Kahweol and cafestol: inhibitors of hamster buccal pouch carcinogenesis

Kahweol and cafestol, two compounds extracted from green coffee beans, were tested for cancer chemopreventive activity. For the experiment, 60 hamsters were divided into three equal groups and placed on one of three diets. The animals in Group I received a normal diet, whereas the animals in Groups II and III received the same diet supplemented with a 50:50 mixture of kahweol and cafestol. The content of the kahweol and cafestol mixture in these two diets was 0.2 g/kg of food (Group II) and 2.0 g/kg of food (Group III). After the hamsters adjusted to their respective diets, 16 hamsters from each group were selected. The left buccal pouches of these animals were painted three times weekly with a 0.5% solution of 7,12-dimethylbenz[a]anthracene (DMBA) in mineral oil. The 12 remaining hamsters were used as controls. The left buccal pouches of these animals were painted three times weekly with mineral oil. After 13 weeks (39 applications) the hamsters were killed. Multiple tumors were common in animals treated with DMBA; however, the animals receiving kahweol and cafestol in the diet (2 g/kg of food) exhibited a 35% reduction in tumor burden. Further comparisons between Groups I and III showed that this reduction in tumor burden was due to a decrease in tumor number. The results for Group II were inconclusive. Some reduction in tumor number was found, but this was offset by an increase in the size of the tumors.