Aristolochic acid (AA), a carcinogenic compound found in Aristolochia plants has been confirmed to contribute to the high rates of upper urinary tract urothelial carcinoma (UUC) in Taiwan.
Taiwan has the highest incidence of UUC in the world and at least one-third of its population has consumed herbal products that contain AA. Aristolochic acid is a carcinogen and is nephrotoxic (toxic to kidneys). After it’s ingested and activated, AA forms an adduct (a bond) with our DNA, called an AL-DNA adduct. These adducts are biomarkers (biological markers and evidence of disease), cause cancers and indicate if a person has ingested AA. They also mutate a tumor suppressor gene called TP53. Researchers from the National Taiwan University Hospital and Dr. Grollman from Stony Brook University in Stony Brook, NY examined the DNA of 151 UUC patients in Taiwan and these were compared with 25 patients with renal cell carcinoma (RCC) who were the control group. They discovered that 60 % of patients with UUC and 84 % of patients with TP53 mutations had AL-DNA adducts in their kidney tissue. This provides clear proof of exposure to AA, and that it’s a significant cause of UUC in Taiwan. The study’s results were published in the Proceedings of the National Academy of Sciences.
In a recent study published in Kidney International, AA was also shown to be responsible for Endemic (Balkan) nephropathy, a disease associate with UUC, and localized in Balkan farms. People there had consumed flour products contaminated with Aristolochia.
Traditional Chinese Medicine (TCM) herbal products are not always labelled properly, so some might contain Aristolochia. Damage caused by AA is persistent, and thus those who have consumed Aristolochia products in Taiwan, China, Asia or elsewhere are at an increased risk of developing UUC.
Consumers need to be very careful when using TCM herbal products, because of improper labelling, the possible toxic effects of the plants, and contamination of products with dangerous plants, a fact highlighted recently in the journal PLoS Genetics.