Milk Thistle Fruit Extract Botanical Adulterants Prevention Bulletin Published

The ABC-AHP-NCNPR Botanical Adulterants prevention Program has published a new bulletin on the adulteration of milk thistle fruit extracts.¹ Dietary supplements made from the extracts of milk thistle fruit are widely used by consumers for the supportive treatment of the liver such as alcohol- or drug-induced hepatitis and cirrhosis, and treatment of dyspepsia and gallstones. The therapeutic benefits of these extracts result from their silymarin content. Silymarin is a collective term denoting a mixture of chemicals known as flavonolignans. Silymarin content standardization is well defined in official monographs for milk thistle extracts such as those published in European and US pharmacopeias.^2,3

Many peer-reviewed publications have shown that the silymarin content in some commercial dietary supplements is much lower than the amounts claimed on the product labels. In part, such discrepancies can be explained by the use of different analytical methods, i.e., the use of high-performance liquid chromatography with ultraviolet detection (HPLC-UV) rather than spectrophotometric methods (ultraviolet or visible light spectroscopy). However, the available data also point to the market occurrence of fraudulent products in the market wherein the silymarin has been reduced or removed without the knowledge of the buyer.

The new bulletin has been written by Allison McCutcheon, PhD, an expert in herbal medicine research in Vancouver, British Columbia. It summarizes the published data on quality issues with milk thistle extracts, details analytical methods to detect adulteration, and informs on the nomenclature, production, and market importance of milk thistle extracts. Twenty-seven medicinal plant experts from academia, government, contract analytical laboratories, analytical equipment manufacturers, and the botanical dietary supplement industry have provided input on the bulletin during the peer-review process.

References

1. McCutcheon A. Adulteration of milk thistle (Silybum marianum). Botanical Adulterants Prevention Bulletin. Austin, TX: ABC-AHP-NCNPR Botanical Adulterants Prevention Program; 2020:1-12.
2. United States Pharmacopeia. Powdered milk thistle extract. USP 43-NF 38. Rockville, MD: United States Pharmacopeial Convention; 2020.
   
3. Silybi mariani fructus. European Pharmacopoeia (Ph. Eur. 10.0). Strasbourg, France: European Directorate for the Quality of Medicines and Health Care; 2020:1499-1501.