milk thistle

A substance derived from any of several Old World coarse prickly-leaved shrubs and subshrubs including the plant Silybum marianum. Milk thistle’s active chemical component is silymarin, which is a combination of flavonoids such as silibinin, dehydrosilibinin, silychristin and silydianin. These compounds are antioxidants and may alter the membrane structure of the liver cell, thereby blocking the absorption of toxins; they may also stimulate the production of new liver cells. In addition, milk thistle may increase cellular adenosine triphosphate (ATP) levels, exhibiting dose-dependent cardiac myocyte cytoprotection against doxorubicin. The silibinin component of milk thistle has been shown to inhibit growth factor receptor-mediated mitogenic and cell survival signaling, thereby inhibiting tumor growth. (NCI04)