Milk Thistle Seed Flavone Inhibits Lung Cancer Progression in Animal Study.

Silibinin, a flavanone derived from the primary flavonoid found in milk thistle (Silybum marianum), silymarin, curbed the angiogenesis of urethane-induced tumors in mice lungs. The study was conducted at the University of Colorado and published in the June 21 issue of the Journal of the National Cancer Institute (98, 12:846-55, 2006).

Researchers injected two groups of mice with either saline or (cancer-causing) urethane, and then fed them normal diets for two weeks. The mice were then fed diets containing different doses of pure silibinin for 18 or 27 weeks. Their lung tissue was examined to evaluate angiogenesis (the formation of new blood vessels) and for enzymatic markers of inflammation, cell proliferation and apoptosis (programmed cell death).

The urethane-injected mice that received silibinin had significantly reduced lung tumors compared to those that had not received silibinin. The urethane group mice that received 1% silibinin for 18 weeks had 93% fewer large lung tumors than the control mice. Also, lung tumors in mice taking silibinin had 41-74% fewer cells that were positive for cell proliferation markers, proliferating cell nuclear antigen and cyclin D1 (a marker of proliferation and cancer). Tumor micro-vessel density was reduced by 89% in the silibinin mice. Administration of silibinin also seemed to decrease lung tumor expression of vascular endothelial growth factor and two related enzymes that that promote lung tumor angiogenesis and progression.

Researchers concluded that silibinin inhibits lung tumor angiogenesis in an animal model and warrants further investigation as a chemo-preventive agent for suppressing lung cancer progression. However, while the milk thistle seed components silymarin and silibinin have been studied for their efficacy and mechanisms against different cancers for over a decade, researchers noted that their study used pure silibinin and not a milk thistle seed extract such as those available as supplements.

Bio-Design offers both Milk Thistle Liquid Extract and Silymarin (powdered extract) capsules.