Aflatoxin

    Aflatoxin B1 (AFB1) is an aflatoxin produced by Aspergillus flavus and A. parasiticus. Aflatoxin B1 is a common contaminant in a variety of foods, including peanuts, cottonseed meal, corn, and other grains; as well as animal feed. It is considered the most toxic aflatoxin and is associated with an increased risk of hepatocellular carcinoma (HCC) – liver cancer.

   AFB1 is metabolized by cytochrome p450 enzymes leading to the formation of the reactive intermediate afb1-8,9-epoxide (AFBO), which can lead to the formation of DNA adducts (a type of DNA lesion) and increase the risk of liver damage, which can lead to cirrhosis and hepatocellular carcinoma. DNA adducts interact with the guanine bases of liver cell DNA and can lead to mutations, including in the TP53 gene, one of our main tumor suppressors, which contributes to HCC.

     The main cytochrome P450 enzyme involved in AFB1 detoxification is CYP1A2. There are genetic risk variants of the CYP1A2 gene, which lead to greater enzyme activity, consequently greater AFBO formation, higher levels of DNA adducts and consequently greater cirrhosis and hepatocellular carcinoma. Smoking is a potent inducer of CYP1A2 along with strenuous exercise, which can further increase AFBO production and the risk of cirrhosis and HCC. Apiaceous vegetables, such as carrots, parsnips, celery and parsley can help inhibit CYP1A2, which can balance CYP1A2 enzyme activity and help reduce the risk of cirrhosis and HCC.

 

Reference:

Hamid AS, Tesfamariam IG, Zhang Y, Zhang ZG. Aflatoxin B1-induced hepatocellular carcinoma in developing countries: Geographical distribution, mechanism of action and prevention. Oncol Lett. 2013 Apr;5(4):1087-1092. doi: 10.3892/ol.2013.1169.