RESUMO
Background: Some Thai vegetables may enhance the activities of some phase II enzymes and decrease activities of phase I enzymes. Thus, they may possess cancer chemo-preventive potentials. Objective: Determine the anti-clastogenic activity of Thai vegetable, Siamese cassia (SC), against an indirectacting clastogens, cyclophosphamide (CYP), and 7, 12-dimethylbenz(a)anthracene (DMBA). Methods: Male mice were fed either with semi-purified diet, containing 2% or 4% of ground lyophilized SC leaves, for two weeks prior to administration of clastogens. The anti-clastogenicity of SC leaves using the in vivo erythrocyte micronucleus assay in mice was performed. Blood samples were collected and counted for reticulocytes with and without a micronucleus using the fluorescent microscope. Results: Feeding SC leaves at 2% or 4% in the diets reduced the number of micronucleated peripheral reticulocytes (MNRETs) induced by both CYP and DMBA. However, the effect was statistically significant only at 4% in CYPinduced mice. Conclusion: Siamese cassia leaves possess anti-clastogenic activity against clastogens in mice, particularly in a high dose.