A new study by researchers from the University of Notre Dame raises important questions about the safety of herbal dietary supplements.p. The supplements, also known as phytopharmacuticals, are medicinal plant preparations that historically have proven effective in treating diseases. These herbal medicines include substances such as St. John’s Wort, Cayenne, goldenseal root and Echinacea.
There is growing demand for herbal supplements in industrialized nations due to mistrust of prescription pharmaceuticals and the consumer perception that “natural” means safe. The World Health Organization estimates that 65 percent to 80 percent of the world’s population meets its primary health care needs through plant-based medicines.
This increased demand has resulted in indiscriminate harvesting of wild species of plant material. The Notre Dame team theorized that commercial preparations of medicinal products from the roots of wild harvested medicinal plants may be subjected to pollution contamination, including heavy metals and organic contaminants, and might pose a serious health risk.
The Notre Dame team used the University’s Inductively Couple Plasma-Mass Spectometry (ICP-MS) facility and Gas Chromatography-Mass Spectometry (GC-MS) to analyze the metal and organic composition of dietary supplements. The analyzed supplements were found to contain one or more heavy metals in surprisingly high abundances. The analysis also showed that two organic compounds, n-hexadecanoic acid and octadecanoic acid, were tentatively identified in the herbal medicines with relatively high concentrations. The two compounds are skin, eye and respiratory irritants.
The researchers suggest that further research is required to identify possible pesticides in herbal medicines. They also note that plant-based medicines are not regulated by governments and that legislative reforms and new technologies are needed to ensure the safety of consumers and the effectiveness of the supplements.
The Notre Dame team included Jinesh C. Jain, manager of the ICP-MS; Clive R. Neal, associate professor of civil engineering and geological sciences; Jeffery W. Talley, assistant professor of civil engineering and geological sciences; Xiangru Zhang, a graduate student; and Matt Padberg, an undergraduate student. Jain received a Plaque of Honor for the study at the International Symposium for Recent Advances in Pharmacology, held Jan. 7-8 in New Delhi, India.
Jain and Praveen K. Saxena, a professor of plant biology at the University of Guelph in Ontario, Canada, are collaborating to develop new technologies to provide toxin-free, consistent and standardized medicinal plant materials.