Decrease of gastrointestinal mucosal damage by salicyluric acid compared with salicylic acid in rabbits.

The gastrointestinal mucosal damage following the oral administration of salicylic acid or salicyluric acid was examined in rabbits using a scanning electron microscope. Six and 24 h after treatment with salicylic acid, morphological changes of gastric mucosa were recognized. In rabbits treated with salicyluric acid, however, severe damage in the gastric mucosa was not found after 24 h compared with the treatment with salicylic acid. Following the treatment with salicylic acid, some mucosal damage in the duodenum, jejunum and ileum was observed after 24 h. The surface character of the duodenal, jejunal, ileal, caecal and colonic mucosa were almost identical compared with the control following the treatment with salicyluric acid. It was reported that salicyluric acid is metabolized to salicylic acid by the intestinal microorganisms. From these results, it was suggested that prodrugs utilizing the metabolism of salicyluric acid to salicylic acid by intestinal microorganisms may be useful in reducing gastrointestinal mucosal damage.