A new, plant-based anti-cancer treatment is showing promising signs in horses with melanoma, German researchers have learned.

Betulinic acid, already used for treating human melanomas, could become an effective and safer alternative for treating equine melanoma compared to traditional chemotherapies, said Reinhard Paschke, PhD, Prof. Dr. habil., of Martin Luther University, in Halle, Germany.

Betulinic acid comes from the bark of white birch and similar trees. It attacks cancer cells by breaking down the membranes of the mitochondria—the cell’s “energy factory.” If a cancer cell’s mitochondria malfunctions, it lacks energy and, therefore, will die.

Paschke said he decided to test betulinic acid on equine melanomas when the owner of a gray horse contacted him after reading his research on melanoma treatment in dogs two years ago.

In their pilot study, he and colleagues tested the effects of betulinic acid, as well as two man-made derivatives, on the cells of two kinds of equine melanoma lines in a laboratory setting. The two derivatives are easier to work with because they dissolve better in water, Paschke said. All three of the products caused both kinds of cancer cells to die, mostly within 24-48 hours of treatment; the most effective treatment was actually one of the derivatives (NVX-207), which caused “high cytotoxicity” (high amount of cell death), he said.

The researchers then moved on to a tolerance study in live animals. The purpose of that experiment was not to test the drug’s efficacy, but to make sure horses can handle the treatment plan safely and without serious side effec