Plant Extract Fights Brain Tumor

Plant Extract Fights Brain Tumor
Treatment with silibinin, a constituent of milk thistle seeds,
alleviated symptoms of Cushing Disease in cell cultures, animal
models and human tumor tissue. In future, patients might not
have to undergo brain surgery anymore. (Credit: Curtis Clark)
Silibinin has an outstanding safety profile in humans and is currently used for the treatment of liver disease and poisoning. Now scientists have discovered that silibinin can be applied to treat Cushing Disease, a rare hormone condition caused by a tumor in the pituitary gland in the brain. The researchers have filed a patent and now plan clinical trials using silibinin as a non-invasive treatment strategy. Thus, in future, patients might not have to undergo brain surgery anymore. The research was published in the journal Nature Medicine.

Cushing Disease, not to be confused with Cushing’s Syndrome, is caused by a tumor in the pituitary gland in the brain. The tumor secrets increased amounts of the stress hormone adrenocorticotropin (ACTH) followed by cortisol release from the adrenal glands leading to rapid weight gain, elevated blood pressure and muscular weakness. Patients are prone to osteoporosis, infections and may show cognitive dysfunction or even depression. In 80 to 85 % of the patients the tumor can be removed by uncomfortable brain surgery. For inoperable cases, there is currently only one targeted therapy approved which unfortunately causes intense side effects such as hyperglycemia in more than 20 % of the patients.

Scientists now discovered in cell cultures, animal models and human tumor tissue that a harmless plant extract can be applied to treat Cushing Disease. Silibinin is the major active constituent of milk thistle seeds. It has an outstanding safety profile in humans and is already used for the treatment of liver disease and poisoning. After silibinin treatment, tumor cells resumed normal ACTH production, tumor growth slowed down and symptoms of Cushing Disease disappeared in mice.

In 2013, the scientists filed a patent on a broad family of chemical and natural compounds, including silibinin, to treat pituitary tumors. Compared to humans, of which only 5.5 in 100,000 people worldwide develop Cushing Disease, this condition is very common in several pets. For example, 4 % of dogs and even 7 % of horses suffer from Cushing Disease. Thus, the researchers now plan to test special formulations with a very pure substance and slow release of the active component silibinin in clinical trials.
 
Based on material originally posted by Max-Planck-Gesellschaft.