But more than five years ago, researchers at California Pacific Medical Center in San Francisco began focusing their attention on a far tamer compound in the marijuana plant, an ingredient called cannabidiol.
"Cannabidiol is a non-toxic agent from cannabis that is not psychoactive," says Sean McAllister, Ph.D., a lead researcher in the group's recent study.
McAllister and colleague Pierre Desprez, Ph.D., now believe they are ready for human trials, using the compound to treat metastatic cancer. The pair has produced a synthetic version of cannabidiol, also known as CBD, which they say targets a specific gene in the body related to the spread of cancer.
"We found this one compound, CBD, had a specific effect on metastatic cancer cells, very aggressive tumor cells. The bad cancer cells, the ones that spread throughout the body," said Desprez.
In their recently published study the team documented that effect on brain cancer in a large scale animal trial. They say brain scans revealed the disruption of the tumor cells after the cannabidiol was used to switch off a specific gene regulator.
"We find when you treat with CBD, you down regulate the expression of this protein, and that inhibits the disease process," explains McAllister.
Desprez believes the effect may have to do with a natural defense mechanism in the plant, which he says protects it from insects by retarding their development.
"So maybe the plant is making these compounds to combat the development of insects and we can use the compound to target cancer cells that act like embryonic cells," Desperz theorizes.
The team believes the current results, coupled with the non-toxic nature of CBD, is now encouraging enough to warrant human trials, which they hope to secure funding for in the upcoming months. In anticipation, the team has designed two trial models, one for brain cancer and the other for breast cancer.