Influence of benzoflavone on aflatoxin B1-induced cytotoxicity, mutation, and transformation of C3H/10T1/2 cells.

Aflatoxin B1 (AFLB1), a metabolite of the fungus Aspergillus flavus, is hepatotoxic and hepatocarcinogenic in several animal species and is thought to play an etiological role in human liver cancer. C3H/10T1/2 clone 8 mouse embryo fibroblasts are killed, mutated, and morphologically transformed byAFLB1. 7,8-Benzoflavone, a known inhibitor of aryl hydrocarbon hydroxylase, inhibits this enzymatic activity in C3H/10T1/2 cells. Furthermore, benzoflavone inhibits the binding of AFLB1, to the DNA of C3H/10T1/2 cells. Benzoflavone also inhibits AFLB1-induced cytotoxicity and mutation of C3H/10T1/2 cells, as well as inhibiting the activation of AFLB1 into mutagenic metabolites capable of reverting the Ames Salmonella tester strain TA98. Interestingly, benzoflavone had no effect on the oncogenic transformation of these cells by AFLB1. Therefore, benzoflavone inhibits the DNA binding, cytotoxic, and mutagenic effects of AFLB1 but does not reduce the morphological transformation of C3H/10T1/2 cells by this mycotoxin.