Effectiveness of mesalamine and propolis in experimental colitis.

This study was conducted to investigate the effects of propolis and mesalamine on experimental colitis in rats. Distal colitis was induced in rats by intracolonic instillation of 2 mL of 4% acetic acid. The animals were randomly assigned to 5 groups: group 1, control, (n=8); group 2, colitis, received no treatment (n=8); group 3, colitis+mesalamine, 2 mL once a day via an enema (n=8); group 4, colitis+propolis, 600 mg/kg once a day via intragastric lavage (n=8); and group 5, colitis+mesalamine+propolis for 1 wk (n=8). Levels of nitric oxide were statistically significantly different in comparisons between groups 1 and 2, groups 2 and 3, and groups 4 and 5. Malondialdehyde levels were significantly different when group 2 was compared with groups 3, 4, and 5. A significant difference was observed when group 3 was compared with group 4 for myeloperoxidase. Most propolis-treated rats had normal histology; mesalamine-treated and propolis+mesalamine-treated rats had inflammatory cell infiltration at rates of 50% and 33%, respectively. The investigators concluded that propolis and mesalamine are efficient independently and in combination, but that their combined effect was not observed to be additive in experimental colitis.