Aristolochic Acids (AA) is a natural compound found in Aristolochia and Asarum plants. These plants are commonly used in traditional herbal remedies for many purposes including weight loss and slimming. AA has been officially banned in Europe since 2001 and in Singapore since 2004. Some herbs that contain AA have been banned in Taiwan since 2003, and in China, the use of some, but not all, AA-containing herbs in traditional medicine is restricted. While the United States Food and Drug Administration has issued warnings about herbs containing AA, their sale is unrestricted as long as they are labelled correctly and no health claims are made.
However, the effects of such bans may take years to materialise; so it could be years before rates of AA-associated cancers fall. In addition, herbs containing AA are easily available online. To complicate matters, herbs are often bundled and sold as formulations rather than individually, and some formulations might use herbs containing AA. Furthermore, herbs containing AA are sometimes improperly labelled, making it difficult for suppliers and consumers to be certain of the constituents of multi-herb formulations.
Scientists have revealed a decisive link between AA used in herbal remedies, and liver cancers. Using mutational signature analysis, the researchers found that liver tumors had been exposed to AA, which had mutated many genes that cause cancer.
The team first sequenced the DNA of 98 liver cancers from Taiwan. Using mutational signature analysis, they found high numbers of AA-related mutations in over three-quarters of these cancers. Mutational signatures are patterns of changes in the DNA caused by mutagens, compounds that cause cancer.
"Although we knew that there was exposure to AA in Taiwan, we were very surprised to find such a high proportion of liver cancer sufferers had exposure to AA," said the author.
The team then looked at publicly available data on mutations from 1,400 liver cancers from around the world. While AA is found in plants used in traditional medicine worldwide, the team found high prevalence of exposure in other parts of East and Southeast Asia.
AA, a known mutagen, was previously implicated in kidney and urinary tract cancers in Taiwan. In this new study, the researchers confirm that AA mutations are involved in causing liver cancer as well. "This was also another surprising finding of this study," added another author.
Herbal remedies containing aristolochic acid may cause liver cancer
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