Xi Xin, also known as Asarum or Manchurian Wildginger, is a medicinal herb traditionally used in Traditional Chinese Medicine (TCM). The roots of the plant, which are used for medicinal purposes, are called Xi Xin due to their slender and spicy nature.
However, recent studies published in Science Translational Medicine have revealed potential dangers linked to this herb, particularly its association with certain cancers, including liver cancer.
The concerning compound in Xi Xin is Aristolochic Acid (AA), which is found in many plants of the Aristolochiaceae family, including the Asarum species. Research has indicated that AA can cause specific mutations in DNA, leaving a detectable footprint. Such mutations have been frequently identified in liver cancer patients across Taiwan, China, and South Korea, with prevalence rates reported as high as 78% in Taiwan, 47% in China, and 13% in South Korea. [1] The risks of plants belonging to the Aristolochiaceae family became widely recognized following an incident in Europe during the 1990s, when over a hundred people suffered kidney damage, and the compound was identified as a potent carcinogen.
Xi Xin, inclusive of its roots, also contains Aristolochic Acid (AA). The root of Asarum, known as Asari Radix et Rhizoma or Xi Xin, traditionally used in TCM formulations as an analgesic to alleviate headaches, toothaches, and other inflammatory conditions, contains a low level of aristolochic acid (less than 0.5 ppm). However, the entire Asarum plant exhibits a high concentration of AA (1–150 ppm) and can mistakenly be incorporated into manufacturing processes, resulting in a herbal product with a potentially high level of toxicity.[2] Reports also indicate that Xi Xin has potential nephrotoxicity (toxicity in the kidneys). High doses of Xi Xin can cause numbness in the lips, tongue, and extremities, while long-term, small-dose consumption in animals has led to fatty degeneration of the liver and kidneys.
In TCM, Xi Xin is commonly used, often for treating rhinitis and joint pain, is even administered to children. It is one of main ingredient of popular formulas, like xiao qing long tang and du huo di sheng tang. When using Xi Xin in traditional medicine, only a small amount of the slender root end should be used to ensure safety. The use of Xi Xin in traditional medicine is limited to doses of up to 3 grams. Nevertheless, caution should still be exercised when using this plant, particularly in cases where kidney function may be compromised.
Considering the risks associated with Aristolochic Acid (AA) and products containing AA, such as Xi Xin, the U.S. Food and Drug Administration (FDA) has taken steps to regulate and control their usage. As early as 2001, the FDA issued a public health advisory regarding the safety risks of dietary supplements and other products containing AA. This followed numerous reports of severe kidney damage and urinary tract cancers in individuals who had consumed AA-containing products.
In this advisory, the FDA strongly recommended that dietary supplements and other products containing AA should not be sold in the United States. Manufacturers were encouraged to review their product lines to ensure they did not contain AA. Healthcare professionals were advised against recommending or prescribing AA-containing products due to the serious health risks.
This article emphasizes the importance of rigorous safety evaluations and evidence-based usage of traditional medicinal herbs. Even though these plants have been used for centuries for their therapeutic benefits, modern scientific research has identified significant potential health risks. Therefore, both practitioners and consumers should remain vigilant and informed about the potential hazards related to the consumption of such products.
References
1. Yang JD, Hainaut P, Gores GJ, Amadou A, Plymoth A, Roberts LR. A global view of hepatocellular carcinoma: trends, risk, prevention and management. Nat Rev Gastroenterol Hepatol. 2019 Oct;16(10):589-604. doi: 10.1038/s41575-019-0186-y. Epub 2019 Aug 22. PMID: 31439937; PMCID: PMC6813818.
2.Liu SH, Chuang WC, Lam W, Jiang Z, Cheng YC. Safety surveillance of traditional Chinese medicine: current and future. Drug Saf. 2015 Feb;38(2):117-28. doi: 10.1007/s40264-014-0250-z. PMID: 25647717; PMCID: PMC4348117.