Milk thistle extract (silibinin) has been found to kill skin cells that have become mutated, via exposure to UVA radiation, and also to protect against UV-induced skin cancer and photo-aging, by two new studies from the University of Colorado Cancer Center.
Milk thistle extract (and silibinin) has long been known for its medicinal and culinary uses. They have very likely been in use for hundreds of thousands of years. Much like the extremely nutritious plant stinging nettles, and the highly medicinal dandelion plant.
“When you have a cell affected by UV radiation, you either want to repair it or kill it so that it cannot go on to cause cancer. We show that silibinin does both,” says Rajesh Agarwal, PhD, co-program leader of Cancer Prevention and Control at the CU Cancer Center and professor at the Skaggs School of Pharmacy and Pharmaceutical Sciences.
One of the studies, just published in the journal Photochemistry and Photobiology, investigated human skin cells that were exposed to UVA radiation. UVA radiation is the main type of radiation that reaches the Earth from the Sun, making up roughly 95% of the total radiation. “The Agarwal Lab treated these UVA-affected cells with silibinin. With silibinin, the rate at which these damaged cells died increased dramatically.”
“When you take human skin cells — keratinocytes — and treat them with silibinin, nothing happens. It’s not toxic. But when you damage these cells with UVA radiation, treatment with silibinin kills the cells,” Agarwal says. This effectively removes the mutated cells that may otherwise lead to some forms of cause skin cancer and also photo-aging.
“Specifically, the study shows that pretreatment with silibinin resulted in higher release of reactive oxygen species (ROS) within the UVA-exposed cells, leading to higher rates of cell death.”
The other study, published in the journal Molecular Carcinogenesis, “shows that instead of beneficially killing cells damaged by UVA radiation, treatment with silibinin protects human skill cells from damage by UVB radiation, which makes up about 5 percent of the sun’s radiation reaching Earth.”
“Again, remember Agarwal’s suggestion that the prevention of UV-induced skin cancer can happen in two ways: by protecting against DNA damage or by killing cells with damaged DNA. With UVA, silibinin kills; with UVB, it protects, in this case by increasing cells’ expression of the protein interleukin-12, which works to quickly repair damaged cells.”
“It has been 20 years of work with this compound, silibinin,” Agarwal says. “We first noticed its effectiveness in treating both skin and solid cancers, and we now have a much more complete picture of the mechanisms that allow this compound to work.”
Agarwal and the other researchers are continuing to explore the effectiveness of silibinin in the prevention and treatment of various forms of cancer. They are currently restricted to “cell lines and mouse models, and are working toward human trials of silibinin-based therapeutics.”
To date, milk thistles have been noted for possessing a wide variety of medicinal uses. Since ancient times, and likely into prehistory, they have been noted for their very beneficial effects on the liver. They are very effective both in treating liver damage, and in preventing it. There is also very good evidence that they can prevent death after the accidental ingestion of certain poisons, such as the death cap mushroom.
Milk thistles also have a long history of use as a food. The whole plant is edible if properly prepared. The roots and greens in particular are noted as being very good, with the greens tasting somewhat like spinach.
Source: University of Colorado Denver