Mutagenic effect of aflatoxin G1 in comparison with B1.

Available data indicate structure activity relationships in toxicity and carcinogenecity of aflatoxins in the order of B1 greater than G1 greater than G2 greater than B2. This set of tools is useful for investigations in experimental chemical mutagenesis. The present study is the second in a series concerning the activity of this group of aflatoxins on human chromosomes, using the techniques of Geimsa banding and sister chromatid exchanges. The results showed that aflatoxin G1 is a mutagenic agent to human chromosomes. The distribution of breaks on individual chromosomes according to relative length was nonrandom. Chromosomes 1, 2, 3, 4, and 5, the largest chromosomes, have more breaks, whereas chromosomes 19, 20, 21, and 22, the smallest chromosomes, have less than the expected number of breaks. Comparing these results with that of aflatoxin B1, we found that (1) the mutagenic activity of B1 on human chromosomes is higher than that of G1, and (2) although chromosomes 2, 11, 19, and 20 were the most affected by aflatoxin B1, chromosomes 1, 2, 3, 4, and 5 were the most affected by aflatoxin G1. This result indicates structure activity relationships in mutagenecity that are in agreement with those of the toxicity and carcinogenecity of aflatoxins B1 and G1.