Hamsters: 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). 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.

To evaluate the potential cell morphological changes as a result of treatment with cafestol and kahweol in malignant mesothelioma cells, MSTO-211H cells were treated with cafestol (0–90 uM) or kahweol (0–60 uM) of various concentrations and monitored for 48 hrs. The MSTO-211H cells was changed to round cell shape, cell shrinkage was observed, and cell volume was decreased in those treated with cafestol (60 and 90 uM) and kahweol (40 and 60 uM). The IC50 value of the cafestol and kahweol after 48 hrs of incubation was estimated as 82.07 uM and 56.00 uM in MSTO-211H cells and H28 cells, respectively. Cell viabilities were calculated as 99.3 ± 1.8%, 75.1 ± 2.6%, and 42.1 ± 2.2% of the control at 30, 60, and 90 uM cafestol in MSTO-211H cells and H28 cells, respectively.