The effect of Hypericum perforatum (St. John's Wort) on experimental colitis in rat.

The aim of the present study was to investigate the effect of Hypericum perforatum (HP) on the inflammatory and immune response of colonic mucosa in rat with induced inflammatory bowel disease and that on various enzyme activities in blood and bowel tissue. Male Wistar albino rats were divided into three main groups: control, third day, and seventh day of colitis. Third-day and seventh-day groups were divided into four subgroups. Colitis was induced in all groups except the control group by 2,4,6-trinitrobenzene sulfonic acid (TNBS). The colitis group received saline; treatment groups received HP extract (50, 150, and 300 mg/kg/day, respectively). Glutathione (GSH), catalase (CAT), and malondialdehyde (MDA) activities in blood were measured. Catalase, myeloperoxidase (MPO), glutathione peroxidase (GSH-Px), glutathione reductase (GR), malondialdehyde, and nitric oxide (NO) activities were measured from tissue samples. Colonic damage was significantly reduced by HP extract. Macroscopic scoring of colonic damage significantly reduced in groups given HP extract compared with in the colitis group (P < 0.001). Blood catalase levels were reduced in the HP (150 mg/kg/day) compared with the colitis group (P < 0.01). Blood GSH levels significantly increased in groups treated with HP compared with control (P < 0.001) on the third and seventh day. Tissue GR levels reduced in the colitis and HP (50 mg/kg/day) groups compared with control (P < 0.05). Tissue MPO activity increased in the colitis and treatment groups compared with control (P < 0.007). GSH-Px levels increased in the colitis group compared with control at day 3 (P = 0.006). HP has a protective effect on TNBS-induced inflammatory bowel disease (IBD), probably due to an anti-inflammatory and antioxidant mechanism.