Effect of allixin, a phytoalexin produced by garlic, on mutagenesis, DNA-binding and metabolism of aflatoxin B 1

Abstract

Allixin, a phytoalexin isolated from garlic, was examined for its effects on aflatoxin B 1(AFB 1)-induced mutagenesis using Salmonella typhimurium TA100 as the bacterial tester strain and rat liver S9 fraction as the metabolic activation system. The effects of allixin on the binding of [ 3H]AFB 1 to calf thymus DNA and on the formation of metabolites of [ 3H]AFB 1 were also determined. Allixin showed a dose-related inhibition of Histidine + revertants induced by AFB 1. Allixin at 75 μg/ml inhibited [ 3H]AFB 1 binding to calf thymus DNA and reduced formation of AFB 1-DNA adducts. In addition, allixin exhibited a concentration-dependent inhibition of the formation of organosoluble metabolites and the glutathione conjugates of [ 3H]AFB 1. The data indicate that the effect of allixin on AFB 1-induced mutagenesis and binding of metabolites to DNA may be mediated through an inhibition of microsomal P-450 enzymes. Allixin may thus be useful in the chemoprevention of cancer.