Kg, orally) and.Sulphasalazine (as the standard drug), for 7 days. At the end of the study, the rats were sacrificed and the colon was removed and assessed for macroscopic and microscopic changes. Also, in order to identify the mechanisms involved in anti-colitis effect of this natural drug, the level of cyclooxygenase (COX)-2 were evaluated.

The essential oil of Pistacia atlantica gum significantly reduced macroscopic and microscopic scores of colitis compared with control group (P <0.01). The essential oil with the dose of 100 mg/kg showed the highest anti-colitis effect. The oil of P. atlantica remarkably suppressed the level of COX-2 in colon tissue (P <0.05).

This research has proved the protective effect of oral administration of essential oil of P. atlantica gum on ulcerative colitis in rats. This natural drug performs anti-colitis potential through inhibiting the pro-inflammatory cytokines.