Tae Jin Shim

Modifying effect of diallyl sulfide on colon carcinogenesis in C57BL/6J-ApcMin/⁺ mice.

Diallyl sulfide (DAS), a flavoring compound derived from garlic, is considered to have cancer chemopreventive potential in experimental animals and humans. This study was designated to examine possible chemopreventive effects of DAS on colon carcinogenesis using genetically engineered transgenic ApcMin/⁺ mice, a well-established animal model for familial adenomatous polyposis (FAP) and sporadic colorectal cancer. Male C57BL/6J-ApcMin/⁺ mice were divided into three groups. Animals of group 1 were placed on the basal diet (AIN-76A) as non-treated controls. Animals of groups 2 and 3 were given DAS- containing diets (in doses of 100 and 300 ppm, respectively). All mice were sacrificed at the end of week 10 of the experiment. Histopathological investigation revealed that the incidence of colonic polyps was decreased dose-dependently by 19% (13/16) in group 2 and by 32% (13/20) in group 3 compared to the 100% incidence (10/10) in group 1. The multiplicity of colonic polyps per mouse was also slightly decreased by DAS treatment (1.88 ± 0.35 in group 2 and 1.63 ± 0.36 in group 3) compared to 2.00 ± 0.39 in group 1. On the other hand, there were no significant differences in the numbers of total polyps per mouse in the small intestine between the groups. Taken together, we suggest that DAS may exert promising inhibitory effects on colon carcinogenesis in the transgenic ApcMin/⁺ mice.

Preventive effect of thiacremonone on the hepatocarcinogenesis initiated by N -nitrosodiethylamine in rats

The present study was carried out to examine the chemopreventive effects of thiacremonone, which is found in heated garlic, on the formation of the preneoplastic foci and glutathione-dependent detoxifying enzyme activities in rat hepatocarcinogenesis. F344 rats were given an intraperitoneal injection of N-nitrosodiethylamine (DEN) at a dose of 200 mg/kg body weight and were then administered a gavage of thiacremonone 2 weeks after initiating the DEN treatment. All animal were subjected to a 2/3 partial hepatectomy at 3 weeks after DEN initiation. The numbers and the placental glutathione S-transferase positive (GSTP+) foci in the thiacremonone-treated groups decreased significantly compared with those in the DEN alone group. Thiobarbituric acid reactive substances content in the thiacremonone treated group (10 mg/kg) decreased significantly compared with that in the DEN alone. These results suggest that thiacremonone may have potential chemopreventive effects on rat hepatocarcinogenesis induced by DEN.