[No Title Available]

Abstract

The antimutagenic and anticarcinogenic effects of propolis, a honeybee product, were evaluated in male Wistar rats, using the comet assay and the aberrant crypt foci (ACF) assay. For both tests, animals were treated with the colon carcinogen 1,2 dimethylhydrazine (DMH) for two weeks (two s.c. injections/week) to induce DNA damage and ACF. The animals were divided into groups that received 3 different propolis concentrations (10, 30 and 90 mg/kg b.w., by gavage), either pre-and simultaneously with DMH (ACF and comet assay), or post-DMH treatment (ACF assay). Blood samples were collected from the periorbital vein plexus 4 h after the last DMH treatment for the comet assay. For the ACF assay, the animals were sacrificed two weeks after the last DMH injection. The results showed that propolis had no clear effect on DNA damage induced by DMH in blood cells when evaluated by the comet assay. However, when administered after DMH, propolis caused a significant reduction in the total number of aberrant crypts in the distal colon. These results suggest that propolis does not clearly protect blood cells against DMH genotoxicity, but it has a protective effect on the development of colon carcinogenesis, reducing preneoplastic lesions.