EFFECT OF ALLIXIN, A PHYTOALEXIN PRODUCED BY GARLIC, ON MUTAGENESIS, DNA-BINDING AND METABOLISM OF AFLATOXIN-B1

Allixin, a phytoalexin isolated from garlic, was examined for its effects on aflatoxin B1(AFB1)-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 [H-3]AFB1 to calf thymus DNA and on the formation of metabolites of [H-3]AFB1 were also determined. Allixin showed a dose-related inhibition of Histidine+ revertants induced by AFB1. Allixin at 75-mu-g/ml inhibited [H-3]AFB1 binding to calf thymus DNA and reduced formation of AFB1-DNA adducts. In addition, allixin exhibited a concentration-dependent inhibition of the formation of organosoluble metabolites and the glutathione conjugates of [H-3]AFB1. The data indicate that the effect of allixin on AFB1-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.