Modifying role of dietary factors on the mutagenicity of aflatoxin B 1: In vitro effect of vitamins

Abstract

19 vitamins including some derivatives have been tested for their ability to suppress mutagenic activity of aflatoxin B 1 (AFB 1) towards Salmonella typhimurium strain TA100 activated with a rat-liver metabolic activation system. Several vitamins have shown an ability to inhibit the mutagenic potency of AFB 1. The values of ID 50, i.e. the dose required to inhibit mutagenic activity by 50% calculated from dose-response curves for each vitamin show retinoids, riboflavin, folic acid, menadione, cyanocobalamin, ascorbic acid and pyridoxine to be significantly antimutagenic. Although inhibition by vitamins is apparent over a range of AFB 1 concentrations, their effect is more pronounced at lower concentrations of AFB 1. When combined data are expressed in terms of specific mutagenicity, riboflavin, retinol and menadione have been found to possess exceptional inhibitory ability in as much as, on a molar basis, only 15–40-fold excess vitamins can inhibit the mutagenic potency of AFB 1 by 50%. Their action is possibly mediated through interaction with microsomal activating enzymes. Previous evidence from this laboratory about their inhibitory action on DNA-adduct formation and metabolic activation together with the present results suggest that certain vitamins notably retinoids and riboflavin may have potential anticarcinogenic activity against AFB 1.