Rajesh Agarwal from Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado in Denver, Colorado and colleagues tested four flavonolignans (silimarin) isolated from a Milk T histle extract and found oral feeding of these compounds effectively inhibited the growth of advanced human prostate cancer xenografts in mice.Angiogenesis plays an important role in prostate cancer growth and metastasis and anything that can inhibit angiogenesis can stop the cancer growth. Angiogenesis is a physiological process that leads to making new blood vessels from pre-existing vessels.
Four compounds from Milk T histle extract tested in the study were silybin A, silybin B, isosilybin A and isosilybin B. For the study, mice with prostate cancer xenografts were fed these flavonolignans in two doses (50 and 100 mg/kg body weight) and the tumor stopped growing after the exposure to these Milk Thistle compounds.
The researchers found these flavonolignans induced many physiological changes in the prostate cancer tumor bearing mice. Among other things, these Milk Thistle compounds were found to inhibit tumor angiogenesis biomarkers CD31 and nestin and signaling molecules that are needed for angiogenesis including VEGF, VEGFR1, VEGFR2, phospho-Akt and HIF-1α.
On the other hand, these compounds did not seem to cause any adverse effect on the vessel count in normal tissue in the liver, lung, and kidney of the tumor bearing mice. The researchers concluded " Overall, these studies elucidated the comparative anti-angiogenic efficacy of pure flavonolignans from Milk T histle and suggest their usefulness in PCA )(prostate cancer) angioprevention." Milk T histle is commonly used as a dietary supplement to treat toxin-induced liver damage, Amanita mushroom poisoning, kidney disease in diabetics, high cholesterol, insulin resistance in people with type 2 diabetes who also have cirrhosis, breast cancer, cervical cancer and prostate cancer, and active hepatitis.
