Identification and Mutagenicity of Aflatoxicol M1 Produced by Metabolism of Aflatoxin B1 and Aflatoxicol by Liver Fractions from Rainbow Trout (Salmo Gairdneri)
Food and Chemical Toxicology
β-Naphthoflavone (βNF) fed to rainbow trout (Salmo gairdneri) at 50 or 500 ppm in the diet, modified the in vitro metabolism of aflatoxin B1 (AFB1) by the postmitochondrial fraction (PMF) of the liver. Production of aflatoxicol (AFL) was significantly less in the 500 ppm βNF-fed group (33.9 ng/mg protein) than in the control group (45.7 ng/mg protein), aflatoxin M1 production was dependent on the dose of βNF, being greatest in the 500 ppm βNF-fed group (48.9 ng/mg protein), intermediate in the 50 ppm βNF-fed group (3.7 ng/mg protein), and was not detected in controls. A new trout metabolite, 4-hydroxyaflatoxicol (aflatoxicol M1, AFLM1) was also detected in small amounts from in vitro metabolism by liver PMF from βNF-fed trout. Sufficient quantities of AFLM1 for confirmation of identity by ultraviolet spectra, mass spectra and nuclear magnetic resonance spectra were prepared by biotransformation of AFL using liver microsomes and isolation by HPLC. In a modified Ames mutagen assay with Salmonella typhimurium TA98, ALFM1 was 4.1% as mutagenic as AFB1 in a previous determination. The carcinogenicity of AFLM1 to rainbow trout is expected to be considerably less than that of AFB1.
Loveland, P.M., R.A. Coulombe, L.M. Libbey, N.E. Pawlowski, R.O. Sinnhuber and J.E. Nixon (1983). Identification and mutagenicity of aflatoxicol M1 produced by metabolism of aflatoxin B1 and aflatoxicol by liver fractions from rainbow trout (Salmo gairdneri). Food Chem. Toxicol. 21:557-562.