Ochratoxin A: Toxicity, oxidative stress and metabolism

Ochratoxin A (OTA) is a widespread mycotoxin commonly found as a corn contaminant. It has been shown to be nephrotoxic, hepatotoxic, teratogenic and immunotoxic to several species of animals and to cause kidney and liver tumors in mice and rats. The focus of this article is primarily intended to summarize the progress in research associated with oxidative stress as a plausible mechanism for OTA-induced toxicity as well as its metabolism. The present review shows that studies have been carried out for decades to elucidate the production of reactive oxygen species (ROS) and oxidative stress as a result of OTA treatment and have correlated them with various types of OTA toxicity, indicating that oxidative stress plays critical roles in the toxicity of OTA. The major metabolic pathways of OTA are hydrolysis and a small percentage of absorbed OTA is hydroxylated. CYP450, carboxypeptidase A, trypsin, α-chymotrypsin and cathepsin have been shown to be able to degrade OTA. Most metabolites of OTA are less toxic than OTA except OP-OTA. Further understanding of the role of oxidative stress in OTA-induced toxicity will throw new light on the use of antioxidants, scavengers of ROS, as well as on the blind spots of the metabolism and metabolic enzymes of OTA. The present review might contribute to reveal the oxidative stress-induced toxicity of OTA and help to protect against its oxidative damage.