High Performance Liquid Chromatography of Flavonolignans in Commercial Milk Thistle Supplements

Abstract

The fruit from milk thistle (Silybum marianum) contains flavonolignans that posses therapeutic properties. Milk thistle extract is sold and taken as an herbal supplement. However, it is not regulated by the Food and Drug Administration. The amount of flavonolignans in the commercial products is unknown. High-performance liquid chromatography (HPLC) was used to analyze the flavonolignans from six different commercial milk thistle products. The six commercial supplements consistently show lower amounts of total flavonolignans compared to the amount of milk thistle extract stated on the bottle. A consumer would receive the highest amount of total flavonolignans in a capsule by taking the Vitamin Shoppe product. On a cost basis, Origin provides the highest amount of total flavonolignans per capsule at the lowest price.