Action of vitamin A on DNA adduct formation by aflatoxin B1 in a microsome catalyzed reaction.

The effect of vitamin A and some derivatives has been studied on the formation of DNA adduct by aflatoxin B1 (AFB1) in an in vitro reaction catalyzed by rat liver microsomes. Retinol, retinal, all trans retinoic acid and two retinyl esters were found to inhibit the adduct formation in a dose-dependent manner. The inhibition by retinol showed that it was prompt and could be reversed by increasing microsome concentration. Retinol also inhibited the formation of AFB1 adduct with microsomal protein. The inhibition of adduct formation with both DNA and protein was still apparent when repurified microsomes were used after pretreatment with retinol. Retinol inhibited adduct formation by virtue of its ability to interact with microsomal enzyme component(s), thereby interfering with the bioactivation of AFB1. The data are suggestive of a potential anticarcinogenic role for vitamin A against AFB1.