Abstract
BAKGROUND: Ulcerative colitis (UC) is an inflammatory bowel disease that can be treated with many medications but they have various side effects and low cure rate. So, the need for finding novel drugs with better healing characters and less toxicity would be mandatory. Achillea millefolium (A. millefolium, Yarrow) has been traditionally used to treat bleeding, ulcers, wounds, liver, and bile disorders, and recently it has been shown to have anti-ulcer, analgesic, anti-inflammatory, antioxidant, and appetizing effects that make it as a good candidate for UC. METHODS: UC was induced with intra-rectal instillation of acetic acid. A. millefolium hydroalcoholic extract (AMHE, 200, 400, and 600 mg/kg/day) and essential oil (AMEO, 62.5, 125, and 250 μl/kg/day) were given to six groups of male Wistar rats for 5 days. Dexamethasone (1 mg/kg/day, intra-peritoneal) and mesalazine (100 mg/kg/day, orally) were used as reference drugs. Colon tissue specimens were separated for assessing macroscopic, pathologic, and biochemical markers. RESULTS: For AMHE, 77.2 mg/g equivalent to gallic acid was obtained for total phenols. Main assessed markers, including ulcer index, total colitis index, colon weight/length ratio, rats' weight gain, and malondialdehyde levels were significantly improved in AMHE (400 and 600 mg/kg/day) and AMEO (125 and 250 μl/kg/day) groups compared to controls. Myeloperoxidase activity was only attenuated in AMHE groups significantly. CONCLUSIONS: Both AMHE and AMEO were effective in healing experimental colitis. It seems antioxidant, anti-inflammatory, and anti-ulcer activities of Yarrow are responsible for these beneficial effects. Further studies are warranted to elucidate the exact mechanisms involved.