Thymol has beneficial effects on the experimental model of ulcerative colitis

Thymol, a natural aromatic monoterpene phenol derived from thymus, possesses anti-inflammatory benefits. Here, we evaluated the potential of thymol therapy in improving an animal model of ulcerative colitis.

Luminal instillation of acetic acid was used to induce colitis in male Wistar rats. Treatment groups daily received prednisolone (2 mg/kg, orally) or thymol (100 mg/kg, orally) for 10 consecutive days. Then, the rats were euthanized and tissue specimens were collected for evaluation of cyclooxygenase-2 (COX-2) expression by immunohistochemistry. Furthermore, the levels of total protein, nitric oxide, myeloperoxidase, malondialdehyde, IL-1, IL-6, and TNF-α were monitored in colonic homogenates. Eventually, the relative mRNA expression of IκBα and NF-κBp65 was investigated using reverse-transcriptase PCR (RT-PCR) in colonic homogenates.

Both medications could reduce the mortality rate and the clinical scores of ulcerative colitis. The COX-2 expression was significantly reduced in the colons of thymol-treated animals compared to the prednisolone group. Also, the myeloperoxidase activity, nitric oxide level and malondialdehyde intensity were decreased in the colons of thymol-treated animals to a greater extent compared to the prednisolone group. Moreover, the total protein content of guts showed significant increases in the guts of thymol-treated animals in comparison to the prednisolone group. Nonetheless, thymol significantly reduced the levels of IL-6, and IL-1 compared to prednisolone. Both medications caused a significant decrease in the mRNA level of NF-κBp65, though the mRNA level of IκBα did not show significant changes between the groups.

Thymol may be a promising agent to ameliorate ulcerative colitis.