Anti-inflammatory effect of Pistacia atlantica subsp. kurdica volatile oil and gum on acetic acid-induced acute colitis in rat

Background and objectives: Baneh tree or Pistacia atlantica subsp. kurdica is an endemic plant of Iran which belongs to Anacardiaceae family. It has various traditional uses including astringent and anti-diarrheal as well as improving some of the symptoms of gastrointestinal upsets. In this study we decided to investigate the effects of various fractions of baneh gum with different doses in an animal model of ulcerative colitis as one of the important chronic inflammatory bowel diseases of the gastrointestinal tract. Methods: The volatile oil and aqueous baneh gum suspensions were prepared and the constituents of the volatile oil were analyzed by GC/MS. They were used to treat colitis induced by acetic acid 4% in rats. Three doses of gum (100, 200 and 400 mg/kg) were administered both orally (p.o.) and intra-rectally (i.r.) while volatile oil was administered p.o. with doses 100, 200 and 400 µl/kg for four constitutive days. Anti-inflammatory effects of the test compounds were compared with oral prednisolone and hydrocortisone enema. Wet colon weight/ length ratio and tissue damage scores and area as well as indices of colitis and tissue myeloperoxidase activity were evaluated for each specimen. Results: Alpha-pinene was the main constituent of baneh volatile oil (41.23%). We observed therapeutic effects in applied doses of oral gum as well as volatile oil to reduce all indices of colitis and myeloperoxidase activity. Unlike the oral form of gum, its rectal administration was not significantly effective to improve colitis. Conclusion: This research has proved the anti-inflammatory potential of oral gum of Pistacia atlantica subsp. kurdica and its volatile oil in an experimentally induced colitis.