Anti-inflammatory and antioxidant potential of Artemisia dracunculus L. aqueous extract against acetic acid induced ulcerative colitis in male Wistar rats

Abstract

Ulcerative colitis (UC) is one of the two types of inflammatory bowel disease (IBD) which is increasing worldover due to modern life style. Patients with UC are prone to develop colorectal cancer. While the disease severity decides the treatment option, researchers look towards herbal medicines with anti-inflammatory properties for minimal or nil side effects. Artemisia dracunculus L., commonly called Tarragon, is a medicinal herb used in traditional Asian medicine mainly in Iran, India, Pakistan and Azerbaijan due to its special compounds. In this study, we tried to elucidate the effects of aqueous extract of tarragon on acetic acid induced ulcerative colitis (UC) in rats.  Male Wistar rats were grouped into four groups of eight each viz., control; experimental control (UC was induced via luminal instillation of 4% acetic acid); and UC induced + aqueous tarragon extract (100 mg/kg) or prednisolone (2 mg/kg) orally for ten consecutive days. Tissue specimens were collected after the experimental period for evaluation of caspase-3 and cyclooxygenase-2 (COX-2) expression by immunohistochemistry. Real-time PCR was used to monitor the levels of IL-1, IL-6 and TNF-α in colonic homogenates. Moreover, the levels of myeloperoxidase, nitric oxide and total antioxidant capacity were measured in colonic homogenates. The results showed that both treatment regimens could similarly reduce the severity of disease symptoms. Treatment with aqueous extract of tarragon caused a better improvement in the levels of myeloperoxidase enzyme, and total antioxidant capacity of colonic homogenates compared to prednisolone. Nevertheless, the levels of the expression of caspase-3, and COX-2 and TNF-α were reduced in UC rats received prednisolone more than UC rats received aqueous extract of tarragon. The was no statistical difference in the levels of nitric oxide, IL-1 and IL-6 between UC rats received tarragon extract or prednisolone. Overall, these findings suggest that the aqueous extract of tarragon is a promising strategy to control ulcerative colitis. Aqueous extract can also be used as an anti-inflammatory and immune system stimulant in conditions where the immune system is damaged.