Aristolochic acid (AA-I), a naturally occurring nitrophenanthrene carboxylic acid, commonly found in the plant family Aristolochiaceae, that are used in traditional Chinese medicine. Aristolochic acid exhibits nephrotoxic, carcinogenic, and mutagenic activities and can cause aristolochic acid nephropathy, and urothelial malignancies. The FDA has issued a strong warning to consumers to avoid herbs containing the chemical aristolochic acid. The mechanisms underlying AA-I toxicity in the kidneys are poorly understood. However, was found a protein α-actinin-4 that is inhibited by AA-I, resulting in kidney disease.

Tenuazonic acid is one of the major Alternaria mycotoxins commonly found as a natural contaminant in food. Tenuazonic acid contamination has been linked to esophageal cancer in human populations at risk of high exposure. Tenuazonic acid inhibits protein synthesis by suppression at the ribosome. Tenuazonic acid was shown to inhibit 12-O-tetradecanoyl phorbol-13-acetate (TPA) induced ornithine decarboxylase (ODC) activity in a mouse model, and in turn suppressed mouse skin tumor promotion. In addition, this compound has been shown to be a new type of Photosystem II inhibitor.