Chemopreventive effects of aloe against genotoxicity induced by benzo[a]pyrene.

Chemopreventive effects of aloe against benzo[a]pyrene (BaP) mutagenicity were investigated in the Salmonella typhimurium bacterial mutation assay, the chromosome aberration assay using Chinese hamster ovary (CHO) cells, and the mouse micronuclei test using bone-marrow cells. In the bacterial assay, aloe produced a concentration-dependent decrease in the number of mutant colonies induced by BaP. The chromosome-damaging responses of BaP in CHO cells were abolished by treatment with aloe, approximately to the level seen in control. In the in vivo mouse bone-marrow micronuclei test, pretreatment of aloe 24 h prior to BaP treatment reduced the frequency of micronucleated polychromatic erythrocytes. In the cells of CHO and bone marrow treated with aloe, glutathione (GSH) levels were shown to be higher and extracellular discharge rate increased as incubation time with aloe rose. MDR1 and MRP2 gene were more expressed in Hepa c cells than in NTCC cells, but there was no change in BCRP gene expression. The antimutagenic effects of aloe were statistically significant and concentration dependent. These results demonstrated that aloe might exert chemopreventive effects against BaP-induced mutagenicity.