chapter  6_2
12 Pages

Mycotoxins

WithUeno Yoshio

This chapter discusses the information on the genotoxicity, food contamination, analysis and metabolism of genotoxic my-cotoxins, particularly of AFB1, AFM1, sterigmatocystin (ST), ochratoxin A (OTA), and emodin (EM), and related anthra-quinones. The primary culture/DNA repair test using rat and mouse hepatocytes was applied for the evaluation of the genotoxicity of mycotoxins. The initiator tRNA acceptance assay was also introduced for the screening of carcinogens in 20 mycotoxins. The mycotoxin was first isolated from Aspergillus versicolor, and subsequent survey demonstrated that various fungi belonging to the genera Emericella, Chaetomium, Biopolaris, and Penicillium are ST producers. The genotoxicity of ST is based on the epoxidation of the terminal double bond of the bisfuran ring, followed by a covalent binding to guanine residues of DNA at N-7, in a similar manner to AFB. OTA is nephrotoxic, and several epidemiological surveys revealed the association between OTA level in feeds and porcine nephropathy in several European countries. OTA is biotransformed into several metabolites.