Plant acids found in TCM to get scrutiny

Review sought after study finds risks of cancer, organ damage

The China Food and Drug Administration will conduct risk assessments of drugs that contain potentially dangerous plant acids and may limit or ban their use.

The CFDA made the announcement on Monday following a study published in the journal Science Translational Medicine on Oct 18 that suggested the substances may be linked to liver cancer in Asia.

The report said stronger measures are needed to prevent people from consuming the substances - called aristolochic acids - which are found in many types of plants. The plants have been used in traditional Chinese medicine to treat a variety of symptoms and diseases, such as arthritis and inflammation.

The study stirred widespread concern among members of the public in China, which reports about half the world's new cases of liver cancer every year, according to the World Health Organization.

All pharmaceutical companies that use materials containing aristolochic acids will be required to conduct safety tests; otherwise the CFDA will cancel permits for production of drugs containing the acids and order them to halt production, the statement said. The statement did not give the deadline.

After the CFDA has reviewed the companies' evaluations and their proposed safety measures, the companies will be expected to cease production of drugs containing aristolochic acids when the risks are found to outweigh the benefits, it said.

For products that bring more benefits than risks, on the other hand, the producers should revise and improve specifications for their safe use, it said.

The study said that aristolochic acids have been linked to cancers in the urinary tract and may lead to kidney failure - a finding confirmed by the CFDA, which said kidney damage and possibly even kidney cancer can result from their use.

The study also said the acids may cause liver cancer, but the CFDA said it saw no direct link to liver cancer in China. Surveys show that most liver cancer cases in China are caused by hepatitis B, it said.

The WHO has included aristolochic acids in a list of cancer-causing substances.

TCM drugs containing aristolochic acids have been used in China for more than 1,000 years. Currently 47 oral TCM preparations containing the substance are available in the domestic market, the CFDA said.

Herb products containing the chemicals have not been approved by the United States Food and Drug Administration and are often marketed as dietary supplements or "traditional medicines", according to the National Cancer Institute in the US.

Some other countries, such as Britain and Germany also have rules that limit or ban the use of the acids, the CFDA said.

Since 2003, China has taken a number of steps to control risks associated with aristolochic acids, including forbidding the use of certain herbs that contain high levels.

With those measures in place, the number of cases of kidney damage related to the acids in China decreased greatly, and no report of kidney cancer directly caused by the acids has been reported, the administration said.

Liang Aihua, a TCM researcher at the Chinese Academy of Chinese Medical Sciences, said drugs are poison in proportion to the amount ingested, as well as their time in the body. International standards have been set limiting the use of other potentially poisonous substances to ensure their safety, she said.

Moreover, TCM has stressed processing techniques to reduce drugs' poisonous nature, and many unique methods have been adopted for safety, she added.

"Long-term use of any drug in large doses will likely result in negative reactions or poisonous effects," she said. "Specifications for the use of TCM drugs should be further regulated to provide alerts to users about possible side effects."

wangxiaodong@chinadaily.com.cn